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Solution and crystalline state photochemistry of 2,3-diacyl-substituted benzobarrelenes Yap, Melvin Peng-Kwun 1992

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SOLUTION AND C R Y S T A L L I N E STATE PHOTOCHEMISTRY OF 2,3-DIACYL-SUBSTITUTED  BENZOBARRELENES  by M e l v i n Peng-Kwun Y a p B.Sc,  University of British  A T H E S I S SUBMITTED  C o l u m b i a , C a n a d a , 1986  I N P A R T I A L F U L F I L L M E N T OF  THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF  PHILOSOPHY in  THE FACULTY OF GRADUATE STUDIES (DEPARTMENT  We a c c e p t t h i s to  OF  CHEMISTRY)  t h e s i s as  the required  standard  THE U N I V E R S I T Y OF B R I T I S H April  conforming  COLUMBIA  1992  © M e l v i n Peng-Kwun Y a p , 1992  In  presenting this  degree at the  thesis  in  University of  partial  fulfilment  of  or  by  his  or  her  representatives.  It  is  granted  Department of  O^BMlSlil'^f  The University of British Columbia Vancouver, Canada  DE-6 (2/88)  an advanced  Library shall make  by the  understood  publication of this thesis for financial gain shall not be permission.  for  it  agree that permission for extensive  of this thesis for scholarly purposes may be  department  requirements  British Columbia, I agree that the  freely available for reference and study. I further copying  the  that  head of copying  my or  allowed without my written  ABSTRACT  A and  series  of  2,3-diacyl-substituted  t h e i r photochemistry investigated  solution  m e d i a . The  differences  b e n z o b a r r e l e n e s was  in  the  crystalline  state  i n p h o t o r e a c t i v i t y and p r o d u c t  b e t w e e n t h e s e compounds i n t h e two p h a s e s w e r e d e t e r m i n e d , reactivity  correlations  were  synthesized  e s t a b l i s h e d based  in  selectivity  and  on X - r a y  and  structure-  crystallographic  data. The  photochemistry of  benzocyclooctatetraene and  is  benzosemibullvalenes  Regioisomeric  symmetrically  are  products  use  of  and  the  singlet  excited  triplet  derived  state  excited  from  the  state.  different  pathways taken. photoisomerizations  2a,6c-disubstituted.  of  excited  a  number  of  thereby  state  enabling  through  unusual  was  Photochemical also conducted  shown  investigation in  the  direct  of the a c y l substrate  polymer  controlled  benzobarrelenes  to  The  to  play  of  the  matrix  presence  be  media  groups to  irradiation. in  r e g i o s e l e c t i v i t i e s between the  determined  e f f e c t s were  is  effects.  the 2 a , 5 c - d i s u b s t i t u t e d p r o d u c t s .  interactions  Selectivity  a b e n z o y l s u b s t i t u e n t a s one  crossing,  strikingly  electronic  multiplicity-dependent;  the  of  are  several unsymmetrical benzoyl/ester  and  is  through  triplet-state  p r e d o m i n a n t l y by e l e c t r o n i c  gave  series  d i s u b s t i t u t e d b e n z o b a r r e l e n e s g a v e two b e n z o s e m i b u l l v a l e n e s -  1,2-disubstituted  triplet  formed  rearrangement  S o l u t i o n phase,  intersystem  title  benzosemibullvalenes  "di-TT-me thane"  The  the  the a  of  major  much  benzoyl/methyl to  show  achieve  the  Photolyses  the  solid  of  state  1,2-disubstituted specific  factor  less  enhances  lattice  responsible;  significant ester  variation  role.  system in  was  product  selectivity. Ammonium  and  were p h o t o l y z e d i n  metal  ionsalts  solution  product  selectivities  specific  lattice  and  were  of benzobarrelene-2,3-dicarboxylic acid the  recorded  interaction effects  crystalline to further  prompted  the  design  and  triplet  t h e dominance o f  effects.  rearrangement synthesis  their  support  over e l e c t r o n i c  D i s c o v e r y o f a r a r e "tri-TT-methane" barrelenes  phase;  in  some  of dimethyl  dibenzo-  1,4-dihydro-  1,4,5,8-tetramethyl-1,4-ethenonaphthalene-2,3-dicarboxylate. successfully and  solid  underwent  states.  intramolecular stabilizing Many [1,3]  The  steric  tri-TT-methane  the novel  selectivity  effects  rather  rearrangement was  than  This i n both  rationalized on  the  i n  solution terms  of  basis of electronic  effects. benzosemibullvalene  shifts  from  a  photoproducts  secondary  rearrangements  lead to regioisomeric  many  i n  exist  benzosemibullvalenes  unusual require  photolysis;  found  carbonyl  bond c l e a v e d i n o r d e r f o r t h e [1,3] s h i f t  to  undergo  coincidentally,  benzosemibullvalenes.  photostationary a  were  states.  substituent  It  As was  a  these result,  found  adjacent  r e a c t i o n to take p l a c e .  to  that the  TABLE OF  CONTENTS  T I T L E PAGE  i  ABSTRACT  i  i  TABLE OF CONTENTS  i v  L I S T OF FIGURES  v i  ACKNOWLEDGEMENT  x l i i  DEDICATION  x i v  INTRODUCTION I. II. III. IV. V. VI. VII. VIII.  1  History The E x c i t e d  2 State  3  The D i - T T - M e t h a n e R e a r r a n g e m e n t The T o p o c h e m i c a l Solid  State  8  Principle  17  Reactivity  Photochemical Photochemistry  19  [1,3] S i g m a t r o p i c S h i f t s  27  of Benzobarrelenes  32  Object o f Research  38  RESULTS AND D I S C U S S I O N  44  PART I .  Preparation  of Starting Materials  PART I I .  Characterization Photoproducts  of Disubstituted  PART I I I . P h o t o c h e m i s t r y o f S y m m e t r i c a l l y Benzobarrelenes  45 Benzosemibullvalene 57  Disubstituted  A. P h o t o c h e m i s t r y o f D i m e t h y l 1,4-Dihydro-1,4-ethenonaphthalene-2 , 3-dicarboxylate (29)  73  73  B. P h o t o c h e m i s t r y o f 1,4-Dihydro-1,4-ethenonaphthalene2 , 3 - d i c a r b o x y l i c A c i d (40) 82  C. P h o t o c h e m i s t r y o f 1,4-Dihydro-1,4-ethenonaphthalene2 , 3 - d i c a r b o x y i c Anhydride (41) 94  PART I V .  D. P h o t o c h e m i s t r y o f 2 , 3 - D i b e n z o y l - 1 , 4 - d i h y d r o - 1 , 4 ethenonaphthalene (42)  102  Photochemistry of Unsymmetrically Benzobarrelenes  109  Disubstituted  A. P h o t o c h e m i s t r y o f M e t h y l 2 - B e n z o y l - l , 4 - d i h y d r o - l , 4 e t h e n o n a p h t h a l e n e - 3 - c a r b o x y l a t e (43) 109 B. P h o t o c h e m i s t r y o f E t h y l 2-Benzoyl-1,4-dihydro-1,4ethenonaphthalene-3-carboxylate (44) 129 C. P h o t o c h e m i s t r y o f I s o p r o p y l 2 - B e n z o y l - l , 4 - d i h y d r o l , 4-ethenonaphthalene- 3-carboxylate (45) PART V.  Photochemistry  PART V I .  Photochemistry o f Dimethyl 1,4,5,8-Tetramethyl-1,4dihydro-1,4-ethenonapthalene-2,3-dicarboxylate (47).  PART V I I . P h o t o c h e m i c a l  of Benzobarrlene  [1,3] S h i f t s  Salts  (48-54)  i n Benzosemibullvalenes..  EXPERIMENTAL  II.  171  Synthesis of Starting Materials  179  Photochemistry  205  of Substrates Disubstitued  E-G. P h o t o c h e m i s t r y o f U n s y m m e t r i c a l l y Benzobarrelenes H.  I.  REFERENCES  157  175  A-D. P h o t o c h e m i s t r y o f S j m i m e t r i c a l l y Benzobarrelenes  III.  147  172  General Procedures I.  135  205 Disubstituted  1,4-Dihyro-l,4-ethenonaphthalene-2,3-dicarboxylate Salts  222  245  Dimethyl 1,4,5,8-Tetramethyl-1,4-dihydro-1,4-ethenon a p h t h a l e n e -2,3- d i c a r b o x y l a t e 246  Quantum Y i e l d  Studies  252  255  L I S T OF  FIGURES  INTRODUCTION Figure  0.01  Energy Diagram f o r S e l e c t e d T r a n s i t i o n s  4  Figure  0.02  Energy Diagram f o r General Photophysical Processes  5  Figure  Figure  0.03  0.04  Molecular  l-Benzoyl-4-(a-naphthyl)-bicyclo[2.2.2]o c t a n e (3) and a R i g i d B e n z o p h e n o n e - N a p h t h a l e n e D o n o r - A c c e p t o r System (4) Di-7r-Methane Mechanism R e p r e s e n t e d 1,4-Pentadiene  in  (6)  9  Figure  0.05  Examples o f A c y c l i c  Figure  0.06  Examples o f C y c l i c  Figure  0.07  Examples o f I n i t i a l Bond F o r m a t i o n i n the Di-w-Methane Rearrangement  Figure  0.08  Examples o f S e c o n d a r y Bond C l e a v a g e S e l e c t i v i t y i n the Di-7r-Methane Rearrangement  Figure  0.09  Photochemistry S o l u t i o n and  Figure  Di-ir-Methane  Systems  Di-7r-Methane Systems  18 Cavity  F i g u r e 0.11  Example o f a U n i m o l i c u l a r S o l i d Reaction  State  Figure  Photodimerization p e n t a n o n e (17)  Figure  Figure  Figure  0.13  0.14  0.15  20  22  Benzylidenecyclo23  Enantioselective Transformation of b a r r e l e n e D i i s o p r o p y l E s t e r (18) L a t t i c e Environment of D i i s o p r o p y l E s t e r 18  Dibenzo24  Dibenzobarrelene 26  Symmetry D i a g r a m s D e s c r i b i n g t h e Theory of O r b i t a l  16  in  States  Cohen's Concept o f the R e a c t i o n  of  11  14  of Trans Cinnamic A c i d Crystalline  10  Selectivity  0.10  0.12  7  Overlap  for  Woodward-Hoffmann  [1,3]  Shifts  28  Figure  0.16  Photochemical  [1,3]  Shifts  29  Figure  0.17  Photochemical  [1,3]  Shifts  30  Figure  0.18  Some B e n z o s e m i b u l l v a l e n e s [1,3] S i g m a t r o p i c S h i f t  Studied  for  the 31  Figure  0.19  Figure  0.20  Figure  Figure  Figure  Figure  0.21  0.22  0.23  0.24  Feasible I n i t i a l Bondiing S i t e s i n the Photochemistry of Dibenzobarrelenes  32  P o s s i b l e pathways i n the P h o t o c h e m i s t r y o f 2 , 3 - D i s u b s t i t u t e d Monobenzobarrelenes  34  Phototransformations o f the U n s u b s t i t u t e d Benzobarrelene  35  L i s t o f Some S u b s t i t u t e d Previously Studied  36  Benzobarrelenes  Photochemistry of l-Cyano-2,3-benzobicyclo[4.2.0]octa-2,4,7-triene  38  Symmetrical D i s u b s t i t u t e d Benzobarrelenes Studied  39  Figure  0.25  Unsymmetrical  Figure  0.26  Salts of Benzobarrelene D i c a r b o x y l i c A c i d  41  Figure  0.27  Bridgehead Methylated Barrelene Dimethyl Esters  42  PART I . Figure  Figure  Figure  Figure  Figure  Figure  Benzobarrelenes  Studied  40  PREPARATION OF STARTING MATERIALS  1.01  1.02  1.03  1.04  1.05  1.06  S y n t h e s i s o f B e n z o b a r r e l e n e D i e s t e r 29 f r o m a Diels-Alder Reaction  45  D e r i v a t i o n of Benzobarrelene E s t e r 29  46  Dimethyl  NMR S p e c t r a o f B e n z o b a r r e l e n e 29 a n d D e u t e r a t e d B e n z o b a r r e l e n e 29-D  Partially 48  Preparation of 2,3-Dibenzoyl-l,4-dihydro1,4-ethenonaphthalene (42)  49  Spectra o f Symmetrical Benzobarrelenes a n d 41  51  40  a) P r e p a r a t i o n o f B e n z o y l E s t e r s 4 3 , 4 4 , a n d 4 5 . b) M o n o d e u t e r a t e d B e n z o y l M e t h y l E s t e r  Figure  1.07  NMR  S p e c t r a o f B e n z o y l E s t e r s 43 a n d 45  Figure  1.08  Synthesis of Tetramethyl D i m e t h y l E s t e r 47  (43-D)  53 54  Benzobarrelene 56  PART I I .  CHARACTERIZATION OF DISUBSTITUTED BENZOSEMIBULLVALENE PHOTOPRODUCTS  F i g u r e 2.01  a) S t r u c t u r e o f P e n t a l e n e . b) S t r u c t u r e o f B e n z o s e m i b u l l v a l e n e o r 2a,2b,6b,6cTetrahydrobenzo[a]cyclopropa[cd]pentalene  58  NMR S p e c t r a o f 2 a , 6 c - D i s u b s t i t u t e d B e n z o s e m i b u l l v a l e n e s 29a and 40a  59  NMR S p e c t r a l E x p a n s i o n s o f 2 a , 6 c - D i s u b s t i t u t e d B e n z o s e m i b u l l v a l e n e s 29a and 40a  60  NMR S p e c t r a l E x p a n s i o n s o f 1 , 6 c - D i s u b s t i t u t e d B e n z o s e m i b u l l v a l e n e s 29b a n d 4 3 c  62  NMR S p e c t r a l E x p a n s i o n s o f 1 , 2 - D i s u b s t i t u t e d B e n z o s e m i b u l l v a l e n e s 40b a n d a M i x t u r e o f 4 3 d a n d 4 3 e . . .  64  F i g u r e 2.06  Methyl  65  F i g u r e 2.07  Complexation of 1,2-Disubstituted Benzosemibullvalenes to Eu(hfc)3  66  P l o t s o f Change i n C h e m i c a l S h i f t ( A u ) A g a i n s t t h e M o l e % o f E u ( h f c ) 3 A d d e d f o r Compounds 43d a n d 43e  67  NMR S p e c t r u m a n d E x p a n s i o n o f M e t h y l 6 c B e n z o y l - 2a,2b - d i h y d r o b e n z o [ a ] c y c l o p r o p a [ c d ] pentalene-6b-carboxylate (43f)  69  F i g u r e 2.10  X-ray  70  F i g u r e 2.11  a ) NMR S p e c t r a l E x p a n s i o n o f M e t h y l 6 c - B e n z o y l 2a,6b-dihydrobenzo[a]cyclopropa[cd]pentalene2b-carboxylate (43g). b ) D e c o u p l i n g a t 4.52 ppm  F i g u r e 2.02  F i g u r e 2.03  F i g u r e 2.04  F i g u r e 2.05  F i g u r e 2.08  F i g u r e 2.09  PART I I I  Cis-2-butene-3-carboxylate  3.02  (65)...  C r y s t a l S t r u c t u r e o f Compound 4 3 f  PHOTOCHEMISTRY OF SYMMETRICALLY DISUBSTITUTED  F i g u r e 3.01  Figure  2-Benzoyl  P h o t o c h e m i s t r y o f Compound 29 b y G r o v e n s t e i n e t a l . i n 1969  71  BENZOBARRELENES  Reported 73  M e c h a n i s t i c Study f o r B e n z o c y c l o o c t a t e t r a e n e 29c F o r m a t i o n , P e r f o r m e d b y B e n d e r a n d B r o o k s i n 1975  74  F i g u r e 3.03  Complete P h o t o c h e m i s t r y  76  Figure  Mechanism o f B e n z o s e m i b u l l v a l e n e 29b F o r m a t i o n  3.04  o f Benzobarrelene  29  29a and 77  Flgure  Figure  Figure  Figure  Figure  Figure  Figure  Figure  3.05  3.06  3.07  3.08  3.09  3.10  3.11  3.12  Mechanism o f B e n z o s e m i b u l l v a l e n e 29e F o r m a t i o n from B e n z o c y c l o o c t a t e t r a e n e 29c  79  NMR S p e c t r u m o f Compound 2 9 c R e a c t i o n M i x t u r e Showing S i g n a l s o f Cyclobutene 29d  80  Photoproducts from 1,4-Dihydro-1,4-ethenonaphthalene-2, 3 - d i c a r b o x y l i c A c i d (40)  82  P r o t o n NMR s p e c t r a o f a ) 4 1 d i n DMSO-dg. b ) 41d-D i n DMSO-dg  85  Mechanisms o f B e n z o s e m i b u l l v a l e n e s 40a and 40b F o r m a t i o n  86  a ) R e a c t i o n M i x t u r e P r o t o n NMR S p e c t r a o f B e n z o p h e n o n e S e n s i t i z a t i o n o f 40-D b ) T a b l e o f B o n d " a " a n d "b" L e n g t h s f r o m X-ray A n a l y s i s  88 90  a) S o l i d S t a t e I n f r a r e d S p e c t r u m o f D i a c i d 40. b) S i m p l e R e p r e s e n t a t i o n o f t h e R e a c t i o n C a v i t y o f D i a c i d 40 S h o w i n g t h e H y d r o g e n B o n d A n c h o r s Hydrogen Bonding  E f f e c t s on t h e P h o t o c h e m i s t r y  o f 66  93  Figure  3.13  Photochemistry of Benzobarrelene Anhydride  Figure  3.14  NMR S p e c t r u m o f A n h y d r i d e from D i r e c t P h o t o l y s i s  Figure  Figure  3.15  3.16  92  41  95  41 R e a c t i o n M i x t u r e 96  P l o t o f Anhydride Photoproduct Composition as a F u n c t i o n o f S t a r t i n g M a t e r i a l C o n v e r s i o n  97  Pathways t o Photoproduct A n h y d r i d e 41  99  Formation  from  Figure  3.17  Photochemistry of Dibenzoyl Benzobarrelene  Figure  3.18  Characterization of Dibenzoyl Benzosemibullv a l e n e 4 2 c i n a M i x t u r e w i t h 4 2 a , b y NMR  104  Mechanisms t o Photoproduct F o r m a t i o n D i b e n z o y l B e n z o b a r r e l e n e 42  105  Figure  Figure  3.19  3.20  42  103  from  G r a p h o f Quantum Y i e l d ( $ ) o f 4 2 a v e r s u s S t a r t i n g M a t e r i a l 42 C o n v e r s i o n  106  PART I V .  PHOTOCHEMISTRY OF UNSYMMETRICALLY  F i g u r e 4.01  F i g u r e 4.02  F i g u r e 4.03  F i g u r e 4.04  F i g u r e 4.05  F i g u r e 4.06  F i g u r e 4.07  F i g u r e 4.08  F i g u r e 4.09  DISUBSTITUTED  BENZOBARRELENES  P o s s i b l e Di-7r-Methane Rearrangement Pathways f o r 2-Benzoyl 3-Ester Benzobarrelenes  110  Photochemistry Benzobarrelene  112  of Benzoyl Methyl 43  Ester  NMR S p e c t r a l E x p a n s i o n s o f Compound 43 R e a c t i o n M i x t u r e from D i r e c t S o l u t i o n P h o t o l y s i s i n C D C I 3 . . .  113  P l o t s o f Quantum Y i e l d v e r s u s C o n v e r s i o n f o r t h e F o r m a t i o n o f Compounds 4 3 a a n d 4 3 h  117  NMR S p e c t r a l E x p a n s i o n s o f t h e C r y s t a l l i n e R e a c t i o n M i x t u r e o f B e n z o b a r r e l e n e 43  119  Tri-TT-Methane Mechanism t o Form Benzosemibullvalene 43f  121  R a d i c a l S t a b i l i z a t i o n Approach to 1 , 2 - D i s u b s t i t u t e d Benzosemibullvalene Formation i n the S o l i d State...  123  X-ray C r y s t a l S t r u c t u r e Diagram D i s p l a y i n g t h e C o n f o r m a t i o n o f B e n z o b a r r e l e n e 43  124  Motions and  Required  f o r B e n z o s e m i b u l l v a l e n e s 43d  43h F o r m a t i o n  125  F i g u r e 4.10  P a c k i n g D i a g r a m f o r Compound 43  F i g u r e 4.11  Photochemistry  F i g u r e 4.12  G r a p h o f Quantum Y i e l d v e r s u s C o n v e r s i o n f o r Compounds 4 4 a a n d 4 4 c i n B e n z e n e  131  F i g u r e 4.13  C r y s t a l l i n e Conformation from X-ray A n a l y s i s  133  F i g u r e 4.14  F i g u r e 4.15  F i g u r e 4.16  F i g u r e 4.17  F i g u r e 4.18  of Benzobarrelene  of Benzoyl 45  44  o f Compound  P a c k i n g Diagram o f Benzobarrelene Intermolecular Contacts Photochemistry Benzobarrelene  127 129  44  44 S h o w i n g  Isopropyl  135 Ester 136  G r a p h o f Quantum Y i e l d v e r s u s C o n v e r s i o n f o r Compounds 4 5 a a n d 4 5 c i n B e n z e n e  139  C r y s t a l l i n e Conformation X-ray A n a l y s i s  140  o f Compound 45  from  M o t i o n s R e q u i r e d i n R e l e v a n t Di-w-Methane Holding the Carbonyl Substituents F i x e d  Pathways, 142  F i g u r e 4.19  P a c k i n g Diagrams o f Benzobarrelene X-ray A n a l y s i s  F i g u r e 4.20  PART V.  45  from 144  Table Summarizing S o l u t i o n and S o l i d S t a t e R a t i o s i n t h e P h o t o c h e m i s t r y o f Compounds 4 3 , 44, a n d 45  PHOTOCHEMISTRY  OF BENZOBARRELENE  SALTS  Figure  5.01  Photochemistry of Benzobarrelene  Figure  5.02  P h o t o p r o d u c t R a t i o s from S o l u t i o n Phase Photochemistry of Benzobarrelene Salts  Figure  5.03  NMR  Expansions  5.04  PART V I  Salts  149  150  o f S a l t 48 B e f o r e a n d A f t e r  Reacidification,  Figure  145  i n CDCI3  Photoproduct R a t i o s from t h e S o l i d Study o f Benzobarrelene S a l t s  153  State 154  PHOTOCHEMISTRY OF DIMETHYL 1,4,5,8-TETRAMETHYL-1,4-ETHENONAPHTHALENE-2,3-DICARBOXYLATE ( 4 7 )  Figure  6.01  P h o t o c h e m i s t r y o f Compound 47  158  Figure  6.02  NMR S p e c t r a ( C D C I 3 ) a n d C r y s t a l l o g r a p h i c R e p r e s e n t a t i o n s o f B e n z o s e m i b u l l v a l e n e s 47a and B e n z o c y c l o o c t a t e t r a e n e 47b  160 161  Figure  6.03  NMR  Figure  6.04  Proposed  Figure  6.05  P r o p o s e d Mechanisms t o P h o t o p r o d u c t f r o m B e n z o b a r r e l e n e 47  Figure  Figure  Figure  6.06  6.07  6.08  PART V I I . Figure  7.01  S p e c t r a o f Compounds 47 a n d 4 7 c i n C D C I 3 S t r u c t u r e f o r 47d w i t h A n a l o g y  163  Formation 165  Quantum Y i e l d G r a p h s f o r t h e F o r m a t i o n o f P h o t o p r o d u c t s 4 7 a a n d 47b i n B e n z e n e a n d i n a 1:1 M i x t u r e o f A c e t o n i t r i l e a n d B e n z e n e  167  C r y s t a l Structure of Benzobarrelene L i s t o f Bond L e n g t h s and A n g l e s  168  47 w i t h  Geometric Requirements f o r the Formation o f [2+2] C y c l o a d d i t i o n P r o d u c t s f r o m 47  PHOTOCHEMICAL  170  [ 1 , 3 ] SHIFTS I N BENZOSEMIBULLVALENES  Mechanism o f [1,3] S h i f t P h o t o c o n v e r s i o n  171  Figure  7.02  Benzosemibullvalenes stationary States  Studied  f o r Photo172  ACKNOWLEDGEMENTS  I J o h n R. his  wish  to  Scheffer,  for  novel  barriers and  ideas  sincerely his  and  thank  support  my  and  constructive  guidance  suggestions  that I never thought I could. H i s  encouragement  were  research supervisor,  invaluable  throughout enabled  endless  in  Professor  the  years;  me  t o overcome  patience,  friendship,  maintaining  my  enthusiasm  in  Garcia-Garibay  and  the program. I Dr.  would  Jianxin  research, how  also  Chen  for  answering  ridiculous  like their  they  may  day  return  favors  for proofreading this Special Dr.  Phani  Raj  thanks  in  and  from  elemental analysis Financial is  gratefully  and  be.  to  Miguel  in  the  responding  The  t o be  warm  earlier to  surroundings  i n graduate  part  ideas  school.  Anna-dora Gudmunsdottir  to  Dr.  Pokkulurl,  assistance  Dr.  of  no  matter  provided  Also,  I  and Mardy  the  by  my  hope  to  Leibovitch  thesis.  c r y s t a l l o g r a p h i c work kind  thank  assistance  questions  c o - w o r k e r s made i t a d e l i g h t some  to  James  and  this  Dr.  thesis.  the  Trotter, Ray I  Dr.  Jones  greatly  for  Steve  Rettig,  their  detailed  appreciate  the  help  staff  o f t h e NMR,  mass s p e c t r o m e t r y , a n d  the  University  of  laboratories. support  acknowledged.  from  British  Columbia  To my f a t h e r a n d m o t h e r  INTRODUCTION  I.  History The  study  of  organic  photochemistry  ago-'- w i t h t h e u s e o f s u n l i g h t a s t h e of  this  of the This as  topic  grew  mercury  meant  considerably  broad  band  that durations  arc  only  on  the  directions;  absorption  lamp  Types  of  polymer The  the  organized  a  dramatically  stereoisomers  of  to more  by  widely  in  common  first  photochemical  f r o m ammonium c y a n a t e i n a t h e r m a l  spectroscopy,  respect  means,  ago  technique;  organized  with  infrared  crystallography.  i n  studies  chemical term  the  and  systems  to  the  from  crystals, monolayers. is  state,  regioisomers  though  to  processes. organized  i t i s currently synthesized  state reaction.-^  did of and  their  solution  o f a r e a c t i o n i n an even  i n an subject.  are  micelles,  not  bloom  nuclear most  crystallography of  of  i n  interaction  reaction  to bimolecular  solid  development  X-ray  expanding  1828, F r i e d r i c h Wohler  media  spectroscopy,  Modern  o v e r c o m e two b a r r i e r s  the  in  still  m e d i a . ^ The  these  example  urea  years  source.  o f p h o t o l y s i s depended  i s  formation  most  in  light  photochemistry  to  with  the  Research  a  cyclodextrins,  alter,  the  used  popularity  o f t h e compound b u t o n t h e  definitive  photoproduct  Interestingly,  thirty  cause  as w e l l as from u n i m o l e c u l a r  not  lengths  reactivity  used  zeolites,  selectivity  medium was  is  characteristic  to  The  artificial  Organic photochemistry  media  matrices,  ability  an  to this,  and  molecules  environment  unique  as  one i s i n t h e r e g i o n o f o r g a n i z e d  of photons w i t h organic anisotropic  source.  o f p h o t o l y s i s were r e d u c e d t o m i n u t e s a n d h o u r s  weather and season as w e l l . many  irradiation  i n t h e e a r l y 1900s w i t h t h e development  opposed t o days and weeks. P r i o r  not  b e g a n a b o u t two c e n t u r i e s  photochemical  until  magnetic  resonance  importantly, allows  about  chemists  X-ray to  structure-reactivity  relationships. structures.  The  The  first  second  is  and  more  v i s u a l i z a t i o n o f the m o l e c u l a r Of work has in  a  the  various  b e e n done  crystal  close-packed repeating  with  are  each  unit  of  constraining  use  of  in  cell as  lattice  would  so  as  the  lattice  remains  the  Ciamician, progress since  stage  of  organic and  state as  This  many  is to  that,  ultimately,  main  molecule  applications  science,  II.  the  The  and  the  the  detailed  the most  extensive  phase.  Molecules  and  they  cases,  molecule  are  the to  feel  thus  have  as  a  fully  the  fact  cannot  be  dependent  study  scientists  Senier.^  Although  advanced  recently  in  of  influence  pioneering  has  the  that  photochemistry  to  the  like the  considerably  been  published,^  synthetic  crystal  predicted.  asymmetric  was  "discover-and-explain"  predictive  of  same  reacting  field  and  the  the  This by  evenly  systematic  intact.  still  areas  that  environmental  is  to  medium in  in  same  articles  used  primarily  unique  most  century  photochemistry  due  manner  state photochemistry  review  opposed to b e i n g  photoproduct  the  Stobbe,  solid  use  neighbors,  feel  twentieth  Kohlshutter,  then  solid  early  a  each  its  the  in  its  of  crystalline  For  allows  in  opened  the  such  molecule long  is  media represented,  neighbors.  environment  confirmation  vital  organized  organized their  the  reaction cavity.  the  among  in  tool.  packing  It  is  is  thought  will  have  synthesis,  its  materials  computers.  Excited  There  State  are  a c o m p l e t e summary  many would  aspects fill  this  text.  molecular The  excited  following  state,  will  and  briefly  touch  relevant  areas  reviews can be found i n p u b l i c a t i o n s by  Turro^  in  on  a  some  of  t h e more  molecular  electron spin radiation,  (SQ). an  ground  Upon a b s o r p t i o n  electron  (HOMO) i s t r a n s f e r r e d (Figure state the  0.01).  state  from  exist ofa  This  excitation  (Sj^) ;  spin-orbit  unpaired  triplet  coupling excited  unoccupied  state  (T^^) .  o c c u r f r o m e i t h e r t h e Sj^ o r Tj^ e x c i t e d  Figure  energy of  intention  photons  broad  band  of  according  occupied  or  molecular  their  visible  molecular  orbital  orbital  (LUMO)  i n the s i n g l e t excited  electron  to spin  Most p h o t o c h e m i c a l  the photochemist  i s to  irradiate  flip  to  reactions  with  low  t o s e l e c t i v e l y e x c i t e a HOMO e l e c t r o n  t o t h e LUMO. The u s e  high  t h e HOMO  energy  photons  would  excite  lower  to s e l e c t i v e l y e x c i t e .  HOMO  /  LUMO  to  other  a c a s c a d e o f d e c o m p o s i t i o n modes.  Conjugated molecules o r molecules that possess heteroatoms with have  to  Transitions.  u n o c c u p i e d o r b i t a l s ( S 2 , S 3 , ...) c a u s i n g  electrons  Electrons  states.  0.01 E n e r g y D i a g r a m f o r S e l e c t e d  The  Detailed  Mayo^.  ultraviolet  puts the molecule an  topic.  a n d de  photon,  allows  this  i n pairs  the highest  t o the lowest  of  non-bonded  e n e r g y gaps a n d a r e t h e r e f o r e  easier  LEGEND Absorption Internal conversion Fluorescence SINGLETS Intersystem Crossing IC TRIPLETS  Phosphorescence  ISC  ISC Singlet Reaction  /  IC * \  hv  Triplet Reaction  ZI /  F i g u r e 0.02  In release.  Energy Diagram f o r General  S i  the  They can a)  state,  molecules  have  several  Processes.  methods  of  energy  energy  triplet  undergo:  Intersystem state  Molecular Photophysical  crossing  (T]^) ; t h i s  - spin f l i p  i s forbidden  but  to the occurs  lower  through  spin-orbit  coupling. b)  Fluorescence back t o SQ; 10^  - r e l e a s e energy i n the  t h i s process  - l O ' ^ ^ sec-1.  i s allowed,  form o f l i g h t and  and  occurs  at  a  return  rate  of  c)  Internal  conversion  o f h e a t and two d) Molecules release.  states  return are  t o SQ",  the  the  They can a)  (T]^)  state  to  - release  SQ;  this  spin-orbit coupling  heat  and  energy  is  spin  - release  return  c) R e a c t i o n t o g i v e  t o SQ;  in  yield  of  the  energy  form  of  but  lO"-*- - 10^  light  occurs  through  sec'-'-.  v i b r a t i o n a l energy i n this  and  the  i s spin forbidden  but  form occurs  coupling. photoproduct(s).  ($)  Once  a  molecule  is  that  a  selected  decay  yield.  The  sum  equal  one.  0.02,  the  Figure  "^internal  of For  energy  excited  usually  processes  is  phenomenon transfer  i f  is  yields  a  of  are  shown  in  efficiency.  the  probability  defined  by  for  a  is  in  molecule  t o one.  process  state,  '^reaction-  the  quantum  defined  S i state  the  ^intersystem  state of  crossing'  However, c h a i n - r e a c t i o n  processes  one. worth  (triplet  energy  taken  quantum  add  than  measure  excited  route  ™ust  the  an  ^flourescence•  triplet  occurs  in  example,  have v a l u e s g r e a t e r  (T]^-T]^)  is  possible  conversion  Another  of  spins  0.02. Quantiim  can  the  disallowed  T h e s e commonly e n c o u n t e r e d p h o t o p h y s i c a l  must  the  a l s o h a v e s e v e r a l modes o f  at a rate of  Intersystem crossing  through s p i n - o r b i t  Figure  as  undergo:  return  of  i s allowed  form  photoproduct(s).  triplet  Phosphorescence  b)  this  v i b r a t i o n a l energy i n the  same.  R e a c t i o n to give in  - release  from  intermolecularly  mentioning  is  sensitization). one and  system a  few  to  with  triplet-triplet  This  i s the  another.  criteria  The  m u s t be  transfer process  satisfied.  Firstly, than  the energy l e v e l o f the  the  acceptor  triplet.  excited  donor  Secondly,  the  p h y s i c a l l y come t o g e t h e r f o r e n e r g y t o second donor  factor  is  ultimately  transfer.  dependent  0.03  on  Keller  et  intramolecularly efficiency  to  of  were  in  system  studied. the  chromophore  then  transferred  energy  where  transferred  benzoyl  effect  The  (4)  Compound  only  system  higher  acceptor  efficiency  collision  must  of  rate  triplet  investigated  the  transfer.  that  naphthyl  1968  determine  energy  be  the  o f the  donor.  (3)  and  a  Donor-Acceptor System ( 4 ) .  a l . ^  benzophenone-naphthyl systems  and  The  the  must  l-Benzoyl-4-(a-naphthyl)-bicyclo[2.2.2]octane  R i g i d Benzophenone-Naphthalene  of  donor  t o the a c c e p t o r and the l i f e t i m e o f the e x c i t e d  Figure  such  triplet  of  was  group i t s  distance  energy was  was  to  0.03),  photolyzed  was  phosphorescence determined  energy  benzoyl-naphthyl (Figure  3  this  (A  excited  be  100%  on  the  system  (3),  and  other  >  350  (n-7r*) ;  through observed.  transfer  space The  with  nm) the  to  the  efficiency a  calculated  7  s e p a r a t i o n between the of of  compound the  4  was  of  the  sensitization  through  distant  III.  The  in  of  of the  so  named  by  an  sp^  This  is  material, Simple product  closure More to  medium  in  concluded.  also  and  in the This  recently  studied  Â.^  is the  subject  the  with  He  di-7r-me thane  the  or  of  proposed ^°  of  the  of  of  simplest  thesis. two  The  w-bonds  representation  of  di-7r-methane  0.04.  a s t e p w i s e mechanism w i t h an g^^^  b,  the  carbon. A  cyclopropyl  by e i t h e r b o n d c l e a v a g e o f a, of  rearrangement.-*-^  presence  "methane"  one  ^'^^  reaction  required  proceeding  biradical  recently,  this  benzonorbornadienes.  efficiency  t r a n s f e r was  (6),-'--'- i n F i g u r e  cleavage  6c.  alternative  is  shown  followed  ring  35% was  decrease  rearrangements  Zimmerman-*-^  or  the  thoroughly studied unimolecular  from  b o n d f o r m a t i o n a c r o s s Q,^ 6a.  to  space  KBr  phosphorescence  sensitization  hybridized  1,4-pentadiene Howard  state 12  most  this  is  energy    A  group  the  photochemistry  reaction  systems,  state  group. 15  benzophenone  the observed  compared  ca.  solid  was  separated  a  The  Rearrangement  the  variation,  reaction  a  Di-TT-Methane  organic  Without  over  d e t e r m i n e d t o be  One  was  benzophenone  excited  by G a r c i a - G a r i b a y i n  acceptor.  e x c i t e d and  moiety  triplet  d i s t a n c e was  and  selectively  naphthalene  phosphorescence  donor  6b  gives  Paquette-*--^  mechanism  based  suggested  a  on  [1,2]  his shift  intermediate  g i v i n g back  to  initial  starting  1,3-biradical  6b.  the v i n y l c y c l o p r o p a n e proposed study of  a of  one  viable  substituted unsaturated  group  followed  between  this  formed state  in  by  mechanism  only  in  one  Figure  biradical  6a  intermediate;  ring  and  step  0.04. is  closure  to give  the  Zimmerman's  is  instead  At  this  simply  a  of  product. that  two,  point,  as  i t  a l s o i n some c a s e s ,  the  steps  only  and may  difference  biradical  shown b y  can  representation  The  only  the  be  may  to  is  transition  stated  not  merge  6b  be a  that  a  true  concerted  process.  Figure  Di-7r-Methane Mechanisms R e p r e s e n t e d  0.04  The on  the  multiplicity  type  di-TT-methane  of  of  this  di-ir-methane  rearrangement  reaction  system.  efficiently  singlet  acyclic  systems  their  efficiently  than t h e i r  triplet  states.  found  to  compounds  through  i n e f f i c i e n t l y through t h e i r via  is  Cyclic  s t a t e and  rearrange  i n 1,4-Pentadiene  their  s t a t e s . On singlet  be  (6).  dependent  undergo triplet  the  excited  the  excited  other states  hand, more  Compound 7 ( F i g u r e direct  photolysis  vinylcyclopropane the diene  8  triplet  Figure  results  7a.  trans-isomer  is  in  Alternatively,  in  rearranges  0.05)  a  upon  reversible direct  a  a  typical  example  di-7r-methane triplet  but  is  s e n s i t i z a t i o n . •'-^  0.05  Examples  of Acyclic  Di-w-Methane  Systems.  the  rearrangement  sensitization  photostationary  photolysis  to  of  s t a t e . •'•^ not  7  rule; to gives  Likewise,  reactive  from  Barrelene that  (9)  (Figure  rearranges to bullvalene  However,  when d i r e c t l y  followed  by  a  upon Direct  triplet  r e v e r t s back  (10)  excitation  photolysis  (9a)  upon  is  a  cyclic  yields  ring  opening  also  undergoes  to  give  to  give the  the  the s t r a i n e d  di-?r-methane  triplet-sensitized  i r r a d i a t e d , b a r r e l e n e undergoes  thermal  Benzonorbornadiene  0.06)  photolysis.-^^ cycloaddition  cyclooctatetraene  di-w-methane  tetracyclic [2+2]  [2+2]  compound  10a.^'^  product (10b), which r e a d i l y  to s t a r t i n g m a t e r i a l .  (ref.  0.06  (9b).  rearrangement  (ref.  Figure  system  Examples  of C y c l i c Di-7r-Methane  Systems.  19)  20)  The basis  of  multiplicity difference in reactivity  the  "free-rotor"  effect.Acyclic  through t h e i r t r i p l e t e x c i t e d permitted back  in  to  non-rigid  their  systems  deactivate  rearrangements. have  been  compounds  that  because allows  states  (Sg).^*^  more  slowly,  Although  reported  states  structures  ground  the  rule  instances  rearrange  where  through  t h a t the back by  to  first  earlier  in  intermediate  starting  Zimmerman.^^^^  material. He  the  can  concluded  situations  most  the o p p o s i t e  e x i s t s w i t h the Initial  same  was  singlet  mechanism  bonding  can  study  to  than  bonding i s  most  stable  intermediate  energy  most  likely  be  s t e p of the  lower.  In  the many  there  i.e., cyclic states  and  cases,  formation  product  or  was  revert  i n a review  barrelenes  that  be r e v e r s i b l e .  di-T-methane  arises  for  sites  selectivity.  giving  usually  system  different  directed  to  the  b a r r i e r t o i t s f o r m a t i o n would this  is  the  rearrange  from  rate-limiting  rearrangement.  Compound  11  (Figure  benzo-benzo bonding or i n i t i a l pathway  true,  azo  one  different  p h o t o p r o d u c t s . However, t h i s i n i t i a l as  efficient  i s discussed of  opportunity  from  rigid  cases,  product  proceed  a  more  occur  of  excited  to  reversibility  chromophore,  deactivation  states.^-^^  from  where  twisting  states  t r i p l e t - m e d i a t e d di-x-methane rearrangements tend t o not In  bond  facilitating in  the  rearrange  for fast t r i p l e t triplet  on  do not  double  thus  either  This  the  The  their  explained  systems  applies  a c y c l i c compounds through t h e i r t r i p l e t Mentioned  was  interferes  with  the  0.07)  can  benzo-vinyl aromaticity  o f two ring  However,  the  initial former  p h e n y l r i n g s as opposed  t o the d i s r u p t i o n of  only  one  bonding.  with  the model, photoproduct l i e i s the o n l y  Consistent  aromatic  bonding.  either  occurring  in  benzo-vinyl product  observed.  This r e s u l t exemplifies  which  disruption  the  Alternatively, route on  through  12a  ester  can 13  of  over  delocalize (Figure  competition  aromaticity  cyclohexadiene 12a  the  disfavors  derivative  12d  on  through  0.07)  the the  has  12  (Figure  aromatic  from  the  paths t o two, w i t h on  the  stabilized  list initial  unsubstituted by  the  of  ester  b u l l v a l e n e 13c as t h e o n l y  choices.  but not t h e o t h e r . 0.07)  ring.^*^  selects  initial  the  radical  Dibenzobarrelene  bonding  bonding  on  The  path  through  carbonyl,  is  preferred,  product.  in  possibilities. bonding  may  be  T h i s reduces t h e number o f i n i t i a l  benzo-vinyl  side.  pathways  that the benzyl  initial  Based on t h e r e s u l t s o f compound 11, benzo-benzo excluded  one  rationale  four  between  the 13a,  ester with  giving  side a  or  radical  dibenzosemi-  Flgure  0.07  Di-TT-Methane  Examples  the  Initial  Bond  Formation  Selectivity  in  the  Rearrangement.  Selectivity in  of  initial  of  step.  the  rearrangement  Interestingly,  in  i s  not  solely  incorporated  the second b i r a d i c a l  formation  of  Zimmerman's  opportunity  mechanism, for  the  selectivity.  f a v o r e d r e a c t i o n pathway i s on  the  bond-breaking  relative  as  energy  The  theory  follows:  levels  of  the  the  the  bond  cleavage  theory  that  will  radical  provides  for  bond  two  F r o m Zimmerman's n o t a t i o n , t h e more s t a b l e o f from  step  predicting  broken  is  branch-point  the  another  two  the  dependent  p r o d u c t s . •'-^  biradicals  formed  b e p r e f e r r e d . The b a s i s o f t h i s  rule  stems  from  stability  efficiency  of  is  dependent  on  TT-delocalization. The  proposed  intermediate  14a  (Figure  0.08)  e x c i t a t i o n o f 14 c a n c l e a v e a n y one o f t h e t h r e e b o n d s a , bond a  c  i s broken then  or b i s cleaved,  In  14a,  radical is  owing  i s less  cleaved  for  thorough step  reaction  will  delocalization  give  than  investigation  proceed  through  to  the  previous  7a  example,  i n h i s study. aromatic  ring  some  substituent  reduces  is  electron para  characteristic the a b i l i t y  photoproduct  the  many  A methoxyl group i n the  i n the ortho or  donating  of  p-15b  of  of the  from  ring,  effects  acyclic meta  withdrawing, position) the aryl the  para  of  position  acts  as  b  favored  di-7r-methane  the  forth  bond  0.08)  1,4-dienes a  a  cleavage  15 ( F i g u r e  of  used  disubstituted  involved  an  bond  1,4-diene 7  put  series  i f  the benzyl  7c  the only  substituted  but  products.  As a r e s u l t ,  Zimmerman  If  b u t i f bond  biradical  is  i n the di-7r-methane r e a r r a n g e m e n t . C o m p o u n d only  c.  or  respective  phenyl  proposed  photoproduct  into  b,  1 4 c a s t h e o n l y p r o d u c t . ^ 3 xhe  t o bond a o f t h e  the  from the  be r e g e n e r a t e d ,  the cyclohexyl r a d i c a l .  compound  Consequently,  Including  represents  (i.e.  to  i s similar  cleavage.  product.-*-^  the  reactive  to  ( F i g u r e 0.05)  starting material w i l l  formed  i n resonance  electron  donor.  The  s u b s t i t u t e d m e t h o x y l group o f p-15a  radical homolytic  to  delocalize.  cleavage  of  As bond  a  result, a  occurs  w i t h about three times of  bond  b.  On  t h e e f f i c i e n c y a s compound p-15c f r o m  the other  hand,  e f f e c t o f the methoxyl group the  aromatic  phenyl  o f bond  b  i n t h e meta  i n m-15a  chromophore i s l e s s  cleavage yield  radical  stable  over  the inductively  bond  over  position  the breaking  electron-withdrawing slightly  stabilizes  the unsubstituted phenyl.  causing  a  slight  preference  Now t h e for  the  a. R e s u l t s show a m-15c t o m-15b q u a n t u m  r a t i o o f 0.086 : 0.072.25  He ( r e f . 23)  15b  ( r e f . 25)  c-cleave/\  Ar  Ph Ph  Ar ArPh Ph  15c  15a  15  0) a-cleavage product  0) b-cleavage product  PJ5  (Ar = p-MeOPh)  0.075  0.022  m-15  (Ar = m-MeOPh)  0.072  0.086  F i g u r e 0.08  Examples  of  Dl-;r-Methane R e a r r a n g e m e n t .  Secondary  Bond  Cleavage  Selectivity  i nthe  IV.  The  Topochemical  This chemistry are in  of  concept  originated  which  on  the  before  modern  the  molecules this  exist".  postulate  X-ray  techniques.^''  allowed  them  to  reactivity.  solid  establish Of  the  the most i n t e r e s t i n g Unsubstituted  that  (a,  i t  /8,  and  7).  up.  the  the  two  the  range  [2+2]  parameters  study  double of  bonds  by  ;3-form p h o t o l y z e s between  3.9-4.1    to give Â.  from  crystalline  product  adduct The  analysis 5c  7-form  for  solid  et a l . ,  of a  the  (Figure  packing  0.09)  arrangements  acid i n solution results  5b. was  with on  results  Schmidt  a c i d (5) i s t r i m o r p h i c  (center-to-center)  3.6-4.1  X-ray  o f t r a n s - c i n n a m i c acid.-'-^  trans-cinnamic  cycloaddition  co-workers  modern  i n c i s / t r a n s i s o m e r i z a t i o n ; whereas p h o t o l y s i s o f c r y s t a l s gives  forty  experimental  is their  of  solids  introduction  and  using  reinvestigated  known  in  over  the  Schmidt  state  environment  just  With  systems  three  Photolysis  took  fundamental  trans-cinnamic  possesses  i t  accumulated  some  solid  dimensional  reactions  The  of  "reactions  three  Gerhard  state  days  that  followed  crystallography,  crystallographic  in  early  However,  was  many  perhaps  the  constraining  reinvestigated  state  in  w h e n K o h l s h u t t e r ^ ^ p r o p o s e d i n 1918  dependent  years  Principle  The  of  the  distance  established the  to  unreacted  reaction other  between be  crystal.  distance  hand,  a-form  is  in The  ranging  unreactive  a s t h e d e t e r m i n e d s e p a r a t i o n i s b e t w e e n 4.7-5.1 Â. Without p r e j u d i c e to the s o l i d dependent  chemistry  Kohlshutter  a n d r e v i t a l i z e d b y S c h m i d t . •'•^ As  theories  later  relies  discussed  on  this  state,  almost  principle i t will  a l l modern  initially be  a r e b a s e d on t h e T o p o c h e m i c a l  media-  proposed  s e e n , many Principle.  of  by the  Ph \ —  Ph "^COOH  COOH  ^Solution  ^  Ph  Ph  HOOC^^^^^^ \ Ph  hv  COOH  HOOC  ~ a-form  ^  ^  5fe  ^\  ( COOH | Ph  Ph  Ph^ \  \oo„  —  1 / ^ f 1COOH  p-form  COOH  5c  Ph HOOC  ' \  hv COOH  •  \  d >  Figure  0.09  Crystalline  Photochemistry States.  NO REACTION  T-form  of  4.7  Trans  A  Cinnamic  Acid  i n Solution  and  V.  S o l i d State  Reactivity  Throughout the  organic  the h i s t o r y of  crystalline  chemistry,  phase  easily  handled,  of c r y s t a l s  form.  a r e u s e d i n compound  appearances their  inert  and  melting  In  accepted  role  in  that  chemical  c r y s t a l l o g r a p h y , 29 scanning  and  stored  reactions.  parallel  resolution  manner, t h e  properties  through  in  that  manner  every  is  classification space  is  groups  a  chiral opposed  chiral  of space  to  a  classified called which group  symmetry,  65  are  feels  symmetrical  have c h i r a l A molecules  space  achiral  is  becoming  play  of  an  active  modern  X-ray  •'-•^C NMR,-^^ d i f f e r e n t i a l the  probe  into  solid  the  same  repeating  unit  its  group".  same  molecules and  230  this  possible  repeating  unit  unsymmetrical  environment  As  crystalline  groups  molecules  of  are  Each  stacked  intermolecular  symmetry,  There  chiral.  environment. space  systematically the  to  internal  a  result,  due  usually  to do  their  inherent  n o t b u t may  also  groups.  molecule from  and  feels  The  "space  m o l e c u l e s must a d o p t c h i r a l of  are  according  the  be compared t o  i t  also  different  i s governed i n p a r t by the  crystal  .  their  findings.  molecule  e n v i r o n m e n t , b u t e x c e p t i o n s do e x i s t cell)  state  techniques,  f a c i l i t a t e d many new  a  can  Compounds crystals,  advent  solid  other  Molecules i n  (unit  the  e x t e r n a l c r y s t a l appearance  a  phase  With  p a c k i n g arrangement. such  recognized  as  known compounds may  crystalline  calorimetry,and  The  lack  a  often  identification  points,  the  high  s t a t e c h e m i s t r y has  as  are  l i t e r a t u r e v a l u e s f o r s t r u c t u r a l c o n f i r m a t i o n . Now  well  in  have  a s a means o f r e a c t i o n w o r k - u p .  c a n be p u r i f i e d b y r e c r y s t a l l i z a t i o n a n d an  scientists  within  infringing  a  crystal  on  i t  by  lattice basic  steric  prevents  neighboring  interactions.  This i s  where the  atoms o f  charges  and  designed energy can  minima.  Within  1975, the  from r e a c t a n t by  the  in  geometry  Cohen-^2  incompatible  with  (path from the  The selectivity  of  will a).  occur  other's  these  interactions  molded  to  space, space the  suggested  geometry  each  of  one  solid  Figure  proceed However, the  0.10.  without  This  molecule  its  has  conformational  state photochemical  reactions  "reaction cavity".  that the  Cavity.  as  a  molecule  species  reacts  changes w h i l e This  much  reactions  interference  with  is  i n turn w i l l  be  slowed  give r i s e  the  state or  changes cavity  geometries  even  to r e a c t i o n  a  represented  from  transition  in  proceeding  Those r e a c t i o n s w i t h m i n i m a l  reaction cavity will  b).  electrostatic  the  of  through t r a n s i t i o n s t a t e ( s ) to product.  structures  differing  this  physical  (path  to  volume o f space,  feel  Cohen's Concept o f the R e a c t i o n  In crystal,  molecules  Through  Cohen termed t h i s  F i g u r e 0.10  walls  repel.  i t s own  occur.  adjacent  forbidden selectivity  s o l u t i o n phase.  underlying differ  from  factors reactant  responsible to  reactant  for  crystalline  depending  on  state specific  interactions either of  be  a  of the direct,  substrate  where  the  properly  where  lattice for  reaction  e x p l a i n any  the  by  the  an  correlation"  is  employed by  leading solid  s t a t e p h o t o c h e m i s t s s u c h as  ketone  a study  16  photolyzes  Alternatively,  from The with  a  as  by  the  radical  the  Scheffer in  photolysis only  three-step  Cg  commonly  C2-C3  to  in  crystalline  the  product.  give  Compound  initial  16a,  double  i t was  benzene  process,  on  et al.,-^^  derived the  product  owing  bond,  (16c).  from i n i t i a l  hydrogen  4,5-bonding  atom is  C4  understanding  structure  data  is  i n t e r a c t i o n s to  This  "structure-  Lahav,-^-^  on  Cy  bonding, by  over  the  initial  biradical  McBride,-^^  to  form  the  C5  bonding  C2  to  to  give to  solid by  radical.  C2-C5  the  to  come  give  16a.  in  It  to bond  and  yielding  the the  s t a t e p r o d u c t 16e  is  the  of  abstraction  was  solution  such  alignment  16b,  C3  16c.  tricyclic  conformational  the  proceed  diketone  postulated  of  s y s t e m ; "^^ to  was  followed  C2  ;S,7-unsaturated  phase g i v e s  with  3,5-bonding  formation  needed  tetracyclic  its  Alternatively,  to C5  found that  to  to  bridges  oxa-di-7r-me thane  is  motion  an  C3  favored  reactant  large  required  used method o f a n a l y s i s ,  16c  rearrangement i s completed w i t h a 1 , 2 - s h i f t solution  atoms  Ramamur t h y . ^ ^  In  i s o m e r 16e  most  to  formation.  reactivity  S che f f e r , 3 5 and  the  product  indirectly,  the  steric  may  movement  group of  in  crystal  or absence of s p e c i f i c  retarded  or  approach  X-ray  the  or  atom  molecule  this  reactant  interactions  reaction,  positions  in  These  group i n h i b i t s  for  locking  the  or  lattice  required  presence  enhanced  lattice.  specific  Consequently,  for  the  geometrically  state selectivity,  examined  a  appendage  conformation. solid  substrate with  reasoned  that  because  the  systems e a s i l y 16c. forbids  undergo  However,  the  continuation  of  this  reaction  r o u t e has minimal  i n  the  crystalline  topochemical  phase.  requirements  The  initial  3,5-bonding  and i s t h e r e f o r e allowed.  Me  (ref.  I  F i g u r e 0.11  It in  Solid  State  Reaction.  i s n o t uncommon f o r a compound t h a t i s r e a c t i v e p h o t o c h e m i c a l l y to  state  is  converted  or  have  be  Me  Example o f a U n i m o l e c u l a r  solution  solid  37)  an  unreacted  be  reactive  photoproduct to  product  enhanced due  to  in  in  solid  conversion the  ability poor  the  lattice, to  photon  absorb  phase  is many  limited. reacted  light,  penetration  as  then  through  well.  Usually  As  molecule  a  species the the  retain  bulk  will  crystal.  Another is  common  reacted,  different the to In  from  most  new  the  bulk  molecule  defect  and  cases, cracks,  to  reactant  This  surface  forming This  this  lattice. the  deterrent  has  and,  promotes  inhibits  the  prolonged becoming  crystal. recent  band  to  cloudy,  facilitate  This bulk versus  a as  a  the bulk  and  t h a t once a  the result  of  penetration  reactivity  has  light  crystal  from  in  the  melting  by i r r a d i a t i o n  geometry  generates a defect i n  scattering of  substrate  dimensional  result,  even  deeper  surface  is  three  photolyses  problem i s p a r t i a l l y a l l e v i a t e d  absorption  reactivity  in of been  reacting. crystal  on  the  the  tail  light  back  surface. of into  discussed  the in  a  s t u d y by S c h e f f e r and co-workers.-^^ Upon  irradiation,  photoproduct without  loss  i s known as a " t o p o t a c t i c "  some c r y s t a l s of their  can convert  crystalline  or single  completely  appearance. This  crystal-to-single  crystal  to a  11  0.12  Photodimerization  lia  of  Benzylidenecyclopentanone.  single  phenomenon reaction.  (ref.  Figure  the  41)  Of the most  the commonly  reaction.  In  to  the  [2+2]  favorable  et  [2+2]  i n the complete  17a  with  the  analyses  in  crystal  by  of  compounds and  starting molecular  17  cell  pentanone  state  Photolysis  conversion of  packing  interconversion of  17.  retention  of  far  cycloaddition  al.'^-'- s t u d i e d t h e s o l i d  benzylidenecyclopentanone  adduct  similarity  processes,  intermolecular  Thomas  Crystallographic  r e v e a l a remarkable for  and  of  photochemical  the  compound 17 r e s u l t s  crystallinity.  allowing  is  Jones  behavior  crystalline  material  bimolecular  observed  1980,  photochemical of  known  and  17a  dimensions  derivative  17 t o  p r o d u c t 17a. Asymmetric organic crystal an  space  state. groups  asymmetrical  generate may  solid  a  synthesis  possess  chiral a  solid  another  mentioned  environment  new  influence  As  is  the  center(s), state  earlier,  chirality. on  0.13  Enantioselective  D l i s o p r o p y l E s t e r 18.  Chiral  molecule. this  to  65  of  the  study  the  crystal  of  possible  lattices  the 230 exert  For p h o t o r e a c t i o n s which  temporary  lattice  chirality  r e a c t i o n i n s u c h a manner t h a t t h e p r o d u c t  acquires this c h i r a l i t y i n enantiomeric  Figure  aspect  excess.  Phototransformation  of  Dibenzobarrelene  Molecular a chiral  space  chirality  group.  dibenzobarrelene  is  Scheffer,  18  has  the  group  two  P2]^2]^2]^ a p p e a r . Pcba  through  the  this P2]^2]^2]^  is  with  morphology;  Figure  benzo  from obtained.  space  to  18  The  noticed  that  Recrystallization  group  Pcba.  in  solution  interesting  crystal  to  the  direction  in  photolysis  formation  of  the  the  bonding the  obtained;  anterior  of  reactant  single  optical  and,  benzo  on  group  However, space  or  in  i f to  the  the  on  (dotted  the  of the  of  18a  rotation  a  (Figure latter  line)  the  of  chiral  with  100%  varies  from  crystal  chosen.  initial  bonding.  M  side  bonding vinyl,  aspect  of  of the molecule  analysis  lattice  the M s i d e bonding  location  forms  vinyl  Crystallographic  crowding leaving  is  of  leads  The  initial  group  the  the  differ  i f  enantiomer  while  achiral  on t h e handedness o f t h e c h i r a l  pathways 0.14,  anterior  steric  the  rearrangement.  this  excess.  to run depending  reaction  is  co-workers^^  into  g i v e s a r a c e m i c m i x t u r e o f d i b e n z o s e m i b u l l v a l e n e 18a  di-7r-methane  enantiomeric  side  crystallization  c r y s t a l l i n e morphologies.  Photolysis  crystal  study  one  and  for  compound i s c o o l e d f r o m t h e m e l t , c r y s t a l s h a v i n g t h e c h i r a l  single  run  mandatory  Trotter,  from e t h a n o l gives prisms w i t h if  not  the  from  (dotted  is other 0.14)  The  on  In the  line), the  P  enantiomer shows  the  b o n d i n g r o u t e (P  side)  relatively  open.  F i g u r e 0.14  L a t t i c e Environment of Dibenzobarrelene  Through sophisticated  energy and  advancement  calculations  understanding Mechanics  the  are  computer now  hardware  possible  (MM2)  calculations  conformations  in  programs  h a v e o p e n e d a new  allowed  molecules  that  stem  from  to  this  theories  in  the  Molecular  locate  design, molecular  passage to the f o r m u l a t i o n of  in  the  intermediates.^-^  18.  software,  assist of  chemists  and  and  to  of molecular processes. A l l i n g e r ' s design  II  other  of  Diisopropyl Ester  minimum  From  this  calculations solid  state  reactivity. In  a  three parameters phase  publication,  u s i n g the  dimensions,  directly  following  branch-point was  and  species).  calculated  the  the  and  program*^^  to  Zuraw'^'^ predict  established crystalline  Concerned were the s t a r t i n g m a t e r i a l geometry, geometry  branch  Change i n by  Zimmerman  MacroModel  reaction selectivity.  lattice  This  recent  of  the  intermediates  p o i n t i n the r e a c t i o n pathway motion  superimposing  (AM)  was  the  the b r a n c h - p o i n t  first  or  products  (termed  the  parameter.  intermediate  over  the s t a r t i n g m a t e r i a l distances. efficient  and  adding a l l the non-hydrogen  Intuitively, the s o l i d  parameter.  The  the  state  larger  reaction.  branch-point  Therefore, third by  species  small  was  AV  species  is  values the  superimposing  the  branch-point  with  the c r y s t a l  of  the  lattice  species. crystal  of  m u s t be  enough  to  AS  values  favour  performed  give  encouraging  needed to b e t t e r e s t a b l i s h  Photochemical  These The  and  movement o f t h e  chains  are  be bond  numbered  bond. S y s t e m a t i c a l l y  x  and  y  the r e a c t a n t  volume  of  reactivity.  the  amount  r e c o r d e d as The the  a  entire  state  molecule  of  volume  The  determined  reactant  wherever  overlap  percentage of  lattice  superimposed  reactivity.  X-ray  possible.  These  of unsymmetrical  of this  are  more  di-7r-methane  examples  are  approach.  reactions  along  a  from denote  the  a sigma bond i s carbon  chain.  t h e r m a l l y or photochemically.  in  the  where  conjugated  either  described  starting  next  Shifts  initiated is  The  however,  the g e n e r a l i t y  the  o f the r e a c t a n t volume.  the  solid  used  results;  elsewhere  can  over  contain  series  rearrangements  reformed  reactions  a  [1,3] S i g m a t r o p i c  Sigmatropic cleaved  on  was  ( A S ) ; t h i s was  used.  large  were  less  over  state  reactant.  segment  coordinates  were  species  t h e n c a l c u l a t e d and  lattice  small  structure  to  was  solid  interference  the  the  non-overlapping  favor  lattice  removing  lattice  Again,  calculations systems  and  volume  segment c h o s e n  VI.  should  was  the  the  displacement  sum,  (AV)  superimposed  r e p o r t e d as a p e r c e n t a g e  parameter  in  displacement  Volume r e q u i r e m e n t  i n a c a l c u l a t e d b e s t f i t geometry and branch-point  the  atomic  a  atoms  [x,y]  notation;  adjacent  positions  to  along  the the  the  two  broken chains  w h e r e t h e new b o n d i s f o r m e d . are  thought  to  be  Such  concerted  thermal  pericyclic  and  photochemical  processes  reactions  whereby  the  bonds  f o r m a n d b r e a k s i m u l t a n e o u s l y w i t h no d e t e c t a b l e i n t e r m e d i a t e s . A set of orbital  symmetry  Hoffmann^^  f o r predicting  and  disfavored.  which  molecular is  orbital  configuration, activation promoted  (HOMO).  (Figure shifts  shifts  must  this  symmetry  the  0.15).  next Now  to proceed with  predictions,  the  retention  a  occur thermal  same  match.  orbital  by  symmetry of  the  Woodward  as  is  the  inversion  of  Photochemical a  symmetry  of  electron  [1.3] In  also  shift the  scenario;  should  [1,3] of  satisfied.  allows  occupied  symmetry  through  configuration.  configuration  the  the  and  are favoured  highest  reactions,  different  the  HOMO  sigmatropic  light occur  is  of  these  w i t h [1,7]  photocheraically and [1,5] s h i f t s t h e r m a l l y .  HOMO of ground state  F i g u r e 0.15 of  from  However,  altering  orbital retention  proposed  surface  requirement  slightly  of  was  s i g m a t r o p i c rearrangements  In  lobes  involves to  which  Transitions  forbidden to occur along  interacting  rules  Symmetry  Diagrams  HOMO of excited state  Describing  O r b i t a l Overlap f o r [1,3] S h i f t s .  the  Woodward-Hoffmann  Theory  As as  concerted  shifts set  mentioned  there  earlier,  pericyclic  reactions;  have  many  been  o f examples has been found  Irradiation  disproportionation  the  21b  through  [1,3]  shift  reaction.'^^  i n a-cleavage to give  either  reports with  and  [1,3]  2 1 c . T h e s e  11,3]  photolysis  product  Shifts.  A  21a  typical  carbonyl  compounds.  20a w h i c h  competition  and  radical carbonyls  then  with  o f compound 21  /9,7-unsaturated  t h e S;j^(n-7r*) o r T 2 ( n - 7 r * )  Photochemical  in  [1,3]  processes.  leads to b i r a d i c a l 20b  analyzed  photochemical  of biradical  product  21b F i g u r e 0.16  with  /3,7-unsaturated  Direct  shift  s h i f t s are frequently  however,  o f compound 20 ( F i g u r e 0.16)  proceeds to give  products,  sigmatropic  a  results  combination rearrange  excited states.  (ref.  48)  (ref.  50)  The  photochemical m u l t i p l i c i t y  singlet, but t r i p l e t triplet  sensitization  compound  ketene  22  of  bicyclic  leads  F i g u r e 0.17  22 ( F i g u r e 0.17) t o g i v e [ 1 , 3 ]  2 2 c . I n  contrast,  i s o m e r 22b r e v e r s i b l y  direct  photolysis  through ketene  22a. T h i s  of ketenes.^^  Photochemical  Turning  to  1976, u n c o v e r e d  This  to  ketone  i n the  2 2 a i s s t a b l e b e l o w -180 °C a n d g i v e s a n i n f r a r e d b a n d a t 2118 cm'^,  characteristic  in  i s predominantly  s t a t e s a r e n o t uncommon. T h i s i s e x e m p l i f i e d  s h i f t p r o d u c t 22d t h r o u g h b i r a d i c a l of  o f these r e a c t i o n s  interesting  proceeded  with  suggested  a  the  [1.3] S h i f t s .  benzosemibullvalene  a photochemical  [1,3] s h i f t  vinylcyclopropane  direct triplet  or  acetone  process,  to  system,  reaction with  vinylcyclopropane  sensitized and  Bender and Wilson^-^  no  photolysis.  conclusion  was  compound  23.  rearrangement The made  authors as  to  w h e t h e r a c o n c e r t e d p r o c e s s was to  this  discovery,  synthesized  dimethyl benzosemibullvalene a  similar  [1,3]  compounds 24 rearrangement necessity to  or  shift 25  25  yielded  electron  labelled  ( F i g u r e 0.18)  reaction.  products. have  i n v o l v e d . Bender e t  no  These  [1,3]  0.18  Some  Sigmatropic  a  follow-up  in  an  attempt  to  D i r e c t or s e n s i t i z e d p h o t o l y s i s of vinylcyclopropane results  withdrawing  Benzosemibullvalene  Shift.  in  benzosemibullvalene  were groups  c l e a v e d 02^-05^, bond i n o r d e r f o r the r e a c t i o n t o  Figure  al.,  to  and  observe either  vinylcyclopropane  rationalized on  24  both  sides  by  the  of  the  occur.  Derivatives  Studied  for  the  VII.  Photochemistry  In  t h e s t u d y o f t h e di-w-methane rearrangement  derivatives, pathways  Scheffer et a l . ^ ^  vary  with  Dibenzobarrelene which  o f Benzobarrelenes  the  initial  benzo-benzo  feasible  phase  of  can  give  systems  o f the four i n i t i a l  products.  have found  bonding  bonding  pathways  Consequently,  the  dibenzosemibullvalene derivatives,  Figure  0.19  Feasible  Initial  dibenzobarrelene  t h a t some o f t h e s e  the  reacting  different  modes i s  of  are four  dibenzobarrelene.  products  followed;  note  omitted  as  possible  Sites  i n  depending that  the  on two  t h e y do n o t g i v e  products  two r e g i o i s o m e r s a n d t h e i r  Bonding  rearrangement  are  a l l  enantiomers.  the Photochemistry of  Dibenzobarrelenes.  The derivatives  focus of  of  the  present  monobenzobarrelene.  investigation  i s  on  disubstituted  Di-7r-methane rearrangements  i n mono-  b e n z o b a r r e l e n e d e r i v a t i v e s a r e much more c o m p l i c a t e d t h a n counterpart; Also  t h e r e a r e now  i n the second bond-breaking  energetic  requirement  monobenzobarrelenes, mono  six feasible  form  may  for  step  in  p o s s i b l e p h o t o p r o d u c t s . The  of  the  dibenzobarrelenes  that factor  branch  initial  bonding  in  second  step  rearrangement,  but that  be  of  formed  products  is  to r e g a i n aromaticity;  to  give  a  another  may  be  by  It  must  different arise  mechanisms.  from  non-di-jr-methane  an  with  result,  the  host  d i v e r s i t y o f p a t h w a y s a v a i l a b l e make t h i s  t h e p r o d u c t s o f F i g u r e 0.20  may  0.20).  i t  more i n t e r e s t i n g a n d more c h a l l e n g i n g t h a n t h e d i b e n z o b a r r e l e n e Some  dibenzo  sites(Figure  i s n o t a l w a y s p r e s e n t . As  the  its  of  study  systems.  structurally equivalent also  be  reactions  considered as  well  as  from secondary p h o t o r e a c t i o n s . The studied first  photochemistry  compared  to  r e p o r t e d the  (Figure  0.21)  monobenzobarrelenes  the dibenzo s e r i e s .  photochemistry  by  Four years l a t e r ,  of  (27)  upon  photoproducts  were  elucidated  experiment  Zimmerman e t a l . , ^ ^  initial  comes f r o m a  direct  irradiation. in  v i n y l - v i n y l bonding singlet-mediated  by an e l e c t r o c y c l i c  ring  K i t a h o n o k i and  Takano^^  unsubstituted  a  i n 1968.  benzobarrelene  a  gives  benzocyclo-  mechanisms  to  deuterium  labelling  di-7r-methane  benzo-vinyl  (26)  i n acetone.  They c o n c l u d e d t h a t t h e  ( F i g u r e 0.21), and  [2+2]  opening.  The  classical  b e n z o s e m i b u l l v a l e n e p r o d u c t i s d e r i v e d from with  little  showed t h a t b e n z o b a r r e l e n e  octatetraene  by  been  i t t o b e n z o s e m i b u l l v a l e n e (28)  photolyzing Friedman^^  of  I n 1963,  has  these  triplet  rearrangement  the c y c l o o c t a t e t r a e n e  cycloaddition  followed  F i g u r e 0.20  P o s s i b l e Pathways i n the P h o t o c h e m i s t r y  Monobenzobarrelenes.  of  2,3-Disubstituted  2Z  not isolated  F i g u r e 0.21  Phototransformations  Congruent w i t h et  a l . ^ ^ reported  Brewer and studied  his  their  Many  of  the  studied  in  of years.  the  career  techniques  this  series.  compounds  the  31  to  photoproducts  his  investigation  of  compound  26  ,  Grovenstein  i n v e s t i g a t i o n o f t h e d i m e t h y l e s t e r d e r i v a t i v e 29,  naphthobarrelenes  and  some  an  Heaney^-'^  dedicated  studies  the  of the Unsubstituted Benzobarrelene (26).  tetrafluoro  and  the at are  32  (Figure  study the  of  Benzobarrelenes and  30,  0.22).  and  Bender  benzobarrelene  University  creative  synthesized  analog  and 31-37  of  ultimately derivatives  Lethbridge,  elegant (Figure  photolyzed  Bender^^  by  in  Canada.  pioneering  0.22) a r e j u s t Bender  through  Figure  0.22  L i s t o f Some S u b s t i t u t e d  Benzobarrelenes P r e v i o u s l y  (ref.  60)  (ref.  62)  (ref.  63)  (ref.  64)  (ref.  65)  (ref.  65)  (ref.  66)  Studied.  The  established  trends  are  that benzocyclooctatetraenes  the  s i n g l e t e x c i t e d s t a t e . The  initial  is  between  and  example,  the  therefore, is  the  the  chromophore  chromophore  initial  of  bonding  intramolecular  the most e a s i l y  benzobarrelene is  c h r o m o p h o r e f o r compound 34  and  is  the  Similarly,  initial  cycloaddition  d i s r u p t e d jr-system.  26  benzo-vinyl.  [2+2]  come f r o m  bonding  benzo-system;  the  is  For  diester vinyl  diester  vinyl-  occur  through  vinyl. Di-7r-methane the  triplet  rearrangements  excited  state  benzocyclooctatetraenes,  to  give  is  triplet  lifetimes  longer  energy  the  two  formation.  Use  of  benzosemibullvalenes.  bonding  The  to  benzobarrelenes  initial  broken double bonds. transfer  of  less  sensitizers  two  allow  7r-systems  stable also  between the  Unlike  provokes  most  for  for  the easily  internal  initial  the  bond  same  initial  bridging. Recall 0.21)  gives  that  initial  chromophore.  With  triplet  sensitization  This  unsymmetrical  stabilization  so  bonding  t h a t the  formed  is  bonding  benzobarrelenes, considered;  the  the side  the  r a d i c a l s formed i s the  the  2-cyano  vinyl-vinyl  cyano group can  on  resonance  derivative the  which that  one  benzo  of  initial  can  provide  is  favoured.  0.22).  to the of  (Figure  the  (Figure  side opposite  stabilize  to  side  side  33  26  The  cyano  group  two  newly  the  radicals. Only  there  to  i s exemplified with  initial  benzobarrelene  v i n y l - v i n y l bonding instead of  d i - T T - m e t h a n e b o n d i n g m u s t a l s o be more  of  is  behavior tested.  a  small  still of  much  number  of  to  understood  be  benzobarrelenes.  d e r i v a t i v e s has  These  with  been s t u d i e d .  respect  proposed trends  I n a d d i t i o n , t h e many s e c o n d a r y p h o t o p r o d u c t s  to  the  have y e t formed  Therefore, solution  t o be have  fully opened  new  areas  of  research  as  One o f h i s l a t e s t  Bender  has r e a l i z e d i n h i s r e c e n t s t u d i e s .  investigations  is  2,3-benzobicyclo[4.2.0]octa-2,4,7-triene of b e n z o c y c l o o c t a t e t r a e n e 38a, which of  a  benzobarrelene  rearrangement  38.  the  derivative  in  Compound  with  turn  39  is  39,^^  a  undergoes  photochemistry a  of  photoproduct  singlet  photoproduct  a triplet  di-;r-methane  t o a f f o r d b e n z o s e m i b u l l v a l e n e 39a.  (ref.  Figure  '  0.23  Photochemistry  of  68)  l-Cyano-2,3-benzobicyclo[4.2.O]octa-  2,4,7-triene (39).  VIII.  Object of Research  In and  this  disubstituted  i r r a d i a t e d to assist  benzobarrelene the  thesis,  first  crystalline For  in  a  better  photochemistry  reports^^  of  phase as w e l l clarity,  the  and,  benzobarrelenes understanding more  monobenzobarrelene  of  are  synthesized  solution  interestingly, photochemistry  to  phase provide  in  the  i s divided  into  a s i n p o l y m e r medium. Results  and  Discussion section  seven p a r t s .  The  Part  this  I  of  benzobarrelene naphthalene done p r i o r One  p r e p a r a t i o n of the thesis.  ring  to  an  system  is  stems  feature  magnetic  extremely  Part  bullvalene  r e g i o i s o m e r s from  of  I I I of this  He  reported  of t h i s the  direct photolysis from  acetone  to determine become  this  F i g u r e 0.24  the  addition  di-7r-methane  this  as  the  (NMR)  four  distinctive thesis  and  a 5  : 3  the n a t u r e with  Symmetrical  of : 2 In  of these this  of  a  can  be  on  chemical  details  study  is  ( F i g u r e 0.20).  these  photoproducts  the  disubstituted  shifts  the assignment  and  coupling  of benzosemi-  spectroscopic techniques.  compound was  formation  of  protons  thesis deals i n i t i a l l y  sensitization.  familiar  i n the s y n t h e s i s o f  Diels-Alder  with  l,4-ethenonaphthalene-2,3-dicarboxylate photochemistry  in  Substituent alterations  spectroscopy  skeleton possess  patterns.  Part  a  described  are d i s u b s t i t u t e d benzosemibullvalenes  resonance  II  step  is  addition.  associated  informative,  semibullvalene  from  derivative.  or subsequent to t h i s unique  materials  fundamental  acetylene  t h a t a l l the products Nuclear  The  starting  with  (29,  dimethyl Figure  1,4-dihydro0.24).  i n v e s t i g a t e d by G r o v e n s t e i n  a  in  The 1969.^^  benzocyclooctatetraene derivative ratio this  of  study,  three t r i p l e t  system  Disubstituted  three  and  unidentified  i t was  considered  photoproducts  to proceed  Benzobarrelenes  into  in  the  Studied.  upon  products essential order  solid  to  phase.  Several also  other  investigated  in  substituent patterns shown  in  Figure  symmetrical Part  0.24.  investigated,  others,  efficiently  Favorable  intersystem  unsymmetrical  are  ascertain  related  the  benzoyl  crosses  to  give  The  42, only  benzobarrelenes to  reorganize  selectivity.  i n going  dibenzoyl  the  Figure  Upon n o t i n g  studied  in  derivative  affect  an  the  crystal  0.25  symmetrical unlike  triplet  Part  42.  IV  The  ideal  the  products  This  state,  selectivity  the  series  media.  Unsymmetrical Benzobarrelenes  Studied.  of  this  observation  system.  solution  packing.  the s t r i k i n g  from s o l u t i o n to the s o l i d  i n polymer matrix  are  state.  h o p e f u l l y demonstrate the e f f e c t s of v a r y i n g the c r y s t a l state  substrates  groups i s r e p l a c e d w i t h an e s t e r , t h e a l k o x y  dramatically  are  effects of different  benzobarrelene  e s t e r c a n e a s i l y be a l t e r e d t o l i t t l e but  the  to the i n t e n t i o n s , the l a s t  o f i t s e a s e i n i n t e r s y s t e m c r o s s i n g makes t h i s of  benzobarrelenes  photochemistry.  2,3-dibenzoyl  i n s o l u t i o n and the s o l i d  thesis  I I I to  on b e n z o b a r r e l e n e  system  The  disubstituted  If  one  group o f t h e photochemistry  in  turn  lattice  on  will solid  d i f f e r e n c e s found was  also  studied  Varying the  crystal  Part  V  should  packing,  t h e same  not  Different  be  which  40  were  solid  state. the  different are  the  and  use  state  ratios  of  is  salts  to  In  theory,  desired  in  alter  crystal  this  study.  packing f o r  the counterion.  of  salts  in  of  and  photolyzed  the  different  reactions  an  can  be  products attempt  the  changes  s i g n i f i c a n t l y by s i m p l y a l t e r i n g  benzobarrelene both  in  crystal  environments  measured In  to deliberately  Acid.  from  addition,  the some  affect intersystem  photoproducts.  S a l t s of Benzobarrelene D i c a r b o x y l i c  dicarboxylic  s o l u t i o n and i n t h e  lattice  directly formed.  c r o s s i n g t o enhance t h e f o r m a t i o n o f t r i p l e t  F i g u r e 0.26  undoubtedly  photochemistry  triplet  synthesized  molecule  solution  synthesized  solid  a  of  inorganic  The e f f e c t s  on  i s what  molecule.  affected  organic  acid  salts  substituents  demonstrates  essentially  on  the  The Scheffer's (Figure  discovery  group w i t h the 0.27)  rearrangement is  inspired  a r e a c t i o n which  unusual  study an  2,3-dicarboxylate  of  tri-TT-me thane'"  9,10-dimethyl  investigation systems.  understandably  In P a r t VI, the  dimethyl  F i g u r e 0.27  an  to other barrelene  saturated carbon. 46,  of  involves  of A  rearrangement  dibenzobarrelene  the  generality  tri-TT-methane  of  in 46^-'this  rearrangement  t h r e e jr-systems s e p a r a t e d by  monobenzobarrelene  analog  of  a  compound  1,4-dihydro-l,4,5,8-tetramethyl-1,4-ethenonaphthalene( 4 7 ) , was  Bridgehead  s y n t h e s i z e d and  irradiated.  Methylated Barrelene Dimethyl  Esters.  Cumulatively, benzosemibullvalene photochemical far  Part  this  photoproducts  [1,3] s h i f t s .  f r o m uncommon,  system.  through  few  have  VII briefly  i t was n o t i c e d t h a t many o f t h e  efficiently  Although  reported  assesses  these  i n which  underwent  photochemical  been  with the photostationary states exist.  study  i n  the  [1,3] s h i f t s  are  are  benzosemibullvalene  [1,3] s h i f t s  they  secondary  found  i nconjunction to  frequently  RESULTS AND  DISCUSSION  PART I .  PREPARATION OF STARTING MATERIALS  The formal  basic  structure  nomenclature  numbering  is  shown  from the naphthalene commonly  as  w i l l be used  of  of  the  starting  r i n g system,  however, Throughout  the the  and  the  skeleton  is  known  more  thesis,  the  two  names  interchangeably. the  method  of  Grovenstein  of  dimethyl  [4+2] c y c l o a d d i t i o n r e a c t i o n ( D i e l s - A l d e r  Figure  1.01  Synthesis  of  et  Benzobarrelene  al.,^^  (29)  acetylenedicarboxylate  thermal  React ion.  the  i n Figure 1.01. The o r i g i n o f t h i s nomenclature stems  dihydro-1,4-ethenonaphthalene-2,3-dicarboxylate addition  possess  "1,4-dihydro-1,4-ethenonaphthalene,"  "benzobarrelene".  Following  the  materials  to  was  dimethyl  1,4-  prepared  naphthalene  by  in a  reaction).  Diester  29 f r o m a D i e l s - A l d e r  I t has dienes  for  been w e l l  recognized  Diels-Alder  addition.  r e q u i r e s h e a t i n g i n a s e a l e d tube 25%  is  considered  s t u d i e d here of  to  be  were p r e p a r e d  that The  naphthalenic  are  poor  p r e p a r a t i o n o f compound 29  above  f o r 72 h o u r s ,  good.  In  through  light  and  systems  the r e p o r t e d  of t h i s ,  many  achieved through from  this,  the s a p o n i f i c a t i o n  of diester  29  i n a 24 h o u r d e h y d r a t i o n o f d i a c i d 40  All  compounds  three  (29,  40,  and  41)  p u r i f i e d by  recrystallization.  Figure  D e r i v a t i z a t i o n of Benzobarrelene  1.02  29.  acid  are  using solids  Dimethyl  Ester  41  chloride.  c a n be  29.  is  Extending  anhydride  oxalyl and  Synthesis (40)  ( F i g u r e 1.02).  1,4-dihydro-l,4-ethenonaphthalene-2,3-dicarboxylic  is prepared  of  benzobarrelenes  d e r i v a t i z a t i o n of diester  1,4-dihydro-l,4-ethenonaphthalene-2,3-dicarboxylic  yield  easily  The p a r t i a l l y were in  also a  prepared.  Grignard in  was u s e d  in  place  Figures  1.01  distributed  over  ring.  NMR  The  benzobarrelene C^^  and  C4  The  a  gave  ca. of  95%  spectra 29  are  positions  isotopic  1.02.  1,4,5, of  a  these bromo  purity.  in As  and  8  the a  the  in C5  The  starting  materials  group w i t h  deuterium  positions  Figure and  C3  and  from  routes  deuterium  of  1-bromo-  1-deuterionaphthalene  synthetic  result,  non-deuterated  provided and  of  of  1-deuterionaphthalene^^  naphthalene  and the  versions  replacement  reaction  naphthalene,  in  deuterated  the  positions  is  evenly  benzobarrelene  selectively  1.03.  described  Notice  deuterated that  the  are magnetically  e q u i v a l e n t owing t o t h e p l a n e o f symmetry p r e s e n t i n t h e m o l e c u l e .  u 'J""""'J  7 ^  'I  3  ppm  1/4D  1/4D CO2CH3 COoCH,  1MD  ppm Figure  1.03  NMR  Benzobarrelene  Spectra of  29-D  in  CDCI3.  Benzobarrelene  29  and  Partially  Deuterated  Synthesis ( 4 2 ) was  of  accomplished  acetylene  (57)  a  19%  was  yield  from  added  a  in  tube  (180  42  from  after the  fumaryl  Friedel-Crafts  trichloride,  to  The  of ene-dione  vinyl  good and  yields  of  finally,  dibromide  Figure (42).  group  1.04  the  naphthalene  of  synthesized  Stemming  through  with  heating i n a sealed  2,3-dibenzoyl-1,4-dihydro-1,4-ethenonaphthalene  give  meso  Diels-Alder (Figure  °C),  the  1.04).  chromatography. procedure  chloride,  of  two  reaction,  was  1  dibenzoyl1/2  depleted  hours  give  Dibenzoylacetylene  (57)  R.E.  Lutz  catalyzed  by  in  of  1951.  benzene  anhydrous  is  then  reacted  with  bromine  to  2,3-dibromo-l,4-diphenylbutane-l,4-dione (57)  is  prepared  i n an e l i m i n a t i o n  are  aluminum  trans-1,4-diphenyl-2-butene-l,4-dione 55  of  to  equivalents  the a d d i t i o n o f t r i e t h y l a m i n e  Preparation of  of  After  alkyne  1,4-diphenyl-2-butyne-1,4-dione  56 b y  reaction  (55). give (56), from  reaction.  2,3-Dibenzoyl-1,4-dihydro-l,4-ethenonaphthalene  The -"-H are  shown  in  NMR  spectra  Figure  c a r r i e s a unique s e t resonate this vinyl  between  neighbor  1.05. of  5-6  multiplicity  along  they  constants. easily  In  can  ppm  benzobarrelenes  Interestingly, The  with from  with  a  a a  the  the  strong  weaker  by  NMR  compounds shown i n F i g u r e 1.03.  two  (C^^  and  C4)  and  41  skeleton protons  doublet of doublets coupling pattern;  distinguished  addition,  40  benzobarrelene  bridgehead  (2  (5  from  groups  integration  Hz)  coupling  to  i t s  Hz) f o u r bond d i s t a n t c o u p l i n g  The v i n y l p r o t o n s r e s o n a t e  be  differentiated  symmetrical  signals.  comes  to the opposite v i n y l . however,  of  i n the  aromatic  region;  the aromatics by the c o u p l i n g of of  aromatic the  protons  deuterium  are  labelled  F i g u r e 1.05 and  41  H NMR  (CDCI3).  Spectra of  Symmetrical  Benzobarrelenes  40  (DHSO-dg)  The 43  was  synthesis  achieved  benzobarrelene opened by  of unsymmetrical benzoyl methyl ester  through  further  anhydride  reaction with  41  manipulation  (Figure  dry methanol,  and  ethenonaphthalene-2 , 3 - d i c a r b o x y l i c acid  ester  was  59;  this  ester  acylation desired  reacted was  with  acid  oxalyl  by  benzobarrelene  anhydrous 43.  The  to  esters  respectively).  and  45,  give  the  Selectively prepared. through  This the  benzoyl  deuterated  was  done  described  methyl  i n the  this  is  with  mixture a 0.25  43  taking  C]^, C 4 ,  represented  deuteration  on  the  C4,  give  was  (58).  acyl  methyl the  to be  ethyl  studies.  This  chloride  (Figure  and  ester  C 5 , and  Cg  a  positions  also  anhydride  The  For  highly  was  41  resulting  mixture  positions. as  are  43  1.06).  the  isopropyl  esters  monodeuterated C3  yield  easily altered  1,4,5,8 - l a b e l l e d  diagrammatically C^^,  ester  can  state  and  ring  1,4-dihydro-l,4-  trichloride  benzoyl  a  C5,  to  These  route  was  gave  side-chain  benzoyl  synthetic  ester  deuterium placed  by  anhydride  corresponding  c r y s t a l l i n e m a k i n g them i d e a l f o r s o l i d  symmetrical  w i t h benzene i n a F r i e d e l - C r a f t s  aluminum  under a c i d i c c o n d i t i o n s  the  monomethyl  chloride  ester  The  work-up  immediately reacted  catalyzed  (44  1.06).  of  benzobarrelene  with  the  simplicity,  single (43-D).  molecule  Je  MeOH  a)  41  o  52  O OCH3  OH  O  Oxalyl Chloride CH2CI2  O -OCH. Cl  MCI. Benzene  43 O  53  O  EtOH A , H+  M  7~Ph  O  b)  Figure  1.06  a) P r e p a r a t i o n  of Benzoyl Esters  4 3 , 4 4 , a n d 45.  b) Monodeuterated B e n z o y l M e t h y l E s t e r  The NMR a  unique  pattern  The b r i d g e h e a d as  two  symmetry,  spectra of  of  unsymmetrical  benzobarrelenes  signals associated with  the s k e l e t o n  (Cj^ a n d C 4 ) p r o t o n s a r e no l o n g e r  adjacent  doublet  the aromatic  and  of doublets vinyl  m u l t i p l e t b e t w e e n 6.9-7.6 ppm  equivalent  b e t w e e n 5-6  proton  (43-D).  signals  and a r e t h e r e f o r e  less  ppm.  Due  overlap  also (Figure and  contain 1.07). resonate  to the lack of as  informative.  a  complex  Figure  1.07  NMR  Spectra  of Benzoyl  E s t e r s 43  and  45  i n CDCl  The  amine  dicarboxylic  acid  stoichiometric s o l u t i o n was  and  salt  of  1,4-dihydro-l,4-ethenonaphthalene-2,3-  prepared  an  forms  by  dissolving  a  for  approximately  precipitate  which  double  salts,  a  slight  inorganic  salts,  a  stoichiometric  in  water  was  Crystals  of  the  derived  The  salts  prepared,  by  analytical  the  acid  with  amine i n e t h y l a c e t a t e o r a c e t o n i t r i l e .  reflux  hydroxide  and  of  were  s t i r r e d under  amine for  (40)  amount  corresponding With  salts  added  to  salts  shown  as  the  amine of  diacid from  and  filtered.  was  used,  acetonitrile.  suitable were  solvents.  characterized  IR,  MS-DCI,  C-H  analysis,  substrate  investigated  in  the  thesis,  dimethyl  dihydro-1,4,5,8-tetramethyl-l,4-ethenonaphthalene-2,3-dicarboxylate prepared  from  dicarboxylate (Figure  1.08).  to  reaction presence  DMAD  64  used  the  Diels-Alder  (DMAD)  derivative was  the  mp. The n e x t  was  The  t h e c a t i o n as a  in  0.26,  NMR,  hour  be e a s i l y  amount  grown  Figure  such  can  of  the  were  in  techniques  excess  one  a  is  to is  not.  synthesize  of of  The  method  compound  devised  64.  The  p-xylene aluminum  with  is  naphthalone  ring (61).  The  methyllithium, 1-naphthol  (62)  with  closure  to  carbonyl giving  in  88%  acetylene-  yield.  group  of  W.L.  (64)  naphthalene  Mosby^^  step  The  acid  pyrophosphoric give  but,  i n 1952  involves  7-valerolactone  trichloride.  Compound 60  treated  by first  4-(2,5-dimethylphenyl)-pentanoic  dehydration  dimethyl  available,  resulting  then  of  (47)  1,4,5,8-tetramethylnaphthalene  commercially  anhydrous anhydrous  addition  1,4-  yield (60)  acid  the  in  the  of  the  was  90%.  facilitating  a  2,3-dihydro-4,5,8-trimethyl-1ketone  61  was  reacted  with  1,2,3,4-tetrahydro-1,4,5,8-tetramethylThis  crude  naphthol  is  then  stirred  at  room  temperature  in  acidified  1,2-dihydro-1,2,5,8-tetramethylnaphthalene reaction. formed  Finally, from  compound other  63.  a  catalyzed  The  synthetic  the  yield routes  reported.However, m e t h o d o f Mosby was  Figure  1.08  in to due  tetrahydrofuran (63)  in  (THF) a  this  temperature last  naphthalene to  simple  (64)  dehydrogenation  s t e p i s 17%. S i n c e 1952, derivative availability  64 of  is of  several  have  been  reagents,  the  used.  Synthesis of Tetramethyl Benzobarrelene  give  dehydration  1,4,5,8-tetramethylnaphthalene high  to  Dimethyl Ester  47.  PART  II.  CHARACTERIZATION  OF  DISUBSTITUTED  BENZOSEMIBULLVALENE  PHOTOPRODUCTS  Most  of  the  photoproducts  benzosemibullvalenes, either alternative reaction  mechanisms.  mechanisms,  a  respect to the structural  from  2 . 0 1 . The  pentalene  embarking  strong  foundation  assignment  proper  structure.  t h e di-7r-methane  Before  Benzosemibullvalene Figure  synthesized  the  Chemical  carbon-carbon  of  name  for  bonds  "benzo[a]"  cyclopropyl  denotes  number i n d i c a t i n g The  by  relatively  signals downfield  usually of  7  ppm.  with  to  depicted  i s taken a  from  i n the  numbering system t o  to represent the different  The p r o p e r  on  the c  Chemical A b s t r a c t s  describes  the pentalene at  and d  the bonds  descriptions  magnetic  The  NMR  occur  a  bond,  and the  are involved are  the  s k e l e t o n . The  preceded  upfield As  a  proton  result,  3  infrared  resonances 3.0  spectrum, of  a r e most  resonance,  between  i n t h e NMR  appear  name  benzosemibullvalenes  nuclear  skeleton clear  established  i n a by  a  l o c a t i o n on t h e b e n z o s e m i b u l l v a l e n e s k e l e t o n .  spectrometry.  semibullvalene is  their  from  o f elaborate  skeleton  system  group  Substituent  disubstituted  characterized  benzo  that  ring.^*^  be  "2a,2b,6b,6c-tetrahydro"  a  or  2a,2b,6b,6c-tetrahydrobenzo[a]cyclo-  t h e hydrogens  indicates  "cyclopropa[cd]"  mass  of  basic  system.  i s  The  p o s i t i o n a n d number  and  the ring  benzosemibullvalene  propa[cd]pentalene.  discussions  i n addition  has an a l p h a b e t i c a l  are  photoproducts.  Abstracts  describe the carbons,  thesis  rearrangement  must  o f these  has  Pentalene,  on  i n this  as ppm  a n d 6.5  informatively spectroscopy,  on  the  benzo-  ppm;  This  region  the saturated  hydrocarbon  and aromatic protons  semibullvalene  peaks  are  appear easily  distinguished Where  and  possible,  taken.  X-ray  seldom  suffer  melting  analyses  from  points  were  overlap  and  performed  elemental only  s t r u c t u r e s c o u l d n o t b e f i r m l y a s s i g n e d f r o m NMR  in  other  signals.  analyses  situations  were  where  the  techniques.  Pentalene  F i g u r e 2.01  with  Benzosemibullvalene  a) S t r u c t u r e o f P e n t a l e n e . b) S t r u c t u r e o f B e n z o s e m i b u l l v a l e n e  o r 2a,2b,6b,6c-Tetrahydro-  benzo[a]cyclopropa t cd]pentalene.  A.  Characterization of  2a,6c-Disubstituted-2b,6b-dihydrobenzo[a]cyclo-  propa [cd]pentalene.  The p r o t o n bullvalenes  are  NMR  spectra  shown  in  of  some  2a,6c-disubstituted  F i g u r e s 2.02 a n d 2.03. The s k e l e t a l p r o t o n s o f  the 2 a , 6 c - d i s u b s t i t u t e d b e n z o s e m i b u l l v a l e n e s chemical  signal  a l l have s i m i l a r  s h i f t p a t t e r n s . The m o s t s h i e l d e d a r e  a s i n g l e t and a doublet comes  from  (J = 3 Hz), respectively.  the  C2  vinyl  coupling  doublets  The  next  p r o t o n as a d o u b l e t  ( J = 5,3 H z ) . The f o u r a r o m a t i c p r o t o n s  m u l t i p l e t a b o v e 7 ppm.  The  chemical  shifts  and  a n d Hg},, g i v i n g r i s e t o most  from  shielded  ( J = 5 H z ) , and the  m o s t d e s h i e l d e d p r o t o n o n t h e s e m i b u l l v a l e n e s k e l e t o n i s o n C]^, of  benzosemi-  resonate compound  v a r y s l i g h t l y b u t the p a t t e r n and c o u p l i n g c o n s t a n t s remain  a  doublet  as a complex to  compound  similar.  H  PPM Figure  2.03  bullvalenes  H,  6b  •.4 Proton  29a  '2b  NMR  i n C D C I 3 and  Expansions 40a  of  i n DMSO-dg.  2a,6c-Disubstituted  4.1  ppm  Benzosemi-  B.  Characterization  1,6c-Disubstituted-2b,6b(2aH)-dihydrobenzo[a]-  of  cyclopropa[cd]pentalenes.  The bullvalenes  NMR  spectral  are  shown  2a,6c-disubstituted resonate  3.0  proton  8,3  Hz).  p r o t o n o f Cg|3 proton benzo  doublet  as  the 6.5  some  2.04.  1,6c-disubstituted Parallel  protons  on  shielded  the  The  semibullvalene  the  Q^a.  systems Photon  N e x t i s t h e C2b p r o t o n d o u b l e t a (J  group r e s o n a t e  singlet. =  3  Hz)  semibullvalene  c l e a r of the aromatic  is  Considerably  as a c o m p l e x m u l t i p l e t a b o v e  7  and s a t u r a t e d pattern  is  also  ( J = 8 Hz)  The  ring  NMR  doublet  downfield  a t a b o u t 6 ppm.  benzosemi-  to the s i t u a t i o n of the  ppm,  benzosemibullvalene  c h a r a c t e r i s t i c . Most =  and  for  Figure  resonances.  1,6c-disubstituted  (J  in  analogs,  between  hydrocarbon  data  very doublets  f o l l o w e d by the C2  vinyl  aromatic protons  o f the  ppm.  is  of  of  the  F i g u r e 2.04 bullvalenes  NMR 29b  Spectral  a n d 43c  Expansions  i n CDClo.  of  1,6c-Disubstituted  Benzosemi-  c.  Characterization  of  1,2-Disubstituted-2a,2b,6b,6c-tetrahydrobenzo-  [a]cyclopropa[cd]pentalenes.  NMR of  this  spectral The  spectroscopy set  consistently doublet  of  neighbors  =  doublets (J  =  further doublet  6  unique.  The  as  as  signal  a  a  However,  slightly  the  triplet.  triplet  of  the  downfield  from  the  two  ==  identical of  €2^.  a l s o has  triplets.  are  6  Hz);  coupling  the  a  NMR  ppm.  is  each  is a  of i t s  result,  the  o f the 02^ proton to  i t s of  the  neighbors  doublet o f  coupling  resulting  Finally,  a t a b o u t 4.3  to  doublet same  skeleton  signal  as  of doublets  The  the  benzosemibullvalenes.  strength  i t s neighbors,  ( J = 6 Hz) i s most d e s h i e l d e d ,  2.05  semibullvalene  coupling (J  characterization  proton  The d o u b l e t  from  of  this  same  downfield  a l l three  the  Figure  shielded  f r o m t h e Cg^, p r o t o n to  in  in  1,2-disubstituted  most  is  essential Shown  pattern  doublets.  Hz),  Hz)  some  coupling  appears  6  of  (C2b a n d Cg^,)  a l s o appears (J  photoproducts.  expansions  proton  signal  of  p r o v e d t o be  strength  i n a quartet Cg^,  proton  2b  2a  CO,H  6b  COjH  H  5.5  5. 0  —I—^—  4. 5  2a  —I—  4. 0 pprt  3.5  COPh  5. 0  43d  •CO2CH3  COPh  43e  43e  43d  43d  43d+43e  43d 43d  43e  43e 43e  J  U I '  '  I I  4.  Figure  2.05  bullvalenes  I  I T  2  NMR  I I  4.  I • . 0  Spectral  i. 8  Expansions  40b a n d a m i x t u r e o f 43d a n d  ' ' I ' ' ' ' I 3. 6  of 43e.  I 34  ' ' I ' 3.2  1,2-Dlsubstituted  I  I I I I  i  I  I PPM  I ' I I  0  Benzosemi-  I I  The are the  1,2-disubstituted  inseparable proton  proton  NMR  from  those  clearly  benzosemibullvalene to  in  intensities,  compounds  respect  column  i s shown  signal  distinguished two  by  the  benzosemibullvalenes  43d  chromatography,  an  Figure  the  indicate  of  that  The  they  of  compound signal  expansion  of  single  can  be e a s i l y  patterns  of the  1,2-disubstituted  ambiguity  the methyl  43e  relative  are both  However,  positions  From  one  other.  derivatives.  relative  2.05.  t h e peaks of  and  and  arises  with  e s t e r and the benzoyl  groups.  E = methoxyl B = phenyl  2a  B(E)  -9  2.08 ppm  8.40 ppm  o o pm 5.95 ppm  E(B)  H  OCH3  substituted region of benzosemibullvalene  F i g u r e 2.06  was  noticed  assignment that  the  benzosemibullvalenes  S5a  than  the  was  deshielding strength  based  chemical  were  other.  on  shifts  distinctly the  Therefore,  between  r  OCH3  65b  and the Methyl  Compounds 6 5 a a n d 6 5 b .  s t r o n g e r d e s h i e l d i n g e f f e c t on Hg^j)  1.98 ppm  Relative Deshielding Capacities o f the Benzoyl  E s t e r Groups Determined from  The  CH3  I  the  NMR of  benzoyl  and  different.  neighboring the  chemical  Hg^^ One  methine  determination and  the  shift on  data. the  group proton  It two  has  a  (H2a o r  of  the  relative  ester  will  provide  the  answer.  A  uncovered  from  compounds  is  bullvalenes. group  has  on  set  a literature very  of  similar  stronger is  65b.  compounds  s e a r c h t h e to  The r e p o r t e d NMR  b e n z o y l o n 65a ester  model  the  a n d 65b,  magnetic  ppm  properties;  result,  of  these  s u b s t i t u t e d r e g i o n o f the benzosemi-  downfield  B a s e d on t h i s  F i g u r e 2.06) was  environment  o f t h e s e compounds r e v e a l  deshielding  0.10  (65a  of  the  the  that  methyl  methyl  the  benzoyl  adjacent to the  adjacent  to  the  t h e s t r u c t u r e s compounds 4 3 d a n d 43e  w e r e a s s i g n e d a s shown i n F i g u r e 2.05. Another disubstituted  interesting  benzosemibullvalenes  C2]-, p r o t o n s . R e c a l l have  similar  that both  similar  study  reagent  C2a  and  orientations.  Figure  2.07  Eu(hfc)3.  the  the  characterization  assignment  give r i s e  chemical  of  of  1,2-  the  arid  t o one p r o t o n t r i p l e t s  shifts.  This problem  (Eu(hfc)3).  It  was  and  i s s o l v e d by  reasoned  from  w i t h c y c l o o c t a t e t r a e n e d e r i v a t i v e s ^ - ^ t h a t the benzosemi-  b u l l v a l e n e would complex to the s h i f t The  with is  signals  but not i d e n t i c a l  the use o f a l a n t h a n i d e s h i f t a  problem  protons  are  of  as  shown  in  Figure  v e r y c l o s e t o each o t h e r and have  Since the €23 proton  Complexation  reagent  i s nearer  to the s i t e  1,2-Disubstituted  of  2.07. similar  complexation.  Benzosemibullvalenes  to  it  s h o u l d be more  successive changes chemical 43e,  sensitive  additions  in  chemical  shift  i n Figure  F i g u r e 2.08  of  to  the s h i f t  shifts  changes  additions  of  (Au)  reagent  each  are  of  the  shift  reagent.  From  t o a maximum o f 30 m o l e %, t h e  signal  plotted  for  were  recorded.  These  both  compounds,  43d and  2.08.  P l o t s o f Change  i n Chemical  Shift  o f E u ( h f c ) 3 A d d e d f o r Compounds 43d a n d 4 3 e .  (Au)  Against  the  Mole  %  The  slopes  in sensitivity the  more  ii2h-  '^^^  D.  in  between the  graphs  This  to  this  the  o f F i g u r e 2.08  reagent.  triplet  confidence  Consequently,  the  to the s h i f t  sensitive  correlation  these  on  allows  and  assignment  other  slopes  sensitive  supported  by  triplet  the  of to  positive  to t h e i r e s t a b l i s h e d assignments.  NMR  spectrum  Disubstituted  the  H2b  signals  in  and  expansion  Benzosemibullvalenes.  of methyl  b e n z o [a] c y c l o p r o p a [ c d ] p e n t a l e n e - 6 b - c a r b o x y l a t e Figure  2.09.  The  semibullvalene following  43f  semibullvalene also  has  skeleton  an  most  c l o s e l y by  shielded  followed  of a  B.-^  doublet  These assignments  Although,  the  (J  =  whether  or reversed molecule,  pattern  the  still an  X-ray  position remained. analysis  5  Hz) . The  doublet  of  signals.  shown i n F i g u r e  2.10.  =  of  8,3  from  by NMR  Hz)  (J = 8 Hz). (J  =  in  The  to  skeleton,  Hz)  resonate  decoupling led  was  to  the  performed an  ORTEP^^  crystalline by  Dr.  diagram  the  and above  experiments. the  the  assignment uncertainty  the s u b s t i t u e n t s are c o r r e c t l y  Owing  is  Resonating  5,3  aromatic protons  supported  evidence  the p o s i t i o n o f the s u b s t i t u e n t s ;  (J  doublet of doublets  were a l s o  spectroscopic  t h e H2b  6b,6c-disubstituted benzosemibullvalene to  shown  o f 6 b , 6 c - d i s u b s t i t u t e d benzo-  doublet of doublets  f u r t h e r d o w n f i e l d i s t h e v i n y l H2  7 ppm.  are  s i g n a l s a r e d e s c r i b e d g o i n g from most s h i e l d e d t o l e a s t s h i e l d e d H2a  vinyl  6c-benzoyl-2a,2b-dihydro(43f)  informative  i n p r o g r e s s i v e o r d e r . The  is  assignment  1,2-disubstituted benzosemibullvalenes.  The  as  the  less  s i g n a l s a r e more s h i e l d e d t h a n  C h a r a c t e r i z a t i o n of Other  the  for  the is  show l a r g e d i f f e r e n c e s  nature  assigned of  the  P o k k u l u r i to confirm of  the  structure  F i g u r e 2.09  NMR  Spectrum  and E x p a n s i o n o f M e t h y l  benzo[a]cyclopropa[cd]pentalene-6b-carboxylate  6c-Benzoyl-2a,2b-dihyd  (43f) i n  CDClo.  F i g u r e 2.10  Stereodlagram  of Methyl  propa[cd]pentalene-6b-carboxylate  The  NMR  spectrum  in  6c-Benzoyl-2a,2b-dihydrobenzo[a]cyclo-  ( 4 3 f ) from X-ray  Figure  2.11  Analysis.  i s that o f methyl  2a,6b-dihydrobenzo[a]cyclopropa[cd]pentalene-2b-carboxylate semibullvalene  ring  system  a p p e a r i n g as a d o u b l e t The a  other doublet  the  doublet  aromatics [1,3]  signals  are  of  doublets  (J  doublets  resonate  photochemical  systems, and the f a c t 43f,  the  ( J - 3 Hz) ; n e x t  two  of  relative  ^2a  shows  7  shifts  X-ray  5,3 =  downfield.  The  Hz)  Through  present  is  f r o m t h e Ci an  (43g) i s  -  proton  signal 2  on  Hz) . C2  is  upfield  of  understanding  a  The  proton. Again, the of  the  benzosemibullvalene  product  the e s t e r and the b e n z o y l  analysis.  (J  slightly  i n many o f t h e s e  compound of  doublet  This  (43g). shielded  i s t h e Hg^,  Hz);  5,2  ppm.  this  positions  assigned without another  =  (J  above  that  further  most  6c-benzoyl-  of  compound  g r o u p s c a n be  '  M  I I I I  I  I I I I I '•  5,8  I I  I  I  I I I I I I  I 1.1  5.6  I I ' I I I I I I I ' • ' ' I • ' ' ' I 50  5.3  I I ' I  *B  —~i  1  - 1  r  •  -îB  -  ^  ppm Figure  2.11  a ) NMR  S p e c t r a l Expansion of Methyl  6c-Benzoyl-2a,6b-dihydro-  benzo[a]cyclopropa[cd]pentalene-2b-carboxylate CDCI3.  b ) D e c o u p l i n g a t 4.52  ppm.  (43g)  in  From e x a m i n a t i o n spectra  in  this  of  the  section,  many  the  disubstituted  substituent  benzosemibullvalene  locations  characteristic patterns of signals  i n a clear region o f the  Although  be  the  substituents  s i g n a l s and  their  coupling  provides  vital  asset  a  may  different,  constants  in  the  stay  the  give NMR  NMR c a n b e u s e d t o d e d u c e t h e s t r u c t u r e o f t h e p h o t o p r o d u c t s As  an  extension,  determining photoproduct  ratios.  s e m i b u l l v a l e n e compounds therefore,  analysis  with  s i g n a l s . •'-'^^ the  rarely  i t i s possible  Quantitative accurate  NMR  inherent  by  projected  This  aspect  instability  to the h i g h temperature  i s used  i n many  The s i n g l e p r o t o n suffer  from  to obtain a clear  NMR  has  been  well  these  signals  This  systems, as  easily.  studies  overlap  of  unchanged.  study o f the benzobarrelene  to  spectrum.  location  relatively  rise  for  directly  o f the d i f f e r e n t  with  each  other;  integration of the signals. established  to  be  very  i n t e g r a t i o n e r r o r s o f + 3% o n b a s e l i n e - s e p a r a t e d proved  to  that  many  GC c o l u m n s .  be of  quite  effective  because  these benzosemibullvalenes  of have  PART I I I .  A.  PHOTOCHEMISTRY  Photochemistry  OF SYMMETRICALLY DISUBSTITUTED  of  Dimethyl  BENZOBARRELENES  1,4-Dihydro-l,4-ethenonaphthalene-2,3-  dicarboxylate (29).  The  solution  photochemistry  of  the  title  1,4-dihydro-l,4-ethenonaphthalene-2,3-dicarboxylate investigated ago. gives  They  by  Grovenstein,  discovered  complete  that  conversion  Campbell,  direct of  octatetraene-7,8-dicarboxylate  and  (29),  Shibata^*^  photolysis  starting  compound,  material  of  dimethyl  was over  first 20  years  benzobarrelene  29  to dimethyl benzocyclo-  (29c) and t h a t a c e t o n e - s e n s i t i z e d p h o t o l y s i s  gives three u n i d e n t i f i e d products  i n a 5 : 3 : 2 ratio.  Three Products 5 : 3 : 2  Figure  3.01  Photochemistry  o f Compound 29 R e p o r t e d  by G r o v e n s t e i n e t a l .  i n 1969.  I n 1975, order  to  Bender  determine  Shown i n F i g u r e  3.02  and  the are  Brooks^^  mechanism two  of  possible  reinvestigated  this  cyclooctatetraene routes,  both  compound  in  29c f o r m a t i o n .  initiate  from  a  photochemical  [2+2]  r i n g opening.  However,  bonds  involved.  benzobarrelene Photolysis  29c w i t h l a b e l s the  initial  the  routes  Starting  from  29 w i t h  of  intramolecular  this solely  deuterium  cycloaddition differ  with  vinyl-vinyl  the  labels  C2  bridging  respect  at  the  and  Cg  route.  Cy  the  they  and  Cg  double  prepared positions.  gave b e n z o c y c l o o c t a t e t r a e n e  positions, No  by a thermal  to  2-deuterionaphthalene,  deuterated benzobarrelene at  followed  mention  corresponding was  made  to  o f the  acetone-sensitized photoreaction.  not observed  F i g u r e 3.02 Performed  M e c h a n i s t i c Study  f o r Benzocyclooctatetraene  b y B e n d e r a n d Brooks®^ i n 1 9 7 5 .  29c  Formation  In  order  to  extend  s o l u t i o n photochemistry the  previous  studies,  radiation a  direct as  the  product.  gives This  to the s o l i d  first.  s t a t e , the  I n accordance  p h o t o l y s i s (A > 290 nm) was f o u n d only  product.  where t h e benzophenone absorbs  (A > 330 nm),  different  investigation  m u s t be f u l l y u n d e r s t o o d  b e n z o c y c l o o c t a t e t r a e n e 29c sensitization,  this  complete was  However,  essentially  conversion  subsequently  to  to y i e l d  benzophenone  a l l the i n c i d e n t a  78%  characterized  yield  assignment  is  based  mainly  on  the  NMR  spectral  of  as d i m e t h y l  2b,6b-dihydrobenzo[a]cyclopropa[cd]pentalene-2a,6c-dicarboxylate This  with  29a.  data  (Figures  2.02 a n d 2.03) . Benzosemibullvalene  29a  acetone  sensitization  to  of  by  This  compound  be  dimethyl  52%  separation,  GC. to  give  was  photolyzed  another was  1 , 6 c - d i c a r b o x y l a t e 29b w i t h t h e NMR  product  determined,  directly  and  under  a t a maximum c o n v e r s i o n after  chromatographic  2b,6b-dihydrobenzo[a]cyclo[cd]pentalenespectrum  shown i n F i g u r e  2.04.  Figure  3.03  Complete P h o t o c h e m i s t r y  Being the was  aware  solution also  of  phase  the  investigated.  Direct  photoproducts  photolysis  o f compound 2 9 c  mainly  on NMR  possibility  photochemistry  detectable  Based  of Benzobarrelene  by  of  GC.  gives,  On  secondary  of  photolysis  compound  29c  compound was  of  another  benzosemibullvalene  triplet-mediated is of  through bond  produces  an a  the  di-7r-methane initial (Figure  observed  is  suggested  photorearrangement.  vinyl-vinyl 3.04).  29a  Ring  species.  to  no  bonding closure  Reflecting  product.  i d e n t i f i e d a s d i m e t h y l 2b,6b-  dihydrobenzo[a]cyclopropa[cd]pentalene-2,6c(2aH)-dicarboxylate Racemic  led  29c  o t h e r hand, a c e t o n e - s e n s i t i z e d  a f t e r work-up, 71%  data, this  photoproducts,  benzocyclooctatetraene of  the  29.  to The  followed of  on  this the  (29e) . arise  via  selected  a  path  by  cleavage  second  biradical  other  di-jr-methane  rearrangement  possibilities  of  l e a d s t o compound 2 9 a . I t c a n the  two  vinyls  is  o f a r o m a t i c i t y from second  radical  carbonyl  and  cleavage  of  can on  be a  initial  bond  b  delocalized methylene  result,  bond  product.  In  benzobarrelenes  F i g u r e 3.04  be  onto  gives onto  position  cleavage  favored. This leads  suggested  to  of  less  cleavage  can  other  0.20,  a the  bonding.  of  bond  with  benzene  but  to  form  photoproducts  formation  than With  the  ring  resonance the  On  a  of  this  disruption  ester  other  hand,  radical  that  the other r a d i c a l stabilization.  as  As  the nature  2 9 a a n d 29b  sits a  1,3-biradical i s only  observed  from  a r e known.  Mechanism o f B e n z o s e m i b u l l v a l e n e  the  an  the  one  to  1,3-biradical  onto  more s t a b l e 29a  across  respect  gives  ring.  benzosemibullvalene  addition,  a  described route  delocalized  benzene  any  the  bond  1,3-biradical  without a  that  comfortably the  only  demanding  benzo-vinyl  step,  that  the  be  energetically  bond-breaking  w i t h one  Figure  Formation.  similar  29b  Benzosemibullvalene photochemical cleaved of  [1,3]  and  reformed  of  an  at  a  29b  as w e l l  as  from  sensitization  260  nm);  a l l three  >  limiting  photolyzed  conversion  noticeably  slower  was in  photostationary state with 29a,  a  series  monitored  were c a l i b r a t e d After 7 + 1 is  8  : :  acetone  by  in  ineffective  photochemical  the  T2  some  of  52%  state.  >  gave i s o m e r  Pure (A  290  nm)  and  GC  to  a  29a,  and once a g a i n , a  t h e o t h e r two s o l v e n t s .  steady  79-82 ^he  interconversion  benzene  were  as  a  state.  upon use o f h i g h e r suggests  energy  The  have  The  29b  compound reactions ratios  i n benzene  (Ti  been  to  and  process.  84.3  to  kcal/mole)  from  direct  kcal/mole)  excited mediate  this reaction  retarded  With  literature,most  singlet  reported  is  i n acetone  (T^^ = 69  the  the  that  = than  Benzophenone  through  : 29b  triplet-mediated.  faster  observation  a T2 mediated  :  benzene  According  sensitizers  29a  likely  proceeds  However,  occur  [1,3] s h i f t s  or  The  investigated  r a t i o . These  t h e r a t i o o f 29a  i s very  sensitizer.  [1,3] s h i f t s  of  three runs,  reaction  component  was  (octadecane).  ratio  kcal/mole)  acetonitrile.  state  standard  the arrived  benzene  than  and  the  > 260 nm)  the  acetone  is  benzosemi-  However, in  a  formation l e d to  acetonitrile  (A  29a  of  The  o f t h e two w e r e p h o t o l y z e d .  photoreaction  =  excited  sensitizers  in  u s i n g an i n t e r n a l  This  photolysis  however,  ratios  and m i x t u r e s  sensitization,^5  is  obtained.  acetonitrile  13 r u n s ,  (T]^  acetone  photolyses  3 + 1^^ a n d a f t e r  2.  by  in  from  ^o^^à  positions.  conversion  directly  come  o f a n a l y t i c a l p h o t o l y s e s . Degassed samples o f pure  compound 29b,  were  C^-Cç^ç.  to  C2a-C6c  photostationary  bullvalene  (A  the  The  limiting  interesting  was  suggested  29a.  of  between  29b  photoproduct  suspicion  shift  is  with  state, through  i s enhanced  lower  energy  hv  3.05  Figure  Mechanism  of  29e  Benzosemibullvalene 29.  benzobarrelene  suggested  upon  triplet  be The  arrived sequence o f  Bender^^ cyano is  29c,  thus  29c,  at  from  actively  accounting  monitoring.  a  [2+2]  of  a  reactions  direct  this  form  29e  for  However,  the when  the spectrum  this  from  Benzo-  signal pattern corresponding  the  benzocyclo-  cycloaddition,  a l l  process  (Figure  together with  and  29e  photoproduct  not  29d  Compound  can 3.05).  unknown;  dimethyl  the  and  cyclobutene  r e v e r t s back to c y c l o o c t a t e t r a e n e  inability  to  compound  29c  t o the  photoproduct  detected.  Interestingly,  readily  (Figure  of  rearrangement is  cyclooctatetraenes. and  is  compound,  investigating  unstable  tertiary  intramolecular  di-7r-methane to  a  excitation  c y c l o l s u t e n e 29d  from  sensitization  thermally  a n a l y z e d b y NMR, new  come  substituted  29d  GC  is  to  i s b e l i e v e d t o be  Upon  octatetraene photoproduct is  Formation  29c.  cyclooctatetraene  of  29e  Benzosemibullvalene  3.06)  detect was  its  formation  p h o t o l y z e d and  showed  cyclobutene.^^  the  from  directly  formation  of  a  2§E  2Sâ 2M 29c  29c  aromatic  29d 29d  29d  7.0  PPM  6.0  CO2CH3 CO2CH3 29d  2M  — I —  4 0  5 0  Figure  3.06  NMR  of Cyclobutene  S p e c t r u m o f Compound 2 9 c R e a c t i o n M i x t u r e  repeated  (29a, GC  29b,  compounds increases  in  and  f o r the  photolysis^^ light  29a  and  the  photolysis  of  2 9 e ) . The  formation  photoinstability The  Signals  29d.  Grovenstein's was  Showing  29e  signal of was  29e  of  of the  three  reaction the  are of  (0.013  three  formed 29b  slowed  discontinued  benzobarrelene  equal  steadily  i t s formation after  in  identified M)  photoproducts. in  29  at  photoproducts  was  monitored  by  At low conversions,  amounts. rose.  acetone  As  conversion  Conversely, higher  a l l benzobarrelene  the  conversions. 29 h a d r e a c t e d  and  the f i n a l  noticed  ratio  from  a  o f 2 9 a : 29e : 29b was  series  of  singlet  Reasoning process  concentrations of  incident  mediated  and of  the  330  30%  of  29c  is  of  the  product  seen  as  in  29  It  was  also  that the r a t i o s of  starting  comes f r o m a n  initial  processes,  higher  giving is  result,  cycloaddition. groups  is  photolyzed  nitrogen only  laser  product  2.46  The  state  direct  absorption  more  almost  singlet-  transparent  benzophenone  (A  to  sensitization  solution    a medium p r e s s u r e  =  formed  reactivity;  The  337 at  of  from  however,  diene  maximum c o n v e r s i o n yellowing  this  crystal  of  surface  the  29c same  singlet-mediated of  analysis^^  limiting  separations  and  is  via a  d i s t a n c e o f 4.1   a  Benzocycloocta-  distance  intramolecular  have  mercury  benzocyclooctatetraene  photolyses,  X-ray  nm).  a  in  center-to-center  dienes  1,7-dienes.Greater  isomerization.  with  formation  cycloadditions.Solution  a c y c l i c non-conjugated to  substrate,  a  w e l l w i t h i n the established l i m i t i n g [2+2]  29e triplet  Benzobarrelene  were  crystals.  crystalline  vinyl  9.  concentration  Extended p h o t o l y s i s r e s u l t s  displays  [2+2]  the  from  the  nm;  29  the  i n both cases.  melting  :  l o n g w a v e l e n g t h s g i v e s no compound 2 9 e .  (A > 290 nm) a n d a  tetraene  with  others  by  29e.  above  Crystals lamp  25  s t a r t i n g m a t e r i a l w i l l a l l o w f o r more d i r e c t  compound  these  but  benzosemibullvalene  radiation  wavelengths using  that  :  s i m i l a r a n a l y t i c a l photolyses  v a r i e d not only with conversion material.  65  for  and  the this  two is  intermolecular  [2+2] c y c l o a d d i t i o n s f o r double  result  in  bond only  separation cis/trans  B.  Photochemistry  of  1,4-Dihydro-l,4-ethenonaphthaIene-2,3-dicarboxyIic  Acid (40).  Direct conversion the  only  to  solution  i n s o l u t i o n a t room  Figure  3.07  of  diacid  benzocyclooctatetraene-?,8-dicarboxylic  product.  (41d, F i g u r e  photolysis  However,  this  temperature  to  d i a c i d photoproduct give  the  40  gives acid  readily  corresponding  complete (40c)  loses  as water  anhydride^^  3.07).  Photoproducts  dicarboxyllc Acid (40).  from  1,4-Dihydro-l,4-ethenonaphthalene-2,3-  Diacids are too polar laboratory.  Therefore,  the l o s s o f  starting  under  temperatures  and  mild the  ethyl 41d  two  acetate.  reaction  material.  Diacid  through  (T  <  40c  The  °C,  to  Anhydride  41d  effort  to  solution  was  synthesized  characterize  carbon-hydrogen  by  clear  yellow  cyclooctatetraenes  were  through  was  subsequently  needles  formation)  from  can  yellow 40c  in  and  40c  However,  provided  concentrated  recrystallization  diacid  29c.  was  i n the  b y NMR f o r  anhydride  diacid  color  diester  analysis  reduce  of  columns  mixture  separated  changes  GC  were m o n i t o r e d  reaction  60  forms  the  the  mixtures  f o r m s r e d - b r o w n r o d s . The d e h y d r a t i o n as  a  pass  cyclooctatetraenes  detected,  in  the  to  his  from  anhydride be  to  easily  red-brown.  by  Grovenstein^^  only  the r e s u l t s o f  report.  characterized  by  The  two  spectroscopic  techniques. An during (rate spots  interesting feature of  the =  1  °C/min)  in  the  completely further  melting  to  (•"Panhydride  =  and  is  although  occur melting solid.  solid in  inert point  is  seen  the This of  Curtin^-*"^  This proposal holds  at  a  is this  on  proposed that  rate  (A  be  40c.  Heating  of  melts  are a  at  becomes  °C  state  known, t h e y a r e of  thermal  reactions  to  No  210  solid  review  60-100 made  brown  surface.  thermal  in  noticed  crystal  the  generally,  can  photolysis  the  nature  t r u e f o r t h e above  Benzophenone-sensitized  °C,  a  was  formation  crystal  reasonable  reactant,  diacid  the  bulging  reactions  the  in 130  until  formation  the  At  reactions  solvent of  results  °C) .  and  state  °C  of  crystal.  seen  210-212  r a t h e r uncommon. P a u l organic  and  anhydride  determination  122  yellow  red-brown change  reaction,  point  this  °C  which  below  occur  the  i n the  dehydration. >  330  nm)  of  diacid  40  led  to  the  monitored were  formation  b y NMR  of  two  photoproducts.  f o r the loss of  subsequently  starting  identified  as  propa[cd]pentalene-l,2-dicarboxylic  material.  a  ratio  of  carboxylic  92  acids  :  to  8,  acid  (40b)  respectively.  elute  from  t h e r e a c t i o n s were These  two  products  2a,2b,6b,6c-tetrahydrobenzo[a]cyclo-  [a]cyclopropa[cd]pentalene-2a, 5c-dicarboxylic in  Again  and  acid  Owing  silica  gel  2b,6b-dihydrobenzo(40a,  to  the  columns,  Figure  3.08)  inability the  of  mixture  was  t r e a t e d w i t h diazomethane and the r e s u l t i n g d i m e t h y l e s t e r s (29a  and  separated  e s t e r 29a  is  and  identical  scopic this  characterized.  data  for  compound  give  NMR  to the reported r e s u l t s  originally  the  of  dimethyl  spectro-  29f i s c o n s i s t e n t w i t h the data f o r  r e p o r t e d by G r o v e n s t e i n  e t al.^*-* i n 1969.  t h e d i e s t e r s were h y d r o l y z e d under b a s i c c o n d i t i o n s  corresponding  s p e c t r a f o r compounds  spectrum  ( F i g u r e 2.02). L i k e w i s e , t h e  benzosemibullvalene  Once s e p a r a t e d , to  The  29f)  pure  diacids  4 0 a a n d 40b a r e  for  shown  characterization.  in  Figures  2.02  The  and  NMR  2.05,  respectively. With an e x p e r i m e n t diacid  40  t o the mechanism o f b e n z o c y c l o o c t a t e t r a e n e  similar  t o t h a t o f Benders^-^  with  photolyzed. routes  regard  deuterium  Similar  to the s i t u a t i o n  and  recrystallized  3.08) showed d e u t e r i u m  initial  vinyl-vinyl  were b a s e d on a s h i f t analog  (29c).  Benzobarrelene  i n F i g u r e 3.02, t h e r e a r e two p o s s i b l e  to the formation of benzocyclooctatetraene  isolated  the  performed.  l a b e l s o n t h e C-^, C 4 , C 5 , a n d C 3 p o s i t i o n s was  i n t e r c o n v e r s i o n o f d i a c i d 40c t o t h e  (Figure  was  formation,  for  reagent  NMR  labels  bonding  anhydride  41d,  analysis. in  route.  the  40c. Owing t o t h e f a c i l e  The  this  anhydride  resulting  positions  spectrum  supporting  Assignment o f the v i n y l  s t u d y p e r f o r m e d b y Bender^-^ o n  the  was  only  protons dimethyl  a)  1  4H  11+45+10  10  O  9  6+9  2+3  DMSO  2H  2H  J vJ/L 6.5  E l  5.»  .,5  ,:,  J ,  5.,  , ,  , ,  , ^  , ^  ppm  b)  • 4L.  ,Mn  ,  o  /  O  1/4D  3H{1D) DEUTERATED 41d  2H  2H  DMSO  _1 '  Figure  •••  3.08  ' 5  7.1  e.1  It  s.s  4,5  * C  /V_ Î 5  Î -  ppm  P r o t o n NMR s p e c t r a o f a ) Compound 4 1 d i n DMSO-dg. b)  D e u t e r i u m L a b e l l e d 4 1 d i n DMSO-dg.  Benzosemibullvalene from  a  bonding by  di-7r-methane to  cleavage  give of  a bond  di-TT-methane  only  benzosemibullvalene. with  40a  rearrangement  cyclopropyl a  to  route  give to  Support a l s o  the d i m e t h y l a n a l o g  (Figure  3.09) with  biradical the  (path  suggested  vinyl-vinyl  i ) . This  i s followed the  2a,6c-disubstitution (Figure  0.20)  of  comes  discussed  from  This  similar  mechanism  results  IIIA).  ( heavy circled carbons denote locations of deuterium label )  3.09  come  initial  40b  Figure  to  is  s e c t i o n (PART  product.  is  Mechanisms t o B e n z o s e m i b u l l v a l e n e s  40a  and  40b.  Benzosemibullvalene  40b,  to  The  routes  i t s formation.  vinyl-vinyl of  bond  The  b,  other  followed  (path  and route  by  subsequent to  bonding  the  determine  recombination  from  ring path  initial of  aromaticity  closure is  taken,  This  supporting is  reasonable  mixture path as  r e q u i r e much more e n e r g y .  i the  C5,  gives  shows as  the  gives  through  initial  in  and  Cg  the  product  the  NMR  of  route  of  (path i i )  40b.  step;  In  was  order  deuterium 3.09)  (Figure the  to  40b.  second  (Figure  analysis  diminution  exclusive  disruption  40  positions  cleavage  compound bonding  benzobarrelene  under benzophenone s e n s i t i z a t i o n .  signal  C4,  also  photolyzed  resulting  is  benzo-vinyl  in  the  Ci,  two p o s s i b l e d i - w - m e t h a n e  possibility  labelled  of  the  has  i , F i g u r e 3.09), f o l l o w e d by r a d i c a l  regeneration  which  first  biradical is  biradical  however,  3.10a)  H213  (0.75H)  compound  a r o m a t i c i t y i n path  and  40b.  i i would  n 4.0  "  I  1  3.8  1  1  3.6  1  .  1  3.4  ,  3.2  r3.0  ppm Figure  3.10a  Reaction  Mixture  S e n s i t i z a t i o n of Deuterated  Proton  NMR  Spectra  Compound 40 i n DMSO-dg.  from  Benzophenone  It  is interesting  semibullvalene counterpart analog the  under  favors  formation  triplet the  come  from  the  reasons  The  branching  the  second  have  step  as  not  the  well  BR2  to  has  has  only  result,  this  of  29  forms  sensitization. study  of  the  on  i n the  The  major  In  the  r a d i c a l s as efficiency  other  difference  adjacent  3.09),  addressed.  biradical are  not  and  hand,  for  carboxylic  a  BR2,  delocalizable of the  with  stability  Figure  the  whereas  center.  approach,  the of  no  carbonyls radicals  are to  less  of a c y l  findings  of  both second intermediates  (BR2  a  dimethyl triplet in  a  radicals.  acyl  radical  dibenzobarrelenes. and  efficient  involved i n hydrogen resonate  As  preference  formation  between c a r b o x y l i c a c i d s are  3.09)  2a,6c-disubstituted  this  found  reported  acids  to  clearly  d e l o c a l i z a b l e centers  formation  accordance  Figure  following discussion is  and  di-7r-methane rearrangement of  i s that  render  favors  over  compounds  m u s t be  activation  (BRI  on  on  i .  the  2 a , 6 c - d i s u b s t i t u t e d product e x c l u s i v e l y from  the  situation  should  radicals  photocycloadditions  selectivity  lowered  located  that  first  the  ester  considerations.  second b i r a d i c a l s  two  (40a).  However,  methyl  exclusively  selectivity  biradical  some p o s s i b l e  the  (path  the  H o w e v e r , Weedon e t a l . ^ - * - ^ h a v e  [2+2] ^'^c ^  Cristol  the  from  measure  that  cleavage  determining  radicals  approach  benzosemibullvalene ester  the  both  one  on  b  benzo-  2a,6c-disubstituted  product  bond  established.  Examination of BR3  Recall  bridging  comes  Factors  attempt to shed l i g h t  shows  of  its  established  vinyl-vinyl  involved  methods  been  Having  i n 1,2-disubstituted  to  sensitization.  increase  biradical.  understood  compared  product.  initial  for  increase  2a,6c-disubstituted  1,2-disubstituted  both  an  diacid  to note the  onto and  BR3)  the  esters at  in  this  stabilizing  bonding.The acid  comparable  carbonyl in  their  ablllties  t o form.  I n a d d i t i o n , b o n d b may p o s s i b l y b e more e a s i l y a.  I t has  rings, are  similar  not  it in  only  flaw  adjacent  to  i n using  crystallographic  a  (Figure  c o v a l e n t bond  3.10b).95  analyses  strength.  whether  This  However,  i s  the  cyclopropane  idea  of other  a  major  t h e r e l a t i v e bond s t r e n g t h s  bond  factors  t h i s model i s t h a t t h e  (BRI) i s i n t h e g r o u n d s t a t e . A n o t h e r from  than  ( b o n d b) when o t h e r  I t was c o n s i s t e n t l y n o t i c e d t h a t b o n d b  bond  i s unclear  to favor ^-cleavage  The  comes  benzobarrelenes.  relative  •  considered  than  that e x c i t e d carbonyls  t o BRI, t e n d  mentioned  longer  reported  present.  biradical be  been  cleaved  i s good  that  2,3-diacyl  substantially indication of  drawback  will  may  is  that  remain unchanged  BRI.  O  Compound X  =  Y  =  OCH3  X  =  Y  (Cl,  Figure  3.10b  C5,  were  47  b o n d b (Â) 1.542(8) 1.536(2) 1.532(3) 1.536(3) 1.540(3)  Cg = C H 3 )  T a b l e o f Bond " a " a n d " b " L e n g t h s f r o m X - r a y A n a l y s i s .  In a s o l i d 40  43 44 45  == O C H 3 C4,  1.520(1) 1.519(2) 1.517(3) 1.522(3) 1.530(4)  29  X = P h , Y = OMe X = Ph, Y = OEt X = Ph, Y = O i P r  b o n d a (Â)  s t a t e photochemical study,  photolyzed  until  they  crystals  of  benzobarrelene  became y e l l o w w i t h s l i g h t m e l t i n g o n t h e  surface  (4 and  crystals  15 h o u r s ) .  showed  change  in  no  no  resulting  photoproducts.  physical  absorbed,  The  appearance  singlet  or  NMR  spectra  Although  confirm  triplet  generating  heat.  d e a c t i v a t i o n as Many as  acids  arising of the  in  have  were  have  the been  detected.  internal  also  and  The  conversion,  contributed  to  the  the  dimers  through  hydrogen  s t a t e i n f r a r e d spectrum of the  bonding^^ starting  a l s o i s hydrogen bonded. R a t h e r t h a n  carbonyl  region,  symmetric  and  there  are  asymmetric  material a  single  several absorption stretching  and  bands  frequencies  dimer.  the  hinder  a  crystalline  molecule the  substituents.  40  formation  that  the  cannot 3.11b,  It  proposed  binds  reaction  moves  Although,  reasonably  bonding  that  reaction.  benzobarrelene  Figure  in  solid  the  from  In  be  exist  3 . 1 1 a ) , compound 40  absorption  from  dissolved  analysis  photons  photoproducts  may  the  well.  evidenced i n the  (Figure  of  Fluorescence  UV  that  e x c i t e d energy i s s u g g e s t e d to have d i s s i p a t e d  of  between the  most  the two  in  reasonable  restricting  to  assume t h a t t h e p o r t i o n s  X-ray  crystal  data  the  strong  place.  most  appendages This  anchoring vinyls.  are  of  the  is  available,  intermolecular to  the  acid  in  carboxylic  not  situation the  will  portion  reaction  the  that  the  a  move  carbonyl  take  where  is  environment,  lattice is groups  turn of  acid i t can  hydrogen such  that  depicted  in  prevents  bond  Figure  3.11 a) S o l i d S t a t e  I n f r a r e d Spectrum o f D i a c i d  b) Simple R e p r e s e n t a t i o n  o f the R e a c t i o n  Showing the Hydrogen Bond Anchors.  AO.  Cavity  of  Diacid  40  Support by  Scheffer  for  et  disubstituted  this  a l . ^ ^ on  argument the  rearrangement,  66  they  (Figure  found  of  the  acid essentially  prevents  in  the  solid  H-bonds a n c h o r i n g  motion  required  p r o d u c t 66b 95  :  s t a t e . The  5.  in  initial  from the  initial  In  significant  solution,  ester  however,  side  on  recent  of  publication  ester/acid  3.12).  Focussing  intermolecular  b o n d i n g on the  a  acid the  bonding  intermolecular  the  restricts  i)  H-bonding  the  (path i i )  a c i d s i d e . As (path  on  H-bonding  acid side  group  vinyl  a  is plays  the  result, favored a  less  role.  a) b) c) 3.12  barrelene  initial  that  bond f o r m a t i o n  fîga  Figure  from  photochemistry  dibenzobarrelene  di-TT-methane  comes  in Solid State 0.01 M in benzene in NaHCOg  Hydrogen Bonding 66.  ggjj  Ratio  5 72 90  : : ;  95 27 10  Effects  on  the  Photochemistry  of  Benzo-  C.  Photochemistry  Anhydride  of  (41).  Anhydrides silica  gel.  resonance and  1,4-Dlhydro-l,4-ethenonaphthalene-2,3-dicarboxylic  In  was  are  unstable  to  the photochemical  the key  factor  chromatographic  study of anhydride  i n the assignment  of  separation  on  41, n u c l e a r magnetic  photoproduct  structure  ratio. On  ethyl  an  acetate  products,  analytical and  scale,  benzene  independent  characterized  to  of  anhydride  anhydride^-^  and  mixture  the is  reaction  shown  in  conversion three  photolyzed to  in  three  photoproducts  (41a),  were  naphthalene-2,3-dicarboxylic  2 a , 2b, 6b, 6c - t e t r a h y d r o b e n z o [ a] c y c l o p r o p a  pentalene-1,2-dicarboxylic of  complete These  was  2b,6b-dihydrobenzo[a]cyclopropa[cd]pentalene-  2a,6c-dicarboxylic  GC-MS  41  solvent.  as  (41b),  give  anhydride  anhydride mixture.  Figure  (41c,  The  3.14.  NMR No  Figure  3.13)  spectrum  of  by the  benzocyclooctatetraene  NMR  [cd]and  reaction 41d  was  assignments,  a  detected. In  order  to  confirm  preparative  scale  mixture  anhydrides  of  dimethyl then  with  column as  esters  by  photolysis was  chromatography  benzosemibullvalene  and b e n z o s e m i b u l l v a l e n e  The  on  29f  was  performed  the  to  NMR and their  photolysate  first  diesters  were  three  silica  29a,  initial  converted  reacting  diazomethane.  the  gel  dimethyl  ( F i g u r e 3.13).  and  independently  the  resulting  corresponding with  methanol,  separated  by  characterized  naphthalene-2,3-dicarboxylate,^'^  Flgure  3.13  Photochemistry of Benzobarrelene Anhydride  41.  Figure  3.14  Photolysis.  NMR  Spectrum  of  A n h y d r i d e 41 R e a c t i o n M i x t u r e  from  Direct  The conversion than  reaction as  some  others.  products  is  standardization. ratio  were  photoproducts  Direct too  ratios  quantum  difficult  noticed  measurement  the products  is  to  carefully  of  more  these  of  monitor  accurate  the  plotted  in  Figure  w e r e s t a n d a r d i z e d b y NMR conversions, as  the  the 41a,  the  signal  other  3.15. GC i n t e g r a t i o n r a t i o s t o be r o u g h l y  error trace  two  in of  GC  41b  signals.  A  4 1 b , a n d 4 1 c was d e t e r m i n e d  F i g u r e 3.15 a t l o w c o n v e r s i o n  Figure  3.15  Plot  S t a r t i n g M a t e r i a l Conversion.  integration  f o r GC  r e a c t i o n r a t i o s as a 20  readings  o f 41a, 41b, and 41c At  higher  may be s u b s t a n t i a l l y  greater  very  broad  relative  rate  of  : 19  :  t o be 25  rapidly  anhydride  respectively.  appears  (ca.  of Anhydride  1 : 1 : 1 ,  the  photoproduct  f u n c t i o n o f c o n v e r s i o n . T l i i s was done b y GC a n d t h e r e s u l t i n g were  with  c o u l d n o t be p u r i f i e d  The n e x t m o s t e f f e c t i v e m e t h o d  determination  fluctuate  undergo photodecomposition  yield as  to  and  overlaps  formation 56  from  of the  with  products graph  of  10%).  Photoproduct  Composition  as a F u n c t i o n o f  Triplet of  starting  compound of  the  41c, as  by  material  41c two GC.  sensitization  rapidly at  a  The  t h e r e i s no  rearrangement  that  to  the  starting between  suggested  t o come  (Figure  3.16).  indicate  routes,  (path  ii) .  material the that  in  other  1,2-disubstituted  bridging  taken.  conversion  v i n y l - v i n y l bonding  di-TT-methane  upon (ca.  this  two  the  36  two  labelled  photolyzed Again  the  vinyl-vinyl  to  of  much  ratio 41a  to  greater  benzosemibullvalenes  triplet-mediated  benzosemibullvalenes  The  64  is  However,  GC.  41a  ( p a t h i ) f o l l o w e d by bond  Selectively  41c.  :  ratio  Benzosemibullvalene  bridging  routes.  initial  from  is  i n the the  and  conversion  photolysis.  determined  systems,  complete  41a  12%)  vinyl-vinyl  was  gave  further  i n t e r f e r e n c e o f compound 41b  study are  initial  low  acetone  benzosemibullvalenes  decomposes  confidence  Similar this  to  using  can  (path  a be  comes  formed or  (Cj^, C 4 , C 5 , a n d determine  di-7r-methane  cleavage.  i)  positions  bonding  is  the  from Recall  from  two  benzo-vinyl Cg  the  labelled  in  positions) preference  o f compound only  41c  pathway  Figure  3.16  In  Pathways t o Photoproduct  both  semibullvalene  direct  41c  benzosemibullvalene (41c) formed come  from  from  approximately  delicate  biradical  twice  as  fast  benzoas  calculations^^^ product  between  on  favor  (41a). the  study.  Both  41a  the  product and  41c  ( B R I ) . The s t a b i l i t y b e t w e e n t h e two  (BR2 a n d BR3) b a s e d  balance  photolyses,  The r e l a t i v e amount o f 1 , 2 - d i s u b s t i t u t e d  t h e same i n i t i a l  MM2  from A n h y d r i d e 41.  triplet-sensitized  i s even h i g h e r than i n the d i a c i d  2a,6c-disubstituted very  formed  41a.  secondary b i r a d i c a l s and  is  and  Formation  It  both  radical  BR3, is  leading  suspected  formation  of  that  these  delocalization to  the  there two  minor is  a  benzosemi-  bullvalenes  and  selectivity. immediate further  subtle  Also,  factors  the  notion  branch-point complicate  suggestions  are  the  in  in  PART  IIIB  of t h i s  propane  rings  adjacent  On  the  conjugated  be  adjacent  vinyl.  of  conjugation  (29)  to each  hand,  to  the  too  two  in  cyclic  the  methyl  the  increase  in  tendency f o r bond b  /9-cleavage  ^^d on  of  cyclo-  relative  lengths  anhydride  rigid  esters  (41)  and  stabilization  BR2  formation  five-membered  o f 29  simultaneous  the  to  are  the  a t t a i n e d by  are ring.  shown f r o m X - r a y  conjugation  contributes  (41b),  i t was  sensitization  the  formation  noted  that t h i s product  of  a  cycloaddition  Diels-Alder  therefore,  i t  from  seems a  benzobarrelenes  reasonable  reverse  Owing t o i t s v o l a t i l i t y , NMR  spectrum  the  to  to  the  regeneration  the  increase  [4+2]  Figure  naphthalene - 2 , 3 - d i c a r b o x y l i c  41;  in this  of  an  that  i s not this study  this  not  3.14  observed  to  naphthalene  isolated.  from  indicates a were  acetylene  cycloaddition  a c e t y l e n e was in  of  benzobarrelene  The  the  s e l e c t i v i t y . Anyhow, some  the observed  by  for  mediated process.  of  rationalize  biradicals  formation.  anhydride  formed  to  both  i s t h a t the c a r b o n y l s o f the anhydride other  bulky  Perhaps  Turning  triplet  this  to e x c i t e d carbonyls^^.98  compound  analysis  i n 41c  of  major d i f f e r e n c e between t h i s  other  this  and  b i n a n a l o g o u s compounds ( F i g u r e 3 . 1 0 b ) .  ester  efficiently  (BRI) are  t h e s i s t h a t the  maybe i n c r e a s e d b a s e d o n  dimethyl  BR3)  product  formation.  t o BR2  One  alter  precursor  and  attempt  cleavage  o f bond a and  the  (BR2  understanding  forwarded  drastically  that  species  1,2-disubstituted product Recall  can  along  with  by  naphthalene;  derivative  However,  shows a 2 - p r o t o n  singlet-  synthesized a  the  is  acetylene. examination  (relative  to  the  signal This  I n t e g r a t i o n o f naphthalene d e r i v a t i v e signal  arises  may  as  the  Diels-Alder  likely solvent  the  yellow 38  two  crystal  little  solid  no  X-ray  from  products,  almost  a  singlet  known  to  at  2.20  ppm) . •'-'^•^  at  2.07  occur  ppm.  Uncertainty  ppm.  Reverse  photochemically  barrelene  photolyzed  (A  light  yellow  the  reaction  from  analysis at  the  state selectivity of  were  changed  41c  twice  41  41a  the  that the anhydride  the  (2.3  benzosemibullvalenes  NMR  o f 41a t o  analysis  suggested  has  been  anhydride  cracks.  : 62 r a t i o in  of  appearance  with  formed  have  acetylene  singlet  i n  systems.-^^^  Crystals give  from  acetone  reactions  other barrelene  to  be  41b)  of  8%  conversion.  abundance  of  and  starting portion of  skeleton  the  enough  to  to  was  nm)  hours);  cloudy  dark  showed  compound  a  41c i s  41a. Thus t h e r e i s formation.  Although  performed,  i t c a n be  molecule be  (13  mixture  compound  material  260  41c  Again  i n benzosemibullvalene  >  does  affected  not  by  protrude  the  lattice  upon r e a c t i o n . It not  i s interesting  detected  in  the  eliminated acetylene The  lattice  is  for recombination  tight  solution  lattice.  For  example,  to leave reactions and  these  the  enough  runs.  to  systems many  drastically  reaction  from  state  the  Type  p o s s i b l e reason  the  This  "cage has  I  cleavages  altered  because  In  I process  fact  the  crystal  relevance are  the only  i n  made  lattice.  few  cage e f f e c t s .  i n place  originally  the  crystal  competitively  fragments a  was  i s that the  e f f e c t , "•'-^^  have been r e p o r t e d  a r e shown t o h a v e s t r o n g l a t t i c e  41b  eliminated species  also  Type  c a v i t y . •'-^^  A  t h e cage o f  hold  t o the naphthalene.  to  or  solid  i s unable to leave  applied  unfavorable  t o note that the naphthalene d e r i v a t i v e  are  unable  decarbonylation  i n the s o l i d  state  D.  Photochemistry of  In idea  the  is  study  that  favored  in  2,3-diben2oyl-l,4-dihydro-l,4-ethenonaphthalene  of  2a,6c-disubstituted  solution;  semibullvalenes  however,  is  rigidly It  this.  So  fixed  i n a conjugated  i s necessary  f a r , two  formation  and  o n l y one  another  substrate  delocalize  Also  p r e f e r r e d as  the  the  t o be  a The  efficient  a result,  synthesized. triplet  intention  to  excite  Direct photolysis gave  pentalene  as  However,  (42a)  higher  be  carbonyls  vinyl.  product  2a,6c-disubstituted  appropriate and  can  to  crossing  to  triplet-mediated.  the  product  triplet  Direct  (A >  is  photolysis  t h e s e di-7r-raethane  also allow  have  efficiently  2a,6c-disubstituted  reactions  state.  that the  group  is  absorbs  similar  to  radiation  barrelene  (42)  acetophenone,  above  system to the  chromophore f o r a di-7r-methane  acetonitrile  only  side-chains  enhance  intersystem  benzoyl  sensitizer  t h r o u g h the b e n z o y l  the  2,3-dibenzoyl-1,4-dihydro-l,4-ethenonaphthalene The  is  radical  1,2-disubstituted  would  carbonyl  to  excited state w i l l solid  increase  It  reaction i s  i n v e s t i g a t e d i n the  known  bulky  benzo-  weaker  where  adjacent  system that gives  studied.  radicals  subject  triplet  As was  t h a t has  adjacent  formation.  to  have been  generally  another system to f u r t h e r i n v e s t i g a t e  systems t h a t  carbonyl  with  anhydride  system to the  are  the  1,2-disubstituted  carbonyls  cyclic  to synthesize  carbonyl  product formation  formation  from  from the  benzobarrelenes,  benzosemibullvalenes  the  increased  s t a b i l i z i n g p r o p e r t i e s or are  2,3-diacyl-substituted  (42).  330  nm.  triplet  state  reaction.  330nm) o f b e n z o b a r r e l e n e 42  in  benzene  or  2a,6c-dibenzoyl-2b,6b-dihydrobenzo[a]cyclopropa[cd]-  the  only product independent of  reaction  conversions  led  solvent to  the  (Figure  3.17).  formation  of  1,6c-dibenzoyl-2b,6b(2aH)-dihydrobenzo[a]cyclopropa[cd]pentalene as  a  secondary  photoproduct  are c h r o m a t o g r a p h i c a l l y was  characterized  expansion in  the  patterns  in  a  mixture is  shown  therefore,  with in  42a.  compound Figure  Compound  42a.  3.18.  The  The  excess  sensitizer  o f the  benzobarrelene trace  42c  42  a  gave  detected.  benzophenone-sensitized (absorbs complete  ca.  75%  of  conversion  spectral  proton  pattern  w i t h the reference  Benzophenone  was  reaction. incident to  removed  Photochemistry  of Dibenzoyl Benzobarrelene  was  18-molar  radiation)  easily  42.  42a  An  compound  chromatography.  3.17  42c  NMR  shown i n PART I I . On t h e o t h e r h a n d , b e n z o s e m i b u l l v a l e n e through  Figure  42a and 42c  benzosemibullvalene  spectrum o f the s e m i b u l l v a l e n e r i n g agrees  characterized  only  compound  inseparable;  o f the mixture NMR  from  (42c)  42a by  to with  column  Figure  3.18  Characterization  M i x t u r e w i t h 42a,  by  NMR.  of Dibenzoyl  Benzosemibullvalene  42c  in  Similar  to the p r e v i o u s  semibullvalene  42a  through  initial  (Figure  3.19).  i s suggested  vinyl-vinyl This  solution photolysis stituted radicals over  is  supporting  the  f o r m a t i o n o f compound 42a regression  graphed  i n Figure  Figure  3.19  Benzobarrelene  that  from a di-7r-methane  calculations  by  benzo-  rearrangement  bond  a  cleavage  the  only  primary photoproduct  idea  that  carbonyls  can  efficiently  (std.  dev.  outlined  on  in  The =  quantum 0.04),  adjacent formation  yield  f o r the  determined  the expermental  from  2,3-disub-  stabilize  benzosemibullvalene  benzosemibullvalenes. i s 0,10  2a,6c-disubstituted  followed  as the  the  2a,6c-disubstituted  1,2-disubstituted  linear  to form  bonding  formed  benzobarrelenes enhance  studies,  section  from and  3.20.  Mechanisms (42).  to  Photoproduct  Formation  from  Dibenzoyl  Benzosemibullvalene o f compound 4 2 a , observation  that  sensitization higher  and  comes  a g a i n t h e two  this  in  a  a  [1,3]  photochemical  photostationary  i n t e r c o n v e r s i o n does not p r o c e e d that this  shift  triplet  process.  The  determined  from  are  indicates  energy was  42c  6 :  t o be  may  be  42a  42c  state.  The  w i t h benzophenone  either  to  shift  a  singlet  or  a  photostationary state  4.  0.3 <D = 0.10  ( std. dev. = 0.04 )  0.2 X X  0.1 X  X  0 0  5  10  15  % conversion  Figure (42)  8% a  G r a p h o f Quantum Y i e l d  ($) o f  42a  versus  Starting  Material  Conversion.  15 a n d by  3.20  NMR and  Crystals  of  45 h o u r s ;  the  to 14%  show  After  prior the  resulting  a  1  :  1  scale to  reaction,  the  were  photolyzed  yellow  (A > 290  crystals  r a t i o of benzosemibullvalenes  photolysis.  photolysis  42  unmelted  conversion, respectively.  preparative  crushed  benzobarrelene  to  Compound 42b Crystals achieve  photolysate  of a  was  42a  obtained  and  4Zb  at  pure  from  42  were  conversion  passed  for  analyzed  benzobarrelene  higher was  were  nm)  through  (38%). three  successive pure  chromatography  columns,  rearrangement  with  cleavage  shown  solid  as  state  of  which  yielded  9%  of  42b  initial i n  i s  s u g g e s t e d t o come f r o m a d i - j r - m e t h a n e  vinyl-vinyl  Figure  reactivity  here  approaches  to  3.19. i s  bonding The  that  followed  interesting  compound  42b  by  bond  feature i s  of  not  b the  observed  solution. Two  The  first  approach  relates  formation-electronic lattice bond,  of  thus  during  presence of  that  or  42b  large  by  crystal  i s  the  this  benzoyl  validity into  will  As As  crystal  these  the s o l i d  state  discussed,  i n the c r y s t a l double  delocalize the  involves the  lattice  that  move could  be  affected  of  explaining crystalline  Introduction  available  approaches.  these  can  substantially  the  behavior  the  formation  in  was  using  to  selectivity  method  two  taken.  i t i s reasonable t o imagine  required  described  data  to  explain  the  result,  used  be  photoproduct  The s e c o n d a p p r o a c h  with  are  of  groups  groups  could  state.  a  crystal  of  be  factor  groups  widely  X-ray  these  o f t h e two p a t h w a y s ;  lattice.  most  No  investigation barrelene  either  benzoyl  can  the adjacent carbon-carbon  of  solid  results  determinants  bulky  interactions  reaction.  the  reactivity. test  The  This  the  solution  ability  the  specific  the  the  i n  enhance  the  the  reaction.  during  this  to the  effects.  lowering  compound  deter  explaining  c o u l d be o u t o f c o n j u g a t i o n w i t h  radical  of  last  42b. Benzosemibullvalene  in  the  in  However,  of two  section,  this  case  a more  2,3-disubstituted approaches,  state to  detailed benzo-  i n PART I V  thesis. Concluding the  from t h e di-7r-methane  solution  study  rearrangement,  of  initial  benzosemibullvalene bridging  formation  o f the2,3-dicarbonyl  benzobarrelene aromaticity subtle the  i s exclusively vinyl-vinyl in  benzo-vinyl  i s the s e l e c t i v i t y reaction  however,  formation  inefficient  at  Generally,  are of  favored  the  delocalizing  are used as s u b s t i t u e n t s .  requires  e x h i b i t e d i n the  pathway.  benzosemibullvalenes  bonding  i n nature,  latter  second  formation  over  the  product  adjacent  as t h e  too  much  disruption energy.  bond-breaking of  radicals  More of  2a,6c-disubstituted  1,2-disubstituted is  step  of  products;  i n c r e a s e d when c a r b o n y l s or  a  cyclic  anhydride  PART I V .  A.  PHOTOCHEMISTRY  Photochemistry  OF UNSYMMETRICALLY D I S U B S T I T U T E D BENZOBARRELENES  of Methyl  2-Benzoyl-1,4-dihydro-1,4-ethenonaphthalene-  3-carboxylate (43).  Success along in for  with  the  in some  achieving interesting  dibenzoyl  system,  investigation.  substituents efficiently  can  The be  As  inspired  easily  a  the was  result,  to  yet  the  was  this  the  di-TT-methane  rearrangement.  i s now a n u n s y m m e t r i c a l  Furthermore,  different  direction of  initial  possible  benzosemibullvalene  ment ( F i g u r e 4 . 0 1 ) . must can be  be  understood  probed.  Again, first  this  system  system  whereby  ability  s t a t e upon  to  direct  effect  from  benzoyl  group  substituent  prepared  in  the  A  i s  effects  i t must be r e c o g n i z e d t h a t  also  solution  before  next  the  to study  can  products  the  photochemistry  the  excited  synthesized.  benzobarrelene,  bonding;  of  photolysis  2-benzoyl-1,4-dihydro-1,4-etheno-  However,  regioisomers  state  retain  triplet  methyl  (43)  direct  solid  design  r e t a i n e d a n d t h e e s t e r c a n e a s i l y be a l t e r e d on  from  to study a s i m i l a r  altered  cross  naphthalene -3-carboxylate  products  triplet-mediated  objective  intersystem  irradiation.  triplet  arise  the  i n  racemic  depending  doubles  the  di-TT-methane  photochemistry  of  form. on  the  number  of  rearrange-  this  behavior i n the c r y s t a l l i n e  system state  B Initial Benzo-Vinyl Bridging  F i g u r e 4.01 3-Ester  P o s s i b l e Di-7r-Methane Rearrangement Pathways f o r the 2-Benzoyl  Benzobarrelene.  Direct acetonitrile, Overlapping  photolysis  of  or  hexanes  gave  signals  and  of  from u s i n g the  DB-1  product  determination  ratio  and  determination  six  by  in  the  independent  8  ratios  were  thus  are  this  determined  : t r a c e o f compounds 4 3 a , Isolated  methyl  from  43b,  direct  43h,  methanol,  of  of  prevented  solvent.  the  products  accurate  reaction  sufficiently  to  43c,  photolysis  separated  i s shown i n F i g u r e 4.03,  assignments are c o r r e l a t e d w i t h the s p e c t r a o f product  benzene,  However, the s i n g l e p r o t o n s i g n a l s NMR  integration;  in  decomposition  columns  b y GC.  43  products  thermal  carbowax  the s e m i b u l l v a l e n e products ratio  benzobarrelene  pure  be  50  43d,  and  by  samples. :  25  :  and  The 17  of for the  photo-  : trace :  43e.  column  chromatography  are  2 a - b e n z o y l - 2 b , 6 b - d i h y d r o b e n z o [ a ] c y c l o p r o p a [ c d ] p e n t a l e n e - 6c -  carboxylate  (43a)  and  methyl  6c-benzoyl-2b,6b-dihydrobenzo[a]cyclo-  propa[cd]pentalene-l(2aH)-carboxylate c o n s i s t e n t w i t h the  established  semibullvalene  was  43a  needles  and  prisms,  points  and  carbonyl  IR:  e s t e r C=0  114  °C,  IR:  1733  their  1723  1674  these  two  marked  frequencies  b e n z o y l C=0  spectral  for  to possess  by  stretching  cm^^,  e s t e r C=0  patterns  noticed  verified  (43b);  cm''^, b e n z o y l C=0  crystalline differences  1677  and  are  structures.  (needles,  cm'^  data  MP  prisms,  cm'^) .  Benzo-  morphologies, in  melting  = 106-107 MP  =  °C, 113-  F i g u r e 4.02  Photochemistry of Benzoyl Methyl Ester Benzobarrelene  43.  Figure barrelene  4.03 43  NMR  Spectral  Expansions of  R e a c t i o n M i x t u r e from D i r e c t  the  Benzoyl Methyl Ester  Solution Photolysis  in  Benzo  CDCI3.  T r i p l e t - s e n s i t i z e d photolysis of benzobarrelene analytical  scale  sensitizer  (absorbs  (A > 330 nm)  was  photoproducts,  with  a  10-fold  ca.  85%  monitored  molar  of  b y GC  excess  incident  of  and m e t h y l  increased,  diminish  and  results  in  were  observed.  Extended  direct solution  starting excess  in  minimiim  over  the  allowed  surface to  photolyzed  was  monitored  The  resulting  to  give  scale of Flash  a  by ratio  was  43e.  much  slower  large  Pyrex  by  The  photolysis  the  major  conversion  photoproducts  similar  GC  The  at  trace to  tube  as  to  gave  no  43h  43b  :  same  ratio.  that  in  mixture could  and  12  repeated  the  the  the  conversion  in  the of  of  43a, at  43b, -50°C  The p r e p a r a t i v e  for  the  surface the  film.  first  band  second isomers  be  remained.  inner  support  43a  solvent reactant  material 12  spread  the  housing  w/w (PMMA)  was  and  was  compound  inseparable compound  as  10-fold  mixture  slides  :  except  used  benzosemibullvalene an  the  above was  This  temperature  30  experiment  a  scale,  methacrylate]  starting :  experiment,  analytical  with  film  room  12  reaction  same  clear  no :  different an  microscope  nm)  34  chromatography  t h i r d band c o n t a i n e d Interestingly,  the  As  a  poly[methyl  residual  until  On  chloride.  Pyrex  290  GC  was  followed  >  and  column  benzophenone as  other  a  together  weight  methylene  The  from  media.  dissolved  three  (A  procedure a  of  of  isolated  matrix  molecular  evaporate.  43d,  43h was  was  amount  was  43h,  43  medium  in a  photolysis  polymer  material of  to  an  photolysis.  Benzosemibullvalene photolysis  began  on  6c-benzoyl-2b,6b-dihydro-  (43h).  43h  done  f o r m a t i o n o f two  benzo[a]cyclopropa[cd]pentalene-2a-carboxylate compound  was  radiation).  t o show t h e i n i t i a l  b e n z o s e m i b u l l v a l e n e 43a  43  43d  isolated,  band.  The  and  43e.  although  this  compound  This  is  was  because  detected  in  compound  the  43h  GC  of  thermally  a t 200 °C g a v e  to  GC  43h  and  therefore  the  >  290  nm)  in  a photostationary  detection  benzene  state.  and  the  partial  43b  is  The 8 : 2  ratio  (A > 290 nm)  i n benzene,  acetonitrile,  conversion  of  GC  methyl  above  artifact  of  solvent. Similarly,  20%  by  benzene  compounds  benzosemibullvalene and  (corrected  (43c),  shown  in  independent, but the rate o f slower.  of  to confirm  acetone  for  by  Photoproduct followed  Independent  43c by  was  of  Figure  the existence o f 43b  to  43h  is  photolyzed  give  a  response  in  isolated  maximum by  NMR)  acetone  reaction was  is  solvent  noticed  to  be  from a l a r g e r s c a l e p h o t o l y s i s i n  successive compound  The  chromatographic  43c  separations.  gave compound 43a w i t h  t h e same  o f 43a t o 43c.  Compound 4 3 a comes f r o m a t r i p l e t - m e d i a t e d d i - j r - m e t h a n e initial  vinyl-vinyl  bond  (path  i i , Figure  bond  a  give  comes  and  4 3 a was  detector  4.02.  conversion  two  photolyses  : 2 ratio  via  photolysis  l-benzoyl-2b,6b-dihydrobenzo[a]cyclopropa[cd]pentalene-6c(2aH)-  carboxylate  43h  GC  rearrangement  an  interconverted  acetonitrile  of  8  of  43b a n d 4 3 h w e r e  independent  to  only  in  mixture.  decomposition. Benzosemibullvalenes  (A  reaction  rearranges  200 °C t o g i v e 4 3 b ; i n j e c t i o n s 43b,  the  to  from  the a  bond  formation  gives  the product. Compound  on  43b  benzosemibullvalene  bridging 4.01).  observed  di-7r-raethane  This  43h,  a  the is  product.  followed Similarly,  (path  with  side by  of  the  initial  [1,3] cleavage  the double  cleavage  of  benzosemibullvalene initial  vinyl-vinyl  i ) ; subsequent cleavage  photochemical from  benzoyl  rearrangement  the ester side  is  on  rearrangement  shift of  o f bond a  product C2g^-C^^  of bond.  The  reaction  reaction  proceeds  as  on  direct  photolysis  and  i t competes w i t h the s u b s t r a t e f o r r a d i a t i o n .  is probably a singlet-mediated process. Likewise, comes  from  a  r e a c t i o n was  acetone  similar  photochemical  also noticed  t o be  [1,3]  slower i n  slows  the  Therefore,  this  benzosemibullvalene  43c  shift  of  acetone,  compound 4 3 a .  indicating  a  The  singlet  reaction. The  suggested  experiment; placed the This  the ^3'  agrees  spectrum 43b  photolysis  on  C2h'  mechanisms  C-^,  C4,  of the  benzobarrelene  Cg^^ the  ^6'  ^^'^  redistributes  labels  the l a b e l s  benzosemibullvalene  label  also  labelling  deuterium  i n F i g u r e 4.01.  the  ^6h^  a deuterium  with  on  route  mixture,  by  43  positions  proposed  reaction  ^3'  supported  C 5 , a n d Cg p o s i t i o n s  '^6' with  (^2h'  of  are  supports  the  43a.  F r o m t h e same  distribution  to  NMR  on  compound  reaction  sequence  proposed. In contrast, are  formed  in  the 1 , 2 - d i s u b s t i t u t e d b e n z o s e m i b u l l v a l e n e s (43d and  t r a c e amounts f r o m d i r e c t p h o t o l y s i s  T h i s agrees w i t h the such  as  benzoyl  paths  i and  findings  and  i i ) to  ester form  in favor  key  method  on compounds 4 3 a of  their  [1,3]  a,y8-unsaturated their  43a,  the  that  comes  not  Carbonyl 30  counterparts.-*-^^  43c,  and  43.  substituents (Figure  4.01,  benzosemibullvalenes  over  relative  from  about  frequencies  carbonyl  cleavage o f bond a  the  isomers. are  of benzobarrelene  1,2-disubstitution.  assigning  43h  esters  stretching  compounds  to  shift  saturated  carbonyl of  and  III  2a,6c-disubstituted  the c l e a v a g e o f bond b t o g i v e the The  PART  43e)  at 43h  NMR,  substituent but  from  stretching  about have  1730  IR  analysis  frequencies  wavenumbers Saturated  positions  lower  than  esters cm"-*-;  stretching  the  of  have ester  frequencies  at  1723  cm'-'-,  ester  1726  carbonyl  presence  and  (Figure  of  compound  yields  43h  4.04).  ($)  were  respectively.  stretches  at  determined  formation  at  squares  calculations  actinometry,  benzosemibullvalenes 0.02),  and  respectively.  di-TT-methane each  43a  rearrangement other,  indicating  primary  the  extrapolated  to  and  zero  graphed  conversion  to obtain the reported values.  the  quantum  43h  a r e 0.14 ( s t d . d e v . 0.01) a n d 0.13  The  quantum  products a  lack  yields  yield are  formation  values  well  benzoyl  s i d e and t h e e s t e r s i d e f o r s o l u t i o n phase i n i t i a l  43a  of  for  of  compound  photoproducts  conversions  limits  for  within  preference  the error  between  the  bonding.  compound 43tl 0.3  0.3  «I> = 0.127 ( std. dev. = 0.023 )  4> = 0.138 (std. dev. = 0.012]  0.2  0.2  -^x  0.1  0  1  0.1  2  3  4  5  1  6  % conversion  Figure for  However,  1 7 0 3 cm"-*^ i n d i c a t i n g t h e  of  different  least  valerophenone  dev.  f o r the  were  Using  two  43b  cm"^,  results  linear  (std.  1718  The  using  of  and  o f a,/9-unsaturation.  Quantum 43a  cm'^,  4.04  Plots  the Formation  3  4  5  % conversion  o f Quantum Y i e l d v e r s u s  of Benzosemibullvalenes  2  Conversion  of Starting  43a and 43h i n Benzene.  Material  Having  established  of  benzobarrelene  the  solid  the  resulting  state.  43,  NMR  conversion  compounds  (ca.  20%)  >  290  melting  analysis  led  to  until  43  GC  the  to  give  methyl  6b-carboxylate  be  were  show  photolyzed  the  crystals  showed  a  o f 50 : 30 : 20.  4.05.  crystals were  of  yellow  resulting  to and  the formation o f three  mixture  Figure  extended  Higher  43  mixture  43a  photolyzed  s h o w e d no s i g n o f  was  o v e r l a p p i n g bands; the f i r s t  NMR  conversions  were  but  17%  was  chromatographed rechromatographed  6c-benzoyl-2a,2b-dihydrobenzo[a]cyclopropa[cd]pentalene(43f,  benzosemibullvalenes effort  to  reaction  scale,  ( c a . 1 8 % c o n v e r s i o n ) . The  give three p a r t i a l l y  of  benzobarrelene  now  behavior  s u r f a c e m e l t i n g a n d d e t e c t a b l e a m o u n t s o f compound  to  extra  can  43d, 43e, and 4 3 f i n a r a t i o  On a p r e p a r a t i v e  nm)  photochemical  investigation  by  of  phase  o f t h i s m i x t u r e a r e shown i n  began t o form. (A  of  analyzed  photoproducts.  expansions  solution  this  Crystals  mixture  to  the  for  5%  of this  yield).  is  the  substitution pattern  i t s conviction.  the assignment are presented  was c o n f i r m e d b y a n X - r a y  This  The  NMR  and  encounter  therefore  spectrum  i n PART I I o f t h i s  crystal analysis  first  ( F i g u r e 2.10).  required  along with  thesis.  The  with  details  structure  lIlL ~!  i  i  i  I  1  1  I  i  1—I—r-r  '  1  '  I  I  I  I  I  '  i  I  I  I  4  I  [  I  I  3  ppm  43f  43d 43f  /  43e  43f  . -i ï'«  Figure  I  43  43  __JA.  I  4.05  Photolysis  NMR  rr s.'*  Spectral  of Benzobarrelene  3^  Expansions 43  ' s'o'  of  i n the S o l i d  - i ~ — — ^ 1  the State.  Reaction  Mixture  ppm  from  —  I  The s e c o n d c h r o m a t o g r a p h i c The  third  band  was  band  was  rechromatographed  1,2-disubstituted benzosemibullvalenes were in  characterized  Figure  the  together.  2.05 a n d d e t a i l s  The  of this  recovered  t o give an i n s e p a r a b l e mixture  43d and 43e. C o n s e q u e n t l y , NMR  (Figure  43f  undergoes  4.02).  The  ratio  of  a  also exist  43f  to  ina  of two  i s shown  PART  I I of  does  ratio;  not  slower  affect  the  w i t h acetone, As  shown  thesis, come  two  initial  vinyl-vinyl  initial  bridging 43e  material  Cg^  positions  the  labels  43d  and  successive  i f  will  43e  on  (paths  compound 4 3 d ( p a t h s starting  4.01  types or  i  mentioned  benzo-vinyl side  of  throughout  (43d  and  rearrangement,  bonding. the  For  double  either  both  bond  43e)  cases,  leads  i l l ) , and b r i d g i n g on t h e e s t e r s i d e  eventually  initial  photolyses  periodically  di-7r-methane  i and i v ) . Deuterium  labels  find  benzo-vinyl  on  their  C^j^ a n d  way  bonding  to  occurs.  C4  of  to  gives the  t h e ^23. Similarly,  b e l o c a t e d i n t h e C^IQ a n d C g ^ p o s i t i o n s o f p h o t o p r o d u c t s  i f initial  vinyl-vinyl  chromatographic  to  of  i and  will  the solvent  analytical  benzosemibullvalenes  benzoyl  s p e c t r a were r u n i n b o t h used  and  initial  the  of  state  a singlet-mediated reaction.  1,2-disubstituted  from  compound  Figure  photostationary  h o w e v e r , t h e r e a c t i o n was n o t i c e d t o p r o c e e d  indicating  i n  [1,3] s h i f t i n  4 3 g i s 2 : 8. V a r y i n g  or acetone) i n a s e r i e s  was  i n  photochemical  (benzene, a c e t o n i t r i l e ,  NMR  the  spectrum o f t h i s mixture  assignment are provided  s o l u t i o n t o g i v e compound 4 3 g ; t h e y  can  material.  thesis. Benzosemibullvalene  the  starting  alleviate  an  separations CDCI3  bonding  and  route  taken.  o f the deuterated  overlapping  v i n y l - v i n y l b r i d g i n g was t h e o n l y  i s  benzene-dg; signal.  taken  reaction  the  latter  The r e s u l t s  (labels  After  show  two  mixture, solvent initial  o n C2b a n d Cg^^).  from  The  6b,ôc-disubstituted b e n z o s e m i b u l l v a l e n e 4 3 f i s s u g g e s t e d  to  an  unusual  this  reaction  to  proceed,  requires shown  route,  three v i n y l  in  bonding  Figure  (route  groups  4.06. of  a " t r i - 7 r - m e t h a n e " rearrangement;^-'-  the  s e p a r a t e d b y two m e t h a n e  Instead  of  di-;r-methane  a  bond  carbons  being  broken  rearrangement) ,  another  431  Figure  4.06  Tri-w-Methane  Rearrangement  Mechanism  after  to  come  initial bridge  O  Form  Benzosemi-  bullvalene 43f.  is  formed  biradical  to the t h i r d is  and  C4 labelled  of  the  cleaved  product  d o u b l e bond. F i n a l l y , to d i r e c t l y  bond  give the observed  b e n z o b a r r e l e n e 43 r e a r r a n g e d t o t h e supporting  this  c  of  this  product and  polycyclic  ( 4 3 f ) . The C]^ C^j^ p o s i t i o n s  t r i - 7 r - m e t h a n e mechanism. However,  there  is  still  (path  u n c e r t a i n t y as  i ,  Figure  bonds form  at  4.06), or b e n z o - v i n y l  the  t h a t such process The the  same  time  that  solid no  Recall  that  the  second  step  bond-cleavage  secondary If  a  this  first  adjacent  bond  cleavage  loses  this  product held  radical should  that  step  be  has  be  rationale  the  crystal  were  and  1,2-disubstituted  are  seen  starting  material  both  calculated  itself.-'-''  Interesting  to  from are  2a,6c-disubstituted in  approaches are  the  forwarded  As  (BR2  and  aligned  (BR2)  the  two  4.07). the  by d e l o c a l i z a t i o n , after  the  the  the  second  system  that  2a,6c-disubstituted i f  delocalization and  the  stabilize  than  However,  of Figure  to  (BRI)  result,  favored. then  BR3,  delocalization  a  the  of  carbonyl the  1,2-disubstituted  several  short-falls;  i f  out  conjugation,  both  of  regioisomers solid  here.  stability  is  adjacent product  BR3.  has  shows  relative  stable  possible  indeed  42  products  Two  intermediate  more  be  formed, v i a  dibenzoyl  that  1,2-disubstitution  4.01).  this  (BR3),  will  not  a l s o be This  the  retains  conjugation,  will  the  the  initial  will  BR2  of  very  pathways  conformationally  the  delocalization  out  likelihood  Zimmerman  are  vinyl-vinyl  benzosemibullvalenes  intermediates  is  of  system  from  as  is  observation.  group  radical  the  from (Figure  1,3-biradical  then  i i ) . The  results  reaction  approach r e l a t e s to  carbonyl  formation  2a,6c-disubstituted  differ  The  (path  small,  state  benzosemibullvalenes  to r a t i o n a l i z e  is  bond  i s energetically disfavored for barrelene  observed  fact  formed.  to whether i n i t i a l  state  should results.  Furthermore, the  benzoyl  X-ray carbonyl  be  the  carbonyls  2a,6c-disubstituted  formed, Only  crystal  in  similar  to  1,2-disubstitution analysis  of  i s non-conjugated with  the the  vinyl  group but  the  This  analysis  would  initial 43a  benzoyl  from  initial in  dibenzoyl  system  4.07  semibullvalene  predict  side bridging  plausible  Figure  ester i s nicely  the  the and  aligned for conjugation formation the  (42),  Radical  I t i s not  formation  the  solid  supportive  of the  Stabilization  F o r m a t i o n i n the  Solid  to  of  from  2a,5c-disubstituted first  state  approach results  observation  seemed of  the  here.  Approach to 1,2-Disubstituted State.  4.08).  o f 1 , 2 - d i s u b s t i t u t e d 43d  ester side bridging. Although this rationalization  (Figure  Benzo-  Flgure  4.08  Conformation  The  X-ray  Crystal  Structure  of Benzobarrelene  second  approach  the  substrate  proceeds  with  to  the  rationalizing  geometry  Such changes t h a t conform those  of  Figure  shows,  for  4.09  with  the  two  geometric  on  the  initial  changes  benzo-plane  First,  with fixed  associated  with  to  the  the  formation of  interactions  changes  to  product,  w i t h i n the  will  be  pathways  must  models,  be  the  bridging. motion,  f o r reference.  key  appendages,  as  bond-making  and  and  and  geometric  understood. required  43h  (2a,6c-  I n o r d e r to emphasize  the  The  lattice.  motions  (1,2-disubstituted)  the  allowed  the d i f f e r e n c e s between the  molecular  1,2-  a unimolecular reaction  environment  ester-side  t h e movements o f t h e l a r g e c a r b o n y l  As  Intermediate(s)  molecular 43d  sole  i s from s p e c i f i c  species  reaction  based  from  through the  the  lattice.  to the l a t t i c e  t h e f o r m a t i o n o f compounds  disubstituted), the  of  t h a t do n o t , d i s a l l o w e d .  requirements  state  crystal  from s t a r t i n g m a t e r i a l  three-dimensional  Displaying  43.  over 2 a , 6 c - d i s u b s t i t u t i o n i n the s o l i d of  Stereodlagram  models  are  drawn  items to watch f o r are they  bond-breaking  are  intimately  portion  of  the  Figure  4.09  Motions  Required  for  Benzosemibullvalenes  43d  and  43h  Formation.  molecule.  These  interferences.  appendages  Cleavage  of  are bond  most b  to  likely form  to  suffer  compound  43d  from  lattice  causes  a  slight  shift  of  both  ester  Cleavage o f bond a to g i v e frontal  downward  compound  sweeping  out  of  favored  solution  a  large  r e q u i r e s more movement t h a n one  must  be  aware  next  starting the using from  the  there  is  motion  upward  F i g u r e 4.10.  the These  examine  a  fixed  above  intermolecular outward  benzo-plane; interactions  the  benzoyl  In  This  i n t e r a c t i o n prevents  f r o m m o v i n g upward and oxygen  motions  the  which  of  lattice hinder  reference  benzo r i n g  the  association  of  are  shown  with  suggested  to  assist  3.60  the  two  carbonyl  deter  and  t h e c a r b o n y l c a r b o n on  2.82  The  with  lines  the  state.  benzoyl  contact  phenyl  group.  oxygen o f the b e n z o y l  the  On  the  e s t e r are  molecule,  der Waals r a d i i  in  formation  o x y g e n i s i n v o l v e d i n a n H-•-Q  of a neighboring  clearly  appendages dotted  i n the s o l i d  Â,  limiting i t s  that would  with  the  supported;  than  found the  of or  is  below  movement  of van  as  representation  less  the o r t h o - p r o t o n  sum  to  However,  exaggerated,  distances  h y d r o g e n o f an a d j a c e n t  respectively.  be  the  o u t w a r d t o f o r m compound 43a.  and  may  may  of  are  are  counterpart.  crystal  p r o x i m i t y t o an a r o m a t i c Â,  the  products)  contacts  these  carbonyl  Â)-*-^^ w i t h t h e o r t h o - p r o t o n  ether  in  (2a,6c-disubstituted  point  and  reaction.  and  space.  validity  (2.70  the  benzoyl  left.  considered.  of 2a,6c-disubstituted benzosemibullvalenes First  the  formation  contacts  intermolecular  during  inhibit  are not  The  contacts  four  to  the  to  Clearly,  described  close  as  of  appendages,  respect  for  ring  many  the  to  of  1,2-disubstituted  the  motions.  table  are  allowed  step  benzo  the  groups  maintains  volume  its  that  material  required  43h  products  t h e movements o f t h e b e n z o - r i n g The  benzoyl  p o s i t i o n b u t p i v o t s t h e e s t e r t r e m e n d o u s l y u p w a r d and  the r i g h t , the  and  at  group  other  side,  i n very  close  2.78  f o r H-•-0   i s 2.72  and   and  for  contacts  C---H  is  restricts  2.90  Â.'"  the  upward  and  of  compounds 4 3 d a n d 43e becomes c o m p e t i t i v e l y f a v o r a b l e . significant,  the  these  r e q u i r e d f o r the  formation  better  result,  movements  of  compound  are very  a  outward  influence  of  distances  As  directional  formation  described  43h.  The  less  motion-demanding  as t h e c l o s e r  the  These  contact,  the  the c o n t r o l i n s e l e c t i v i t y .  Figure  4,10  barrelene  Packing  Stereodlagram  rearrangement i n t h i s  state, formation  Benzoyl  Methyl  Ester  Benzo-  43.  Benzosemibullvalene  have ever  for  43f i s the f i r s t  study.  In fact,  very  been o b s e r v e d . P h o t o p r o d u c t thus  some  specific  of this product.  Recall,  lattice the  observation  of  a  few t r i - 7 r - m e t h a n e  43f i s formed o n l y effect  must  substituted  be  vinyl  tri-jr-methane rearrangements in  the  enhancing on  the  solid the ester  side  is  required  to  ( F i g u r e 4.06). Upon the  ester  carbonyl  for  C---H  to  examination carbon  an a d j a c e n t m o l e c u l e . radii  bond  This  distance  is is of  the benzo-ring of  the  2.82  interaction  could,  required f o r benzo-vinyl tri-TT-methane  product  well 2.90  43f  observed.  in side  the and  intermolecular  the  sum  Â.''^  The  directionality  move  lower  resulting solid  toward the in  of  van  the  der  the  the  Waals  of  benzo  activation formation  state. A similar  therefore,  contacts,  an aromatic hydrogen o f  below  to  turn,  bridging,  not p r e s e n t on t h e b e n z o y l is not  in  above   away f r o m  i n t e r a c t i o n encourages the e s t e r group This  i n t h e d e s c r i b e d mechanism  this ring.  parameters of  the  interaction i s  reciprocal  product  B.  Photochemistry  of  Ethyl  2-Benzoyl-l,4-dihydro-l,4-ethenonaphthalene-  3-carboxylate (44).  The s i m p l e r e p l a c e m e n t was  done  different  to  study  molecule.  investigated,  the  the  of  effect  Before  methyl  of  the  solution  a  the solid  Figure  first  4.11  (Figure  crystal phase  photochemistry  dihydro-1,4-ethenonaphthalene-3-carboxylate understood  group  with  an  lattice  ethyl on a  selectivity of  (44)  ethyl must  group  slightly can  be  2-benzoyl-1,4be  thoroughly  4.11).  Photochemistry  naphthalene-3-carboxylate (44).  of  Ethyl  2-Benzoyl-1,4-dihydro-1,4-etheno-  Similar acetonitrile of  to the led  methyl  to  two  s o l v e n t . These were  44b,  44c,  b y NMR from  44d,  m a j o r and  later  44e,  and  ( F i g u r e 4 . 1 1 ) . On column  analog,  direct  in a ratio  a preparative  chromatography.  The  in  by  NMR  o f 45  scale  first  to : 32  be : 10  three  : 10  bands  were  (44b), r e s p e c t i v e l y .  correlated  b a n d was  a 1  44e;  Again,  to  : 7  the  their  patterns  molar  latter  two  assignments  excess  g a v e two  of  two b a n d s w e r e e t h y l  52  48  for  characterization. The  of to of be  was 44b  g i v e the :  is  GC.  PART I I f o r t h e i r  photolysis  2a-benzoyl-  these  and  compounds  assignment.  8  [1,3]  benzosemibullvalenes  44a  and  from  by  NMR.  from  44c  of  the  interconversion  two. is  product  photostationary  and  was,  [1,3]-photochemical  C2a-Cgp b o n d . T h i s i s l i k e l y  in  a  Benzosemibullvalene therefore,  shifts  photolyzes  a  process  ratio  44c The  and ratio  independent (A > 290 state  nm) ratio  44f, however, c o u l d not  characterized  initiate  a singlet  in  column chromatography  44a  44f  radiation)  benzosemibullvalenes  photolyses  This  using  benzosemibullvalene  : 4 4 f b y NMR. 44a  isolated  between  :  shift  80-fold  of i n c i d e n t  independent  44d,  an  92%  state  44c,  data.  ca.  (absorbs  third  mixture.  44  from 2  of  The  this  compound  Compound 44c was  Likewise,  1 = 44a  separated  These  by  confirmed  solvent.  9  isolated  (44a)  compounds w e r e c h a r a c t e r i z e d f r o m  photostationary  t o 44c  spectral patterns of  w e r e b a s e d on NMR  major products, :  The in  benzophenone  of  of  : trace  were  : 2 inseparable mixture of benzosemibullvalenes  Triplet-sensitized  44b  : 3  44a,  6c-benzoyl-2b,6b-dihydrobenzo[a]cyclopropa[cd]pentalene-l(2aH)-  carboxylate  and  or  independent  compounds  2b,6b-dihydrobenzo[a]cyclopropa[cd]pentalene-6c-carboxylate ethyl  benzene  four minor photoproducts,  identified  44f  photolyses  through  the  as p r o d u c t s  in  a  mixture.  cleavage are  not  of  the  formed  from as  t h e benzophenone s e n s i t i z a t i o n  a sensitizer  (A > 330 run); a l s o ,  (A > 290 nm) s l o w s t h e r e a c t i o n .  B e n z o s e m i b u l l v a l e n e s 44a, 44c, 44d, and di-TT-methane  the  initial  rearrangement  vinyl-vinyl  cleavage  of  o f b o n d b. followed  bond  a;  44e  similarly,  vinyl-vinyl of  c l e a v a g e o f bond b g i v e s  preferences (path  to  4.01). side  cleavage  Similar  (Figure  bond  compound bridging a  on  gives  the ester  ester  (path  4 4 a comes  of from  i ) followed  comes  by  from t h e cleavage  the ester  compound  side  (path  side  44c,  (path  i )  alternatively,  initial  i ) and  t h e same  bonding  the benzoyl  from  quantum  o f compounds 4 4 a a n d 4 4 c , 0.072  side yield  ( s t d . dev.=  ( s t d . dev.= 0.015), r e s p e c t i v e l y .  compound 44a  compound 44c  0.2  0.2  4> = 0.072 ( std. dev. = 0.004 )  0.1  O 0.1  X  0  1  2  3  4  5  6  % conversion  and  Compound  counterpart,  i i ) were d e t e r m i n e d t o be e s s e n t i a l l y  measurements f o r t h e f o r m a t i o n  Figure  are a l l products  compound 4 4 d .  i t s methyl  between  0.004) a n d 0.064  44e  b r i d g i n g on the b e n z o y l  Initial by  the use o f acetone  4.12  G r a p h o f Quantum Y i e l d v e r s u s  44c i n Benzene.  <!> = 0.064 (std. dev. = 0.015)  0  1  2  3  4  5  6  % conversion  Conversion  f o r Compounds  44a  In  the  photolyzed but  (A  showed  mixture  >  no  ratio  of  In  another  (5  hours)  44e  a t c a . 46%  sign  :  8  : 23  crystals  compounds  : 15,  were 64  : 9  product  of  this  selectivity  gave  only  from  rearrangement.  ester  of  is  in  completely  vinyl-vinyl next  to  the  bonding  on  44e  longer 44c,  at 47%.  period 44d,  of  argument  this  starting  material  conjugation out  of  ester  and  observed  this,  is 44  the  44a.  side  be  On  the  will  therefore,  results  are  leave  group and  should  PART  formed.  IIIB.  X-ray  t h a t the b e n z o y l  group  will  both with  carbonyl  the  approach,  initial  allow  radical  the  favoring  radicals  seem q u i t e c o n s i s t e n t  the  the  that  hand,  give  over  approaches  shows  delocalized,  both  Two  of  in  this  other  2a,6c-di-  radicals  4.13)  side  a  discussed;  ability  Applying  Recall  product  products.  (Figure  to  case,  major  described  benzoyl  analog.  in  benzosemibullvalenes  initial  w i t h the v i n y l  carbonyl  product  the e s t e r  the  conjugation. on  the  relative  stabilize  difference  methyl  results  the  resonance  stabilization; The  a  the  this  is  observed  considers  bonding  disubstituted  44c.  the  approach  analysis  is  di-7r-methane  rationalizing  is  In  rearrangement  basis  reaction  and  : 9 o f 44a,  1,2-disubstituted  three  The  for  the  the  to  yellow  o f the  44d,  were  at a conversion of ca.  study  (44a)  groups  44c,  : 18  benzosemibullvalene  first  44  slightly  analysis  photolyzed  substituted  to  were  44a,  respectively  ratio,  feature  di-7r-methane  other  benzobarrelene  conversion.  analog  the  of  (2 h o u r s ) . NMR  crystals  interesting  methyl  of  crystals the  melting  show a s i m i l a r  state  from  of  until  formation  54  to  study,  nm)  experiment,  The solid  state  290  shows t h e  a  the  solid  initial  the  vinyl-vinyl  without compounds this  2a,6c-  resonance 44d  prediction  and as  compound  44a  is  the  major  p r o d u c t o v e r 44e f r o m b e n z o y l - s i d e  bridging,  a n d compounds 4 4 c a n d 4 4 d a r e b o t h f o r m e d f r o m e s t e r - s i d e b r i d g i n g .  Figure  4.13  Crystalline  The  alternative  steric the the are  interactions  fewer  same  described  The as  in  for  formation requires  of  the  of only  side of i n i t i a l  the  44a  with  rearrangement,  geometric  requirements  the  benzoyl  4.09. and  appendage  slight  from  substrate  44c on  methyl  requires  the  sideways  side  specific  the  crystal  lattice;  the  more  favorable  these  reactions  ester of  an of  considering  for  Formation  1,2-disubstituted a  comes  during  Figure  benzosemibullvalenes movement  approach  of  interactions  product. the  C o n f o r m a t i o n o f Compound 44 f r o m X - r a y A n a l y s i s .  b o n d i n g . The b e n z o - p l a n e  (43)  2a,6c-disubstituted  upward  initial  benzosemibullvalenes shift  compound  and  bonding, 44d  outward and the and  44e  o f t h e a p p e n d a g e s away f r o m t h e  i s assumed t o be  fixed  in  these  descrlptions  for  simplicity;  however,  w h o l e m o l e c u l e c a n move d u r i n g  reaction.  Consistent less  than  with  3.60    ring  shown i n F i g u r e  with  dotted  with  the  (2.72  is  A  of van  der  on  the  bridging  benzo-carbon  Waals  are  movement  giving  carbon  radii  beneath  the  enhanced  motion-demanding  Recall,  motions  Figure  4.09.  for  Again,  this  selectivity.  starting  appendages  the  material  are  drawn  contacts,  molecule.  The  sum  of  der  Waals  of  these  Â.^^  -phe  van  directionality  o u t w a r d movement o f t h e 4.09). solid  As  the  meta-proton  beside  and  C---H and  compound  44a  (2.92  the  Â) . is  i n the  products formation  effectively  little  hand,  outward  two  there  movement In  fact,  neighboring  benzoyl,  formation  44d  very  other  (2.86  distance assist  required  o f compound 4 4 a .  ester-side i t  compound  the  reveals of  ester  result,  upward  formation  the  a  s t a t e . On  arrangement  approach  the  of  vinyl  benzoyl  for  movement  ester-side  1,2-disubstituted  required  associated  the  i n the  the  i n t e r a c t i o n s are  and  the  on  distances  o x y g e n i s i n v o l v e d i n two  preventing  packing  intermolecular  restrict  to  the  Â)  (Figure in  kept i n mind t h a t  diagram o f the  (2.59  2.72  the upward and  the  contacts  state  is  group, r e q u i r e d  the  19  effect,  packing  adjacent  produced  of  bicyclic from  an  distance  pressing  other  solid  of  o f compound 44c  benzoyl  contacts  less  in  ester carbonyl  interactions  examination  the  Â)  44c such  the  should,  total  relevant contacts  The  inhibits  formation  compound  of  4.14;  f o r t h e 0-•-H  a r e no  o f the  reaction.  lines.  interactions for  13  ester-side bridgehead proton  proton radii  This  during  m u s t be  the model, e x a m i n a t i o n o f  shows  the benzo r i n g .  benzo is  with  i t  Â)  one  from  and  the  R e c a l l t h a t the 2.90  Â.^^  upward and relative (44d are  explains  These outward to  and  the 44e).  depicted the  sum  in  observed  F i g u r e 4.14  Packing Stereodlagram o f B e n z o b a r r e l e n e  Intermolecular  C.  44  Showing  Selected  Contacts.  P h o t o c h e m i s t r y o f I s o p r o p y l 2-Benzoyl-l,4-dihydro-1,4-ethenonaphthalene-  3-carboxylate  The solid  isopropyl  state  the use  (45).  photoreactivity  o f a more  chemistry  derivative  must  bulky be  may  was  studied  experience  side-chain  investigated  also  group.  first  with  greater Again,  to ensure  the  idea  that  lattice control  the  solution  the completeness  by  photoof  the  s tudy. Direct methanol of  photolyses  showed  two  (A  major  s o l v e n t ( F i g u r e 4.15). The  >  330  nm)  p r o d u c t s and products  in  benzene,  acetonitrile,  three minor p r o d u c t s  were  subsequently  or  independent  identified  as  Flgure  4.15  compounds 8:4,  Photochemistry  45a,  respectively  photolysis  was  isopropyl carboxylate NMR  45b, by  NMR  45d,  and  45e  integration  in of  r e p e a t e d on a l a r g e r s c a l e  Ester  a the  and  Benzobarrelene  ratio  o f 50  reaction  : 30  45.  : 8 :  mixture.  The  from column chromatography,  2a-benzoyl- 2b,6b-dihydrobenzo[a]cyclopropa[cd]pentalene-6c(45a)  analysis  established  45c,  of Benzoyl Isopropyl  was  agrees in  PART  isolated with II.  the The  in  the f i r s t  typical second  band f o r c h a r a c t e r i z a t i o n .  pattern band  for  these  contained a 7  structures,  : 3 mixture  of  compounds 4 5 b a n d 4 5 c ; t r a i l i n g 45e  i n another  3 7 - f o l d molar excess  compound  photolysis  This  photoproduct. 45a  (A  o f benzophenone as  radiation).  a secondary  band  were  eluted  is  to  >  330  prevent  the  second  a 3  :  The  structures  by  band  of  mixture  both  benzosemibullvalenes Photolyses  of  (45c)  compounds  compounds  45d  column  and  benzosemibullvalene  4 5 c ) , independent  of  chromatography,  solvent.  by  a  i n this  [1,3] s h i f t  excited  state  benzophenone from to  The  (A  acetone two  initial  suggested, 69  45e  were  the  to  a >  as  290  nm)  bands;  isolated  (9%  easily  i n  yield). assigned  1,2-disubstituted  thesis. i n benzene, of  acetonitrile,  87%  (  9  :  1  =  4 5 c was i n s e p a r a b l e  isopropyl  6c-benzoyl-2b,6b-  two  compounds  is  and  no  are  was  interconverted  interconversion  singlet with  the r a t e o f r e a c t i o n i s slowed  state  performed  (45b)  o f t h e C2a-Cg^ bond. A  Benzosemibullvalene  were  of  The r e m a i n i n g  there  photostationary  93%  three  45e  other  conversion  cleavage  kcal/mole)^^  photolysis. in  photolyses or  is (Ej- =  acetone exist  from  These  a  The t h i r d b a n d was  and  45c  therefore,  mixture.  ca.  was  dihydrobenzo[a]cyclopropa[cd]pentalene-1(2aH)-carboxylate characterized  and  6c-benzoyl-2b,6b-  45d  d e s c r i b e d i n PART I I o f t h i s  of  done  gave  (37% y i e l d ) .  o r a c e t o n e g a v e compound 4 5 b t o a maximum  by  using  Isopropyl  c o m p a r i s o n w i t h t h e NMR a n d I R s p e c t r a o f  :  was  (absorbs  separation  (47% y i e l d ) .  f o r characterization  inseparable  45b  45d  t h e f o r m a t i o n o f compound 4 5 b ,  Chromatographic first  nm)  sensitizer  benzo[a]cyclopropa[cd]pentalene-2a-carboxylate  1  compounds  mixture.  Triplet-sensitized  incident  the second  45a with  in  was  also  compound  benzene,  found  4 5 f . The  acetonitrile,  a f f o r d a 9 : 1 r a t i o o f 45a t o 4 5 f i n d e p e n d e n t o f s o l v e n t .  compounds  are  also  inseparable  by  column  chromatography;  as  a  result,  isopropyl  1-benzoyl-2b,6b-dihydrobenzo[a]cyclopropa[cd]-  pentalene-6c(2aH)-carboxylate mixture.  T h e s e two  photochemical  [1,3]  (45f)  was  characterized  to  the  benzoyl  cleavage come  above.  45d. 45d  initial  Initial and  45e  compounds  t h e same r e a s o n i n g a s  energetically  (std.  both  come  can  be  from  Similarly,  of bond a g i v e s  45c  this  -  bonding  This  to  and  (Figure  4.16).  bonding,  w h e t h e r i t i s on t h e  45a  and  d e s c r i b e d . Benzosemi-  vinyl-vinyl  0.071  benzoyl  give  on  and bond b and  45d  dev.  preference  bond  studies  of  values  (path  the  analogous is for  to  0.006), in  yields  bonding  determined =  b  benzosemibullvalenes  yield  were  side  bonding  45c  of  benzo-vinyl  Quantum  (std. no  cleavage  deuterium  45c  the  the e s t e r s i d e (path i ) ; the  also  initial  occur.  indicates  the e s t e r s i d e (path i ) .  can  showed  compounds 0.007)  and  4.01,  g i v e s compound 4 5 a  on  i v ) . However,  thesis  Figure  benzosemibullvalenes bonding  i i i and  in  easily  initial  vinyl-vinyl  unfavorable  of  dev.  formation  benzo-vinyl  (paths in  formation  45e  45e.  r e s u l t i n g cleavage  the  s h i f t b a s e d on  s i d e (path i i ) ; bond a cleavage  gives  from  and  from  a singlet-mediated  photoproduct  b u l l v a l e n e s 45a  NMR  compounds a r e a l s o i n t e r c o n v e r t e d b y  R e f e r r i n g t o the di-ir-methane pathways l i s t e d routes  by  be  too the 0.072  respectively  side  i i . Figure  of  initial  4.01)  or  compound 45c  compound 45a 0.2  0.2  4> = 0.072 ( std. dev. = 0.007 )  ^ = 0.071  0.1  ( std. dev. = 0.006 )  0.1  X——JT  x  0  1  2  3  4  5  6  0  1  % conversion  Figure and  4.16  Graph  photolyzed  (A  solid >  s a m p l e was a n a l y z e d  conversions  290 nm by  study, and A  NMR.  Conversion  f o r Compounds 4 5 a  crystals >  Three  of  330 nm)  compounds  Benzobarrelene  45  and the r e s u l t i n g were  detected,  o f 10 : 45 : 45 a t c a . 3 2 % c o n v e r s i o n .  ( c a . 73%) c a u s e s s u r f a c e m e l t i n g ;  i s interesting  crystalline formation  the  Quantum Y i e l d v e r s u s  this  were  unmelted  45a,  45d,  Photolyses t o  i s accompanied  a n i n c r e a s e i n compound 4 5 a f o r m a t i o n . It  in  3  % conversion  state  45e w i t h a r a t i o  higher by  2  45c i n Benzene.  In the  and  of  X X  the  phase of  solid  same  advanced  state.  and  specifically  reaction  see again  stems  I n an  approaches, critically from  the degree  here  selectivity  1,2-disubstituted  two  approach  to  compared  to  benzosemibullvalenes  effort used  to explain i n PART  discussed.  conjugation  that  differencei n solution.  i s highly  the observed  I V - A a n d PART  Recall  conformational of  the large  that  electronic  favored results,  IV-B, the  effects,  the carbonyl  The  has  are  first more to the  a,/9-unsaturation. can  efficiently  As  a  (45d  bond  4.01),  (45a  and b  cleavage  4.17  a  carbonyl an of  giving  45c).  and 45e) as w e l l  Figure  the  stabilize  result,  (Figure  bond  If  the  radical  first  to  the by  intermediate  2a,6c-disubstituted  form  as t h e i r  Crystalline  co-planar  adjacent  Carbonyls to  is  out  of  vinyl  then i t  delocalization. will  be  cleaved  benzosemibullvalenes  conjugation  1,2-disubstituted  should  give  benzosemibullvalenes  2a,6c-disubstituted counterparts.  Conformation  of  Benzobarrelene  45 f r o m  X-ray  Analysis.  The in vinyl  Figure  crystalline 4.17.  and the b e n z o y l  The  conformation ester  carbonyl  is  of  carbonyl almost  benzobarrelene is  in  completely  45  conjugation out  of  is with  shown the  conjugation  with  the  vinyl.  disubstituted  As  a  result,  product  (45a)  1,2-disubstituted  product  somewhat show t h i s  trend;  of  cleavage  competitor  formed.  However,  isomer  opposite  to the p r e d i c t i o n .  its  The  alternative  each r e a c t i o n path crystal fixed,  lattice  and  contacts  o f the b u l k y  relatively  few  are  associated  the  benzo  largest the  shown  in  side  of  on  other  the the  opposing  formed  and  compounds four  to  these  from  required  X-ray  the  side-chain  this  the  than  two  reason  requires    i t  movement  large  side to i n i t i a l  counterpart.  formation  are  and as  45e much  with the  of  of  bonding. This  much  both  as  45a,  of  specific  benzo-plane 4.08.  In  lattice  fact,  a l l and  25  the  and These  table  only  ring  of  2  involve  to  model  observe  motions  motions  1,2-dlsubstituted the  and  interactions  away  2a,6c-disubstituted  upward  are  Figure  crystal  fixed  of  do  observation  realistic  (benzo-ring).  Formation a  more  the  s t r u c t u r e r e v e a l s many  the  i n d i c a t e s t h a t the m o t i o n r e q u i r e m e n t s f o r  semibullvalene  no  Holding  shows  is  and  g e o m e t r i c demands  appendages  formation  sideways  bonding.  3.60  groups)  region The  45a  benzo-ring.  carbonyl  (carbonyl  4.18.  with  motions  data.  2a,6c-  observed r e s u l t s  appendages are m o d e l l e d i n  with  less  The  examine the  the  4.01)  times  to  slight  hand,  is  isopropyl  largest  initial  45d  in this  region  Figure  i i .  formed  favor  (Figure  of the c r y s t a l packing  For  next  would  path  is  correlate  with  requires only a  still  is  approach  associated  ring.  i  from  45c,  45e  approach  path  compound  intermolecular distances  on  (45d)  t h e movements o f t h e b u l k y examination  of  from  interactions  However,  the  this  twist  of  the  simple  change o f  are  products from  the  products, benzo-ring reference  1,2-disubstituted  benzo-  l e s s than f o r i t s 2 a , 6 c - d i s u b s t i t u t e d  -1A2-  Figure  4.18  Motions  Required  the Carbonyl S u b s t i t u e n t s  i n Relevant  Fixed.  Di-jr-Methane  Pathways,  Holding  Examination ring  shows no  represents  of  t h e b e l o w 3.60  significant  a CHO    c l o s e c o n t a c t s . The  h y d r o g e n b o n d (2.37  the of be  group  benzo-ring. the  two  3.64  Waals  radii  twisting formation  not  shift  adjacent  dotted   from the  for  the  of  these  motion  45a  groups  benzo-ring  This  approach and  and  product  the  compounds 45d  distance  o f the b e n z o - r i n g  (compounds  45e.  are  benzo-plane.  methyl  will  On  formation  nicely  line two  the  Recall  Figure  neighboring 4.19  the  benzoyl  the  other  isopropyl the  the above  positions  by X - r a y a n a l y s i s t o  3.70  (compounds  rationalizes  4.19  shows  relative  clearly  the  benzo-  positioned directly  measured  is  of  sum  kJ^  of The  impede  van  the  hand, 45d group,  product  45e)  favoring  observed  and  upward  the  and  der  location  required i n 2a,6c-disubstituted  45c).  towards  is  illustrate  methyls  CH3 • • • C  solid  diagram i n Figure  molecule  lines  the  4.51  1,2-disubstituted  formation. for  The  an  components   and  distances  to  of  i n t e r a c t i o n s to the  Â) b e t w e e n t h e  groups. F u r t h e r a n a l y s i s o f the p a c k i n g isopropyl  lattice  route will its  selectivity  F i g u r e 4.19 Two  Different  X-ray  P a c k i n g Arrangement of Benzobarrelene  Faces.  45  Shown  f  The  table  in  PART o f t h e t h e s i s . substrates  i s very  semibullvalenes controlling  Figure  The  solution  similar.  greatly  over  selectivity  electronic  stabilizing  in  III  PART  of  4.20 s u m m a r i z e s t h e r e s u l t s  are  A l l favor the  the  provided  thesis.  E  behavior  From  with by  B  the  the  the  the  products.  three  Factors  rationale  based  carbonyls,  determined  B  of  i n this  2 a , 6 c - d i s u b s t i t u t e d benzo-  1,2-dLsubstituted  consistent  effect  the  photochemical  gathered  on  suggested  quantum  yields,  E B  I' A initial benzoyl-side bridging  Starting Material compound #  43a  (43c)*  T I  initial ester-side bridging  43h  initial ester-side bridging  (43b)*  initial benzoyl-side bridging  43d  43e  43f  12 50  12 30  0 20  43 E= COgMe B = benzoyl  s o l u t i o n (%) 34 s o l i d s t a t e (%) 0 (17% c o n v e r s i o n )  compound #  44a  42 0  (44f)*  44c  (44b)*  44d  44e  44 E = COgEt B = benzoyl  s o l u t i o n (%) 45 s o l i d s t a t e (%) 54 (47% c o n v e r s i o n )  compound #  45a  42 8  (45f)*  10 23  45c ( 4 5 b ) *  45d  3 15  45e  45 E= C02iPr B = benzoyl  s o l u t i o n (%) 50 s o l i d s t a t e (%) 10 (32% c o n v e r s i o n )  38 0 *  4 45  45  the [1,3] shift product is included in this value. Tri-Jt-methane product.  F i g u r e 4.20  Table Summarizing S o l u t i o n  in the Photochemistry  and  Solid  o f Compounds 4 3 , 4 4 , a n d 4 5 .  State  Product  Ratios  products  from  initial  ester  side  bridging  and  initial  benzoyl  side  b r i d g i n g a r e f o r m e d a t a b o u t t h e same r a t e . With of  the  ethyl,  respect  thesis,  to  the  i t is  three  interesting  and i s o p r o p y l d e r i v a t i v e s ,  conformation.  Consequently,  bore  consistency  interaction three  the  dominant  also  with  approach  is  observe  this  that a l l three,  substrates  should  observed;  only  model.  explained  in  the  same  On  the  the  show the  other  results  quite  methyl,  electronic  similar ethyl  hand,  PART  crystalline  approach u s i n g conformational  not  the  interesting  in  product  have  is  to  studies  product  derivative  the  lattice  effectively  in  a l l  cases. It  state  This  state  possess b a s i c a l l y  e f f e c t s p r e d i c t s that a l l three distributions.  solid  solution  determination selectivity.  had  recent  found  to  to  specific  Further  dibenzobarrelenes.  in  that  chemistry,  to  literature this  see  this  electronic play  lattice matter,  precedence. a  study  of  a  effects,  secondary  interactions such  Scheffer,  direct Trotter  unsymmetrically  though role  in  in solid  comparisons et  al.-'-^'''  substituted  PART V.  PHOTOCHEMISTRY OF BENZOBARRELENE  The thesis  three  substrates  studied  different  lattice  a l l possess  X-ray  analysis.  required  Lattice  reaction  governing  i n  the  was  previous  environments  interactions  geometry  reaction  SALTS  i n  determined  to  be  between  the  2a,6c-disubstituted  di-7r-methane  products  i n  Examination  geometric  (Figures  the  4.09  and  benzosemibullvalene its  4.18)  Cohen,^2  minimal from  the  i n  i n  of  a  benzosemibullvalenes  should  2a,6c-disubstituted  competitor.  to  support  to  achieve  tedious The  diacid NMR, these  of a  IR,  and  this,  routes  logical  with  Introduction,  and  In  order  i t would  be  crystal and  factor  by an  choice.  state.  f o r formation the  original  those  concept  reactions  much  to  than  with  interference  Therefore,  the  1,2-disubstituted  to  i t s motion  demanding  to  accumulate  evidence  ideal  to  design  arrangements  complicated  simply amine  or  carbon-hydrogen  compounds.  These  compounds,  refluxing metal  a  while  separations  Conveniently,  most  shown  in  stoichiometric  hydroxide.  analyses  were of  and  two r e g i o i s o m e r s  vice-versa.  than  the  2a,6c-disubstituted  without  rearrangement greater  with  of  method avoiding isomers.  1,4-dihydro-1,4-ethenonaphthalene-2,3-dicarboxylic  prepared 40  be  different  synthetic  seem be  refute  many  salts  (40) can  or  on  lattice  di-jr-methane  the  Reflecting  proceed  from  solid  f o r these  that  this  shown  major  the  motion  will  the  of  1,2-disubstituted  greater  the  geometry  surrounding  likelihood  much  counterpart.  discussed  changes  reveals  requires  1,2-disubstituted  by  requirements  as  association  selectivity  of  part  Standard used these  acid  F i g u r e 5.01, amounts  of  methods such as  to  characterize  compounds  are  crystalline state  with  high  melting  photochemistry  completeness  of  must  the  temperatures.  be  study  .  Again,  investigated  Photoproduct  the  first  to  solution ensure  characterization  is  the  easily  a c c o m p l i s h e d by c o n v e r s i o n t o t h e i r c o r r e s p o n d i n g a c i d s f o r r e f e r e n c e . Recall  that  in  the  direct  solution  ( F i g u r e 3.08),  the  singlet-mediated  is  the  only  formed  formed  as  only  from  photolyze ratio  general them  of  in  corresponding state  procedure a  is  suitable  diacids  ratios  reaction mixture.  by  easily  s t u d i e s were c a r r i e d  photoproduct  of  cycloaddition  t r i p l e t products  Crystalline  diacid  product  40  (40c)  ( 4 0 a and 40b) a r e  compound  40  gives  no  photolysis.  photoproducts  characterization  and  sensitization.  d e t e c t a b l e p r o d u c t s from The  product  [2+2]  photolysis  were  for out  used  in  solvent NMR  the and  reference.  by In  nitrogen  determined  by  NMR  of  analyze  signal  accomplished  in  study  a  the  s a l t s was t o  the  corresponding  integration.  Photoproduct  conversion similar  filled  NMR  analysis  to  fashion, tubes  and  their solid the  of the dissolved  F i g u r e 5.01  Photochemistry o f Benzobarrelene  The s o l u t i o n ratios  of  results  are l i s t e d  cyclooctatetraene  b u l l v a l e n e 40b  salts.  conversion  order  in  The to  i n F i g u r e 5.02  of  direct  diacid  40.  photolysis  photolyses minimize  of  t o show t h e  40c, b e n z o s e m i b u l l v a l e n e 40a, and were  the  carried  formation  I t was n o t i c e d t h a t a g r e a t e r p r o p o r t i o n o f from  Salts.  amine  out  o f secondary  triplet  to  benzosemiincomplete  photoproducts.  products  s a l t s than from  relative  direct  are  formed  photolysis  Compound A8  % 1.2-sub  54 (35) 63 56  36 (55) 30 53  10 (10) 7 11  0 (0) 0 0  43 (19) 64  47 (70) 31  10 (11) 5  0 (0) 0  37 (15) 62  53 (70) 31  10 (15) 7  0 (0) 0  DMSO-dg (extracted) DMSO-dg  69 (61) 40  8 (8) 9  20 (27) 45  3 (4) 6  D2O  83 (87) 72  11 (11) 28  0 (0) 0  2 (2) 0  81 (79) 58  19 (21) 42  0 (0) 0  0 (0) 0  15 (9) 79  61 (83) 7  22 (8) 14  2 (0) 0  Solvent CDCI3  (extracted) 2 3  CDCI3 CDCI3  1  CDCI3  (extracted) 2 50  CDCI3  1  CDCI3  (extracted) 2 51  1 2  52  CDCI3  1  (extracted) 2 53  D2O  1  D2O  (extracted) 2 54  D2O  1  CDCI3  (extracted) 2  Figure  5.02  0  % COT  Trial 1  49  0  % starting material  CDCI3  Photoproduct  Ratios  % 2a.6c  from t h e S o l u t i o n Phase P h o t o c h e m i s t r y  of Benzobarrelene S a l t s .  It  has  been  capacity  to  resonance  carbonyls  of  carboxylic  more  involved  in  reported  that  carbonyls  stabilize acids.9^  an This  delocalization  of  of  salts  adjacent i s because the  existing  have  radical the  a  lesser  than  carbonyls  negative  the are  charge.  An  example  of  this  with  a c i d / e s t e r 66.^^  the  formation  of  does n o t p l a c e The should,  5.02)  66b,  the  the  of  the  product  to  sodium  from  resonance  is  a  shown i n F i g u r e  salt  of  product  formation  The  ratio  of  relative to  increases  pathway  an  to  t h a n t h a t o f t h e d i a c i d ( 4 : 6 ) . The t a b l e  radical  thesis,  increase  2a,6c-disubstituted  of  should  results  (Figure  shows t h a t s e l e c t i v i t y b e t w e e n t h e two t r i p l e t p r o d u c t s i s c o n s i s t e n t t h e model by f a v o r i n g t h e 1 , 2 - d i s u b s t i t u t e d  the  2a,6c-disubstituted  benzosemibullvalene  benzosemibullvalene  I n an e f f o r t direct  t o r e d u c e t h e amount o f  photolysis,  mono-salt  benzoyl  analog  could  triplet  energy  to  be  the  54  was  selectively barrelene  Large m e t a l c a t i o n s have assist  In l i g h t  in  intersystem  excited  reactant.  strong  crossing  o f t h i s , heavy metal s a l t s  crystallized  f o r photolysis;  facilitating  that  intersystem  In order mixture  was  the  to  large  metal  re-acidified,  the  the  from  the idea that a  internally  coupling  triplet  were  product  transfer photolysis  also  cations  counter  effects  and  e x c i t e d s t a t e . •'-^^ synthesized  and  r a t i o s reveal a very low  i n comparison t o the  photoproduct  the  formed  W i t h some s u c c e s s ,  amine  salts.  used here are i n e f f e c t i v e i n  crossing to the t r i p l e t  confirm  with  and  spin-orbit  52 a n d 53  however,  product  thesis.  formation.  to  percentage o f t r i p l e t product formation shows  singlet  synthesized  (A > 330 nm) g a v e e n h a n c e d t r i p l e t p r o d u c t  over  i n a l l c a s e s . These r e s u l t s ,  i n t u r n , f u r t h e r s u p p o r t t h e p r o p o s e d r a t i o n a l i n PART I I I o f t h i s  This  that  adjacent  2a,6c-disubstitution  with  can  3.12  of the s a l t .  stabilize  1,2-  66  di-7r-methane  r a t i o n a l f o r w a r d e d i n PART I I I o f t h i s  formation.  greater  photochemistry  Photolysis  reduced a b i l i t y  1,2-disubstituted  be  in  a r a d i c a l adjacent to the carbonyl  from  product  effect  of the substrates. assignments,  cation  the  extracted,  reaction and  the  r e s u l t i n g d i a c i d mixture product A  ratio  typical  mixture signals  by  changes v e r y l i t t l e  NMR  is  analyzed  expansion  shown  in  of  Figure  o f t h e f o u r compounds  5.03.  i n t e g r a t i o n t o e s t a b l i s h component Turning  to  c r y s t a l s o r powders pressure  mercury  the of lamp.  the s i g n a l s can e a s i l y results.  Again, be  reaction This  well  5.02  shows  mixture  region  separated  that  the  and  shows  extracted  that the proton  allowing  for  a  clear  ratios.  underlying  a l l the  Figure  from p r e - e x t r a c t i o n t o p o s t - e x t r a c t i o n .  the  are  NMR.  reason  salts the  identified  were  ratios by  for  this  photolyzed were  investigation, with  determined  comparison  with  a  medium  b y NMR  the  and  solution  a)  7*s  i.r.  7.1  s.ê  h.i  s.a  ppm  b)  aromatic  41d 4fîb  J '••s  4Û  r»  ^Ti  s's  7i  7i  71  Til  ZI  7i  71  7~,  ppm  F i g u r e 5.03  NMR a)  S p e c t r a o f t h e S a l t 48 R e a c t i o n M i x t u r e Before  Extraction.  b) A f t e r R e - a c i d i f i c a t i o n .  in  CDCI3:  1^  ©ïiCox  o c s % Compound  % 1.2-sub  %  2a.6c-sub  comment  crystal (mp = 164°C)  85 74 70  12 21 21  3 5 9  0 0 0  brown, no m e l t  49  crystal (mp = 187°C)  88 84  4 4  8 12  0 0  brown, no m e l t  67 66  20 22  13 12  0 0  brown, melted  crystal (decomp.= 90°C)  51  crystal (mp = 238°C)  88 88  10 7  0 0  2 5  brown, no m e l t  52  crystal (mp > 300°C)  87 83  12 15  1 2  0 0  brown. no m e l t  53  crystal (mp > 300°C)  73 14  27 86  0 0  0 0  brown. no m e l t  54  solid (mp = 113°C)  96 97  0 0  4 3  0 0  brown. no m e l t  F i g u r e 5.04 barrelene  Photoproduct R a t i o s from  solid  state  photoreactivity  hydrogen bonding theory o f d i a c i d  thesis. solid  the  Solid  State  Study  of  Benzo-  Salts.  The  of  % COT  ™  48  50  the  starting material  Phase  ^  Recall  that  s t a t e and t h a t  diacid  40  of  these  40 o u t l i n e d  in  salts PART  does III-B  support of  this  g i v e s no d e t e c t a b l e p h o t o p r o d u c t s i n t h e  the proposed reason f o r t h i s  the a c i d protons to the l a t t i c e  This hydrogen bonding i s reduced i n  stems from t h e  through hydrogen mono-salts  and  bonding removed  anchoring  (Figure in  3.11).  disalts;  as  a result,  reaction.  there  i s more movement a l l o w e d  Figure  r e a c t i v e i n the  5.04  solid  shows  that  the  is  finding favored  cases  that  very  demanding  its  In  with  product  formation  analysis, are over was  from  the  a  salt  only It  is  triplet  from  the state.  formation  isomer  solid  and  51  larger the  still  not is  forbidding  of  the  the  aid  In  more  amino  the  solid  singlet  [2+2]  pathway (54)  reaction. is  the  formed singlet-  s t a t e , however,  1,2-disubstituted  whether  internal  X-ray  salt  the  still  to  an  motion  is  favors  interactions  products  triplet as  of  lattice  triplet  the  from  are (54);  exclusively  sensitize  40c.  clear  behavior  2a,6c-disubstituted  the  product  is  motion  1,2-disubstituted  chromophoric  triplet  cyclooctatetraene product  select  major  motion  more  state  state  specific  amount  a l l  less  over  the  solid  The  almost  that  the  than  that to  in  3'-aminoacetophenone  forms  the  route.  internally  selectivity  lattice  s t u d i e d are a l l  benzosemibullvalene  interesting  reaction  motion  observed  for  comparison,  ( F i g u r e 5.04). W i t h o u t  photolysis, of  lattice  for  favored  however,  the  to  available  generally  (51)  imagined  relatively  this  solid  is for  salts  hypothesise^  efficiently  latter  lesser  solution  product.  most  more  o f the  designed  mediated  the  5.02);  i t  the  Although  state.  diamine  times  responsible  are  benzobarrelene  (Figure  not  Cohen's  solid  ethylene  seven  compound the  with  solution,  to  pathways  demanding ones i n the  those  is  2a,6c-disubstituted  supportive  reaction  Salts  crystal  crystalline  1,2-disubstituted  over  is  the  state.  Although c r y s t a l a n a l y s i s data the  in  the  cause  sensitization reaction  in  of or the  As  seen  thesis,  the  lattice can a  system  is  design.  in  the  solid  favor  for to  degree  system  and  other  provides  a  reactions.  reaction further  develop of  this  state  one  useful  scientists  predicting  from  benzobarrelene  effects easily  enable  cumulatively  solid  studies sensitive  Slight  pathway  over  general  state  system  selectivity  this  measure  steric  of from  of  factors  another.  structure-reactivity a  in  Such  studies  to  quantitatively a  lattice  PART  VI.  PHOTOCHEMISTRY  OF DIMETHYL 1,4-DIHYDRO-l,4,5,8-TETRAMETHYL-l.4-  ETHENONAPHTHALENE-2,3-DICARBOXYLATE (47)  The in of  recent  observation  bridgehead  substituted  tetramethyl benzobarrelene  The  replacement  other groups unusual  such  CH2CI,  favored  over  due  from  to  the  rationales  CI,  tertiary  demands  support.  this  was  In  material.  yield  the desired  of  separation;  (47a a n d  47b,  to  complete  Figure  the  i n  0.27,  products  and p e n t a l e n e - l i k e isomerization was  to  the  chosen avoid  would  to  stabilization  confidence better  being  suggested  radical  synthesized  of  this  tri-^r-methane  i n  these  understand  this  to  determine  the  1,4,5,8-tetramethyl-  1,4-dimethylnaphthalene  was  and  results  as t h e  bridgehead-substituted  i n order to increasethe a  tedious  presumably  chromatographic  add  to  dimethyl  t o g i v e a m i x t u r e o f two r e g i o i s o m e r s .  Direct photolysis of acetonitrile  this  to  study  rearrangement.  i n Figure  symmetrical  of  compound  dimethylnaphthalene  from  however,  was  synthesis  adduct  phenyl  with  effort  The  instead  This  acetylenedicarboxylate  an  this  the  dibenzobarrelenes with  rearrangement  analog  i n the Diels-Alder  starting  for  rearrangement  urged  symmetry  combined  reaction. used  or  of  centers;  t h e mono-benzo of  axes  thane  effects  some  a r e shown  reason  di-7r-me  added  naphthalene diene  the  ^ of  observed  C2  underlying  of  methyl,  Photoproducts  steric  phenomenon, generality  protons  o f dibenzobarrelenes  The  tri-7r-methane^^  47 f o r t h e p r e s e n c e  cyclooctatetraenes with  compounds.  be  as  a  dibenzobarrelenes  bridgehead  behavior.  rearrangement are  of  of  compound  47  conversion  6.01).  However,  (À  >  l e d to a  290 two  secondary  nm) major  i n benzene  or  photoproducts.  photoproduct  (47c)  from  compound  reaction  47b  behavior  were  subsequently  scale  photolysis.  Figure  6.01  is is  observed  at  independent  isolated  Photochemistry  by  higher of  conversions  solvent.  column  of Dimethyl  The  (ca. 45%). This three  compounds  chromatography from a p r e p a r a t i v e  Tetramethylbenzobarrelene  Diester  (47).  Previous were  easily  spectrum. destroys  characterized However,  the  Identification the  benzosemibullvalene  the  coupling,  by  their  signal  replacement  of  resulting  i s , therefore,  benzobarrelene  r i n g systems d e s c r i b e d i n t h i s  starting  more  in  patterns  these a  protons  series  challenging.  material  and  in  i t s  The  the  with of  NMR  thesis NMR  methyls singlets.  spectra  photoproducts  of are  shown  in  a n d NOE to  Figures  were  be  6.02  and  employed;  dimethyl  6.03.  however,  Various the  NMR  techniques  structure  of  47a  s u c h a s APT  was  confirmed  2a,2b-dihydro-1,2b,3,6-tetramethylbenzo[a]cyclopropa[cd]-  pentalene- 6b,6c-dicarboxylate  and  47b  was  confirmed  to  be  1,4,6,9-tetramethylbenzo[a]cyclooctene-5,10-dicarboxylate  dimethyl  from  X-ray  analyses. P h o t o l y s e s o f c y c l o o c t a t e t r a e n e 47b 290 nm) l e d t o c o m p l e t e i n acetone  i n benzene  conversion to benzosemibullvalene  or  acetone  (A  >  4 7 c . The r e a c t i o n  was n o t i c e d t o b e much f a s t e r . W i t h k n o w l e d g e o f  the  precursor  s t r u c t u r e a n d f a m i l i a r i t y w i t h t h e r e a c t i o n s e q u e n c e i n v o l v e d , compound 4 7 c was a s s i g n e d b y NMR  ( F i g u r e 6.03) t o  be  dimethyl  t e t r a m e t h y I b e n z o [ a ] c y c l o p r o p a [ c d ] p e n t a l e n e - 2b,  2a,6c-dihydro-l,2a,3,66b-dicarboxylate.  compound i s s u g g e s t e d  t o be a t e r t i a r y p h o t o p r o d u c t  and  photoproduct  a  secondary  probable  r e a c t i o n sequence  intramolecular This cyclobutene another Recall  photon, this  studies^^ ' 29d  is  that  [2-t-2]  cycloaddition  is  di-jr-methane  a  undergoes  the  r e a c t i o n sequence has '  of  ' •'-•'-^  as  i n PART I I I A o f t h i s  form  system,  47b  undergoes  47b. an  47 A  initial  a cyclobutene  ( F i g u r e 6.05).  and  absorption  through  of  triplet-mediated r e a c t i o n to the product. been  reported  w e l l as b e i n g o b s e r v e d thesis.  benzobarrelene  benzocyclooctatetraene  compound to  of  This  with  many  of  Bender's  with benzocyclooctatetraene  F i g u r e 6.03 in  CDCI3.  NMR  Spectra of Benzobarrelene  47 a n d  Benzosemibullvalene  47c  Triplet-sensitization benzophenone  of benzobarrelene  excess  of  region)  gave c o m p l e t e c o n v e r s i o n  approximate as  ratio  of  1  i t i s i n s e p a r a b l e by  other  unknown  shows t h e using unknown  parent  on  the  triplet  >  330  nm,  = 47a  upon  : 47d.  product  standing.  as  mixture  a  two-fold  i s transparent  o f s t a r t i n g m a t e r i a l t o two  : 1.5  mass  using  substrate  Compound 4 7 d  column chromatography  compounds  same  NMR  (A  47  47;  were  (47d)  and  however,  on  possibly  It be  decomposes  to  6.04),  di-TT-methane not  only  methyl has  expected  rearrangement.  from  the  that  secondary  due  to  internal  the  C---C  distances  Figure  apparent  steric 6.04  semibullvalenes  positions  undergo  2a,6c-disubstituted  Its  internal  substituents  found  available  the  of  the  processes. steric o f the  but with  is  the  inherent  modelling  s u b s t i t u t e n t s on  the  ( F i g u r e 6.04), i n d i c a t i n g a tremendous s t r a i n .  on  instability  ring  a  understandable pairs  research  (Figure  s t r a i n . Molecular  this  from  two  substituents ring  i t  2b,6b-dihydro-  product  Scheffer's  cyclopropyl This  of  to  6c-dicarboxylate  instability  strain  quantify  methyl  an  mixture  i s thought that  2b , 3 , 6 , 6 b - t e t r a m e t h y l b e n z o [ a ] c y c l o p r o p a [ c d ] p e n t a l e n e - 2 a , (Figure  in  unidentified  reaction  attempts  unsuccessful. may  was  the  in this  products  readily  GC-MS  molar  group-'--'-^  a l l 6.04) may  of  three readily  also  be  c a l c u l a t i o n s - ' - - ' - ^ show to  be  very  short  3.06A  E=  CO2CH3  Figure  6.04  Instability on  Proposed of  Structure  Such  for  47d  with  Benzosemibullvalenes  Analogy  Bearing  Showing  Three  Inherent  Substitutents  the Cyclopropyl Ring.  Crystalline pressure  mercury  p h a s e p h o t o l y s i s o f compound 47 u s i n g lamp o r a n i t r o g e n l a s e r  compound 4 7 a was f o r m e d a s compound  47b  at  a  ca.  the 11  %  major  (A = 337 nm)  product,  conversion.  10  Higher  :  either  a  medium  g a v e two p r o d u c t s ; 1  (by  conversions  NMR)  over  result i n  s u r f a c e m e l t i n g of the c r y s t a l . Benzosemibullvalene tri-TT-methane  47a i s s u g g e s t e d  t o come  from  r e a r r a n g e m e n t shown i n F i g u r e 6.05. R e c a l l  the  interesting  that this  product  is  analogous  to a minor  o f b e n z o b a r r e l e n e 43 from  direct,  photoproducts c a n be  triplet  t h i s product both  that  same  but  this  time  and  crystalline  i s formed  direct  The  photolysis  initial  time  as  are  highly  product  are  the  differing  sensitization, the s i n g l e t  formation, bonds  of  and  vinyl-vinyl not  likely  p o i n t e d out t h a t in  the  the  or to  energy  case  of  itself. are  several  differences  d i b e n z o c y c l o o c t a t e t r a e n e s and  the  from  products  monobenzobarrelenes  between  unsymmetrical  are  formed  This  is easily  the  subsequent  such  t h a t , b r a n c h by b r a n c h ,  are  formed.  benzo groups  rationalized; steps  Two  are  bond  The  the unsymmetrical only  selected  along  the case of the disrupted;  is  mono-benzo in  a benzosemibullvalene.  the A  the  regenerate are  same two  required system  can  the  as  there  s t e p , the r a d i c a l s bond  in  then  break  cleavage  to  6.05).  are  formed,  energy  aromaticity the  branch  pentalene-like  to  (Figure  surface  favorable intermediates  essential  biradical  Primarily,  compounds a r e  bridges  potential  t h e most e n e r g e t i c a l l y to  tri-TT-methane  correspondingly,  monobenzobarrelenes  c y c l o o c t a t e t r a e n e and bond  0.27);  tri-TT-methane  resulting  one  pentalene-like  once the  cleavages  the  dibenzobarrelenes.  (Figure  from  o f the d i b e n z o - r e a c t i o n  0.27).  and  dibenzobarrelenes  benzosemibullvalenes  ring  major  triplet  unfavorable  of  in  a  through both  has  rearrangements  contrast,  is  photolysis  phase p h o t o l y s i s  and  bridge  Zimmerman-*-^  i t  state  i n conjunction with  u n c e r t a i n . However, b o t h  f o r such processes  There  (Figure  i n the s o l i d  the r e a c t i o n proceeds  states.  is still  the  requirement barrelene  As  suggested excited  at  ( F i g u r e 4.06),  under  benzo-vinyl, form  (43f) formed  triplet-sensitized,  starting material.  it  product  to is  i n the second  step  to give both compound.  In  regain aromaticity only  one  can e a s i l y p a i r give  two  the  aromatic to  form  dibenzo-type  p r o d u c t s r e q u i r e s t o o much The  other major  octatetraene  47b,  photoproduct comes  c y c l o a d d i t i o n f o l l o w e d by reaction  is  triplet [2+2]  Figure  r e a c t i o n was  barrelene  47.  from  from a  singlet-mediated  sensitization.  6.05  energy.  No  a  thermal as  the  direct  photolysis,  benzo-vinyl ring  opening  compound  cyclooctatetraene  [2+2]  intramolecular  (Figure  is  not  from  benzocyclo-  6.05).  observed the  This under  vinyl-vinyl  detected.  Proposed  Mechanisms  to  Photoproduct  Formation from  Benzo-  Two  tri-IT-methane  for  the  The  first  process  rationales  rationale  whereby  disubstituted benzo-vinyl are  the  be  is  based  poor  over  of  the the  This  electron  of  over  compounds  47a  the  ^  An  have  ultraviolet  e x h i b i t e d no  bands  above  a tail  transfer  weak  t o 4 8 0 nm  nm.  fluorescence  r e g i o n . •'-•'-^  very  remains  400  and  Also  47b  were and  Quantiam  yields  determined  benzene  in  (Figure  was for both  6.06)  Charge - t r a n s f e r complexes  bands  above  charge-transfer  studies  b a n d s a t 335 nm,  f r o m e x c i t a t i o n a t 281 nm.  unsupported.  vinyls  400  nm.-'--'-^  concentrations complexes  can  s p e c t r a , a broad f e a t u r e l e s s band i n the  Fluorescence  emission  the  a charge-transfer  d e p e n d e n t . •'-•'•^  acetonitrile  study  to  unsubstituted  u s i n g a range o f s u b s t r a t e  UV-visible  by  donates  absorption  near  a  charge-transfer  absorption  characteristic  show  of a  characteristic  have  to  reaction.  I f indeed  to solvent p o l a r i t y .  commonly  di-7r-methane  bridging;  and  dependency  preference  group  of  no  the  possibility  benzene and a 1 : 1 m i x t u r e showed  explain  i n essence would e x p l a i n the s e l e c t e d  donors solvent  to  benzo  vinyl-vinyl  t h e r e a c t i o n may b e  formation  on  acceptor.  bridging  forwarded  rearrangement  w-electron  vinyl  extremely  involved,  a  can  were 350 nm,  The p r e s e n c e  also  conducted  367 nm,  followed  of  charge-  a  in Benzene and Acetonitrile (1:1 )  in Benzene 0.2  0.2 <t> = 0.135 ( std. dev. = 0.008 )  0 = 0.125  0)  4Zb  0.1  ( std.dev. = 0.009 ) X  4Zb  0.1  -©-  o  ^ J O  <l> = 0.11  ( std. dev. = 0.01 )  2  <ï> = 0.100  4  6  0  ( std. dev. = 0.006 )  2  4  % conversion  Figure and  6.06  Quantxim  one  of  steric  second  Y i e l d Graphs f o r the Formation o f P h o t o p r o d u c t s 4 7 a  effects  is  thought  in  this  shows  approach  t h e methods were to  intramolecularly determined  C-C  to  a  very  X-ray  This  consequence bonds,  bond  is  of  1.366(3)  1.5^  .". ;  the  selectivity  starting  f o r Cj^j^ t o Cj^g i s 2 . 9 6 3 ( 5 )  a n d C]^g t o  is  this  each  less  was f i r s t  is  A and 1.561(3)  sp^-.sp''  bo::d.s  other  benzo  (Figure  t h a n t h e sum o f t h e i r v a n d e r W a a l s  b e n t away strain  the  material  The  strain  and  approach  6.07).  against  methyls on t h e aromatic r i n g , added  product  Although  are  pushed  (3.40  ) . ^ ^  toward  this  i s  methyls  3 . 0 1 3 ( 6 ) Â. T h e s e a r e r e m a r k a b l y radii  rationale,  of  methyls  This  the dibenzo r e s u l t s .  role  analysis  and Benzene.  considerations.  i n their  large  bridgehead  distance  steric  rationalize  n o t emphasized play  the  i s from  used  situation.  that  6  % conversion  4 7 b i n Benzene and a 1:1 M i x t u r e o f A c e t o n i t r i l e  The  -o  noticed  from  the  are  even  the a n g l e s o f t h e  bridgehead  the lengthening Â. A t y p i c a l  from  of  length  shortc-r.  methyls.  An  the C^-Cg^  and the  an  sp^-sp-^  for 1,50  A. ^ ' - F r o m  molecular models, t h e t w i s t i n g o f the molecule reduces of  the s t e r i c  the resulting  strained;  only  strain product  one  on  the methyls.  ( 4 7 a ) shows  methyl-methyl  t h e m e t h y l s o n C21, a n d C 3 ( d i s t .  that  i n tri-n--methane  bridging  Crystallographic  analysis  the methyls  interaction  Intramolecular  bond  d i s t a n c e (Â)  angle  Ci-C2 C^-Cga Cx-Cg C^-Cii  1.538(3) 1.566(3) 1.530(4) 1.521(4)  C4a C 4 C4a C 5 C8 C7 C 8 a C8 C8a C l Cg Cl ^10 C 4  C3-C4  1.540(4) 1.561(3)  C4-C10  1.530(4)  C4-C16  1.531(4)  C5-Ci^7 Cg-Cis  1.501(5) 1.504(4)  F i g u r e 6.07  i s present,  Angles degir e e s  C16  Cl7 ^18 ^18  Cu  Cll C16  C r y s t a l S t r u c t u r e o f B e n z o b a r r e l e n e 47 S h o w i n g  Lengths and Angles.  between  = 3 . 1 8 7 ( 7 ) Â, F i g u r e 6 . 0 2 ) .  Intramolecular Atomic Distances  C4-C43  a r e n o t as  120 127 116 127 118 110 110  .0(2) .3(3) .4(2) .4(2) .5(2) .2(2) .2(3)  Selected  Bond  Similarly, be  responsible  (47b).  these for  formation  Although  benzo-aromaticity, thrust  the  methyl-methyl of  the  vinyl-vinyl i t  will,  bridgehead  for hand,  deter  the  from  methyls  product  formation.  will  relieve  crystallographic from  the  reaction  molecular  vinyl-vinyl  some  bridged  the  6.08).  This  increases  the  calculated  This  reasonably  a d d i t i o n product  to  explains (47b)  over  not  disrupt  calculations,^-'-^  aromatic  methyls  increased  cycloaddition,  strain  (path  calculated are the 2.9  Â;  sole  the v i n y l - v i n y l  on  thereby  the  other  i i ) . Consistent  methyl-methyl  about  methyl-methyl the  does  energy  steric  about  benzocyclooctatetraene  i n c r e a s i n g the r e q u i r e d a c t i v a t i o n  species,  reduced  to  could  program-'--'-^  are  thought  tension  the  distances  are  modelling  towards  Benzo-vinyl  data,  modelling  by  observed  cycloaddition  increasing tension (path i , Figure easily  interactions  3.0  Â.  whereas, distances formation  distances  Going  calculated  with  to  the  methyl-methyl  benzo-vinyl bridging to of  about the  a d d i t i o n product.  3.1  Â.  benzo-vinyl  Flgure  6.08  Geometric  Requirements  a d d i t i o n Products from Benzobarrelene  for 47.  the  Formation of  [2+2]  Cyclo-  PART V I I .  PHOTOCHEMICAL [ 1 . 3 ] SHIFTS IN BENZOSEMIBULLVALENES  Departing interesting  phenomenon  investigation the  slightly  from was  the main  noticed  o f benzobarrelenes.  benzosemibullvalene  benzosemibullvalene  frequently  interesting  feature  here  i s  i n Figure  7.02  a r e some  Consistent  with  the  a  A  this  the  to  i n unusual  whereby another  description  the Introduction. shifts  an  photochemical  shift general  these  thesis,  photoprocess  [1,3]  of  that  photochemically reversible resulting Shown  secondary  occurred.  t h e s e s h i f t s was g i v e n i n S e c t i o n V I  of  throughout  The  undergoes  focus  However,  of the  a r e found  t o be  photostationary  states.  benzosemibullvalenes  studied  f o r this  reactions  proceed  shift.  either  through  excited states. C2a'^6c  bond  the i n i t i a l l y  Figure  7.01  their These  followed  l i t e r a t u r e , •'-•^^  singlet  (Sj^) o r  [1,3] s h i f t s by  come  recombination  these higher  about  energy from  cleavage  o f the  b e t w e e n t h e C^-C^^ p o s i t i o n s o f  c l e a v e d s p e c i e s ( F i g u r e 7.01).  Mechanism o f [1,3] S h i f t  triplet (T2)  Photoconversion  hv  hv Ratio  29a  X.Y  =  CO2CH3  29b  42a  X,Y  =  COPh  42c  X  Ma  Figure  CO2CH3,  =  Y Y  =  X  =  COPh,  X  =  CO2CH2CH3,  =  X  =  COPh,  45a  X  =  C02CH(CH3)2,  45c  X  =  COPh,  =  Y =  CO2CH3  -< 4  8  2  43b  2  8  COPh  441  9  1  CO2CH2CH3  =  44b  2  8  COPh  45Î  9  1  C02CH(CH3)2  45b  1 : 9  Y  =  8 : 2 (acetone sens.)  CO2CH3  29c  X,Y  43£J  X  =  CO2CH3,  Y  43Ê  X  =  COPh,  =  7.02  43c  Y  44£  Y  COPh  6  7 : 3 (benzene sens.)  =  Photostationary  Y  States  =  COPh CO2CH3  o f Some B e n z o s e m i b u l l v a l e n e s S t u d i e d .  It  i s interesting  bullvalene is  29e  degenerate.  leads Also  to to  note an  noteworthy  that  identical is  the  1,2-disubstituted benzosemibullvalenes Judging  from  benzosemibullvalenes-'-^O benzosemibullvalenes  the  requires  by  [1,3]  shift  compound; finding  the that  results other  a  along  groups,  cleavage,  a  radical  at  the  Cg^,  position,  interconversion  with  some  [1,3]  carbonyl-containing  where  isomerization  the  still  t h e Cgj, p o s i t i o n f o r a r e v e r s e p h o t o c o n v e r s i o n .  since  an e x p l a n a t i o n f o r t h e p h o t o s t a t i o n a r y s t a t e s  retains  observed.  in  other  shift  after  carbonyl  This,  of  of  substitutent  o f t h e i n t e r m e d i a t e c a n be r e s o n a n c e  by the adjacent c a r b o n y l . I n s i t u a t i o n s is  benzosemi-  conversion.  the  a d j a c e n t t o the bond c l e a v e d . T h i s i s u n d e r s t a n d a b l e bond  of  photolysis  g a v e no s u b s t a n t i a l  observed  studied  the  this  initial  stabilized substitutent c a r b o n y l on  turn,  suggests  EXPERIMENTAL  GENERAL PROCEDURES  Melting Points  (MP)  Melting points Fisher-Johns  hot  stage  Infrared Spectra  a  liquid  for  sodium  film  potassium  mixture Model All  in B  and  a  assignment  strong,  mg  Solid  of  samples  pellet.  made)  Bruker  nuclear  on B r u k e r WH-400  AC-200  samples  1710  on  a  Fourier  were  prepared  in  as  prepared corrected  pellets  die per  and  with  prepared  by  grinding  pressing  with  a  maxima  the  Carver  square i n c h  (cm"-'-) f o l l o w e d b y  (psi).  (^max^  signal  Abbreviations:  intensity  vs  =  very  spectra  were  broad.  (NMR) resonance  MHz),  (ppm)  o f KBr  Absorption  magnetic  The  prepared  mg  pounds  parenthesis.  (200  were  evacuated  17,000  reported.  million  100  186-0002 at  spectrometers.  S s c a l e i n parts per  were  with  reciprocal centimeters (if  Oily  Pellets  sample  press  were  on a P e r k i n - E l m e r  background c o r r e c t e d w i t h a f r e s h l y  N u c l e a r Magnetic Resonance S p e c t r a  recorded  determined  c h l o r i d e p l a t e , background  s = s t r o n g , m = medium, b r =  Proton  were  uncorrected.  measured  sodium  Perkin-Elmer  peaks in  a  bromide 2  were  (KBr),  laboratory  major  reported  on  bromide  approximately  are  spectrophotometer.  chloride.  potassium blank  spectra  infrared  as  a p p a r a t u s and  (°C),  (IR)  Infrared transform  i n degrees C e l s i u s  Varian  chemical with  (-'-H  NMR)  XL-300  (300  MHz),  s h i f t s were r e c o r d e d  tetramethyl  silane  (TMS)  and in  as  the the  internal  standard  the  solvent  of  protons,  at  unless  0  ppm.  Deuteriochloroform  otherwise  coupling  stated.  constant(s)  Signal  ( J ) , and  in parenthesis. Abbreviations: s = singlet, q = q u a r t e t , dd = doublet  the f o l l o w i n g instruments:  75  MHz,  decoupled ppm  and  Bruker  reported  from  s o l v e n t was C D C I 3 u n l e s s parenthesis  Bruker  WH-400  and attached proton  were  multiplicity, assignment  d = doublet,  number  are  t  =  given  triplet,  of doublets, m = multiplet.  Carbon n u c l e a r magnetic resonance on  ( C D C I 3 ) was u s e d a s  at test  the  (•'-^C NMR) s p e c t r a w e r e  AC-200 a t 50 MHz, V a r i a n X L - 3 0 0  100  MHz  at  f o r b r o a d b a n d p r o t o n (BB)  (APT) e x p e r i m e n t s .  Chemical s h i f t s i n  s i g n a l s o f t h e BB d e c o u p l e d  otherwise  recorded  s t a t e d . Assignment  s p e c t r a . The  ( i f made)  is i n  f o l l o w i n g e a c h 5.  Mass Spectra (MS) Low Kratos low  and  MS-50  high  resolution  instrument.  resolution  and  Gas  high  mass  spectra  chromatography  resolution,  were  were mass  recorded spectra  carried  out  MS-80RFA i n s t r u m e n t .  I o n i z a t i o n f o r t h e a b o v e was a c h i e v e d  bombardment  electron volts  (DCI)  70  s p e c t r a w e r e done o n a D e l s i  ammonia on  at  mass  spectrometer  o-nitrobenzoic  acid  matrix  are reported w i t h r e l a t i v e  (GC-MS),  on a K r a t o s by  electron  (EI). Desorption  chemical  Nermag  spectrometer  RlO-lOC  a s t h e C I g a s . F a s t a t o m bombardment  a n A E I MS-9  with a  with  ionization  (FAB) s p e c t r a were  Xenon  bombardment  on  using recorded to  an  o f t h e s a m p l e . Mass t o c h a r g e r a t i o s (m/z)  intensities  i n parenthesis.  Ultravlolet  s p e c t r a (UV)  Ultraviolet UV/Vis  s p e c t r a were measured  spectrophotometer  on  in acetonitrile  a  Perkin-Elmer  Lambda-4B  ( C H 3 C N ) . The A^^^  i n nanometers f o l l o w e d by t h e e x t i n c t i o n c o e f f i c i e n t  reported  (e).Abbreviations:  sh = s h o u l d e r .  E l e m e n t a l A n a l y s e s (EA) All  elemental  analyses  were  performed  by  the  departmental  m i c r o a n a l y s t , M r . P. B o r d a .  Crystallographic All  Analyses  X-ray  diffractometer Pokkulurl,  crystal by  s t r u c t u r e s were d e t e r m i n e d  either  Dr.  o r D r . R. J o n e s  J.  Trotter,  on a R i g a k u  4-circle  Dr. S.J. R e t t i g ,  D r . P.R.  o f t h e UBC D e p a r t m e n t o f C h e m i s t r y .  Chromatography Gas  chromatographic  Hewlett  Packard  detector.  Signal  attachment. 15m  5890  (GC)  instrument  i n t e g r a t i o n was  Three  analyses  fused  fitted  done  silica  with  (J&W  Scientific  Inc.),  with a  and  a  Inc.), 20m  performed a  flame  on  Packard  columns  were  a x  15m  x  a  ionization  Hewlett  capillary  X 0.25mm DB-1 c o l u m n (J&W S c i e n t i f i c  column  were  3392A  used,  a  0.25mm  DB-17  0.21mm c a r b o w a x  column  (Hewlett Packard). Preparative method-'-^l are  using  specified  column 230-400  chromatographies mesh  silica  i n each p r e p a r a t i o n .  were  done  g e l (Merck) .  by  the  Flash  Eluting solvents  Thln l a y e r chromatography p r e p a r a t i v e column  S o l v e n t s and  on p r e - c o a t e d s i l i c a  grade  further  solvents  were  purified  Reagents  were  used  purification  gel plates  prior  to  each  ( t y p e 5554, M e r c k ) .  unless  otherwise  stated.  Other  a c c o r d i n g t o known procedures-'-22 p r i o r  directly  without  further  to use.  purification  unless  stated.  Photochemical L i g h t Photolyses  Sources were  carried  medium p r e s s u r e m e r c u r y desired  out  with  lamp o r a PRA  UV-12  wavelengths  (A > 260 nm), filter  performed  s o l v e n t s were u s e d f o r p h o t o c h e m i c a l e x p e r i m e n t s  without  The  was  Reagents  Spectral  otherwise  (TLC)  P y r e x (A >  for 290  the nm),  either  lamp or  a  450 W a t t H a n o v i a  nitrogen  were  laser  (337  a c h i e v e d by u s i n g  uranium  glass  (A  >  nm) Corex  330  nm)  quartz  or  in  ml  sleeves.  Solution  Photolyses  Analytical  photolyses  were  conducted  in  P y r e x t u b e s a n d some p r e p a r a t i v e p h o t o l y s e s  were  Pyrex  glass  tubes,  degassed sealing carried degassed  both  by  repeating  under out by  photolysis.  sealed  in  nitrogen. an  bubbling  with  the  with  scale  well-^-^^  caps.  nitrogen  for  1/2  the h  10  Samples  were  twice  and  cycle  preparative with  ml  performed  freeze-pump-thaw  Larger  immersion  ground  0.2  photolyses sample  prior  were  solution  t o and  during  Solid  State Photolyses Analytical  evacuated  and  studies  filled  (4-10  with  p h o t o l y s e s were c o n d u c t e d  mg)  nitrogen  in  10  ml  were  conducted  prior  to p h o t o l y s i s .  Pyrex  in  phototubes  NMR  tubes  Preparative  evacuated  and  f i l l e d w i t h n i t r o g e n f o r c r y s t a l l i n e photolyses. For l a r g e r conversions, the  crystals  a  were  sandwich  and  crushed  two  Pyrex  in  this  thesis,  the  a n i t r o g e n a t m o s p h e r e makes no d i f f e r e n c e  or  product  I.  SYNTHESIS OF  microscope  p h o t o l y z e d w i t h o u t a n i t r o g e n atmosphere  state photolyses performed of  between  slides  as  (in a l l solid  presence  or  to the observed  absence  reactivity  ratios).  STARTING MATERIALS  Dimethyl 1,4-Dihydro-l,4-ethenonapthalene-2,3-dicarboxylate (29)"" F o l l o w i n g the procedure o f G r o v e n s t e i n et A l . ^ ^ , naphthalene 0.44 in  (108 g, 0.84  mole),  and  mole), dimethyl a c e t y l e n e d i c a r b o x y l a t e  hydroquinone  (3 g, 27 mmoles) was  8 hea-vy w a l l e d P y r e x t u b e s s u c h t h a t e a c h t u b e  full.  The  tubes  p r o o f oven. of  The  w e r e h e a t e d a t 170-180 °G  dark brown r e a c t i o n m i x t u r e  chloroform  and  chromatographed  a c e t a t e a n d p e t r o l e u m e t h e r ( 3 0 - 6 0 °C) solvent.  The  first  band  the  desired  14.5  g of c o l o r l e s s prisms MP:  compound  105-106 °C  a mixture of  was  29.  on (5  (lit.^^  :  95  naphthalene,  12%).  105.0-105.5  was  °C).  and  v/v) the from  g,  vacuum  less  than  i n an  explosion-  dissolved  silica  Recrystallization (yield  s e a l e d under  f o r 3 days was  (56  gel as  in using the  half  500  ethyl eluting  second band methanol  ml  was gave  IR 1307  (KBr)  ( s ) , 1245  5.25  v^^y^:  (m,  C-H),  1052  (s)  cm-1.  ( v s , C-0),  ^H  NMR  (400  (dd,  2H,  J = 4,3  l^C  3070  NMR  MHz)  5:  Hz,  (75  7.4-6.9  6:  1 2 4 . 3 7 , 1 2 3 . 0 2 , 5 2 . 1 5 , 50.20 MS 152  ( E I ) m/e:  (100),  128  UV  270  6H,  3.78  165.83  (vs,  C=0) ,  aromatic  ( s , 6H,  (C=0),  (s) ,  and  methyl)  147.39,  1437  vinyl),  ppm.  144.59,  138.96,  ppm.  (M+,  30),  238  (16),  210  1300)  nm.  (96),  183  (67),  F o u n d : C,  71.22;  (55).  (CH3CN): 230  sh  (e 5 4 6 0 ) , 275  calcd.  for  Ci6H]^404: C,  structure  of  Anal. H,  (m,  bridgehead),  MHz)  1718  (e  7 1 . 1 0 ; H,  5.22.  5.30. The  diffraction  analysis.  tetragonal, (2)Â3,  Z  this  The  crystal  s p a c e g r o u p 14, =  8,  =  compound  was  data  confirmed  were  as  g/ml,  an  X-ray  f o l l o w s : C]^gH]^404,  a = 18.572(4)Â, c = 7.957  1.31  by  (7)Â,  V  =  2744  R = 0.034. D e t a i l s w e r e p u b l i s h e d i n  a p a p e r by J . T r o t t e r .  1,4-Dihydro-l,4-ethenonaphthalene-2,3-dicarboxylic To added  a s o l u t i o n o f 29  650  refluxed 200  ml  basic to  for of  2  of h,  and  combined  a  diethyl  white  ether was  M  81 mmole) i n 150  NaOH^^q). to  to  then  room  twice  were  The  temperature,  neutralized  with  washed  This 500 twice  ml  was ml with  (40) of  resulting  remove u n r e a c t e d  precipitate.  extracted extracts  9.6 cooled  aqueous l a y e r  give  again  ml  ( 2 1 g,  Acid  solution  was  washed  concentrated  cooled  t o room  diethyl 200  was  with  starting material.  with  of  and  ethanol  ml  of  The  HCl^^q)  temperature ether.  The  water,  dried  o v e r MgSO^, a n d of  diacid  40  acetonitrile  evaporated as  a  under  white  gave c o l o r l e s s  reduced  solid  pressure  to  give  17.0  g  ( y i e l d 87%) . R e c r y s t a l l i z a t i o n f r o m  prisms.  MP: 2 0 4 - 2 0 5 °C. IR  ( K B r ) Un,ax: 3 1 0 0 - 2 3 0 0  ( b r , OH),  1700-1450  ( s , C=0) ,  1279  ( s , C-0) c m ' l . ^H (m,  NMR  6H, a r o m a t i c a n d v i n y l ) , ^H NMR  vinyl),  5:  10.00  ( 4 0 0 MHz, a c e t o n e - d g )  NMR  NMR  5:  7.4-6.9  (100),  (m,  6H,  ppm.  aromatic  and  ppm.  ( 4 0 0 MHz, C D C I 3 ) 5: 7.4-6.9 (m, 6H, a r o m a t i c a n d v i n y l ) , ppm.  ( 7 5 MHz, DMSO-dg) 5: 167.14  1 3 9 . 5 1 ( C H ) , 124.34 ( C H ) , MS  ( b r s , 2H, OH), 7.4-6.9  5.26 ( d d , 2H, J = 4,3 H z , b r i d g e h e a d )  ( d d , 2H, J = 4,3 H z , b r i d g e h e a d ) l^C  (C),  DMSO-dg)  5.79 ( d d , 2H, J = 4,3 H z , b r i d g e h e a d ) ^H  5.79  ( 4 0 0 MHz,  ( E I ) m/e:  242  (0=0),  123.20 ( C H ) ,  (M+,  147.27  ( C ) , 145.68  50.16 (CH) ppm.  3 0 ) , 224 ( 3 2 ) , 198 ( 1 6 ) , 180 ( 3 7 ) , 152  128 ( 3 8 ) . E x a c t mass c a l c u l a t e d  for  242.0579,  CI^HIQOI^:  found  242.0576. UV (CH3CN): Anal.  228 (e 5 7 0 0 ) ,  calcd.  290 s h (e 8 0 0 ) nm.  f o r Cn^ttiQO^:  C, 6 9 . 4 2 ; H, 4.16. F o u n d : C, 6 9 . 4 0 ;  H, 4.26.  I, 4-Dihydro-1,4-ethenonaphthalene-2,3-dicarboxy1ic To 500  ml  chloride 15  h  a of  solution freshly  (17.4 m l , in a  of  40  ( 1 3 . 0 g,  distilled  methylene  0.20  nitrogen  mole).  atmosphere.  The  53.7  mmoles)  chloride  solution  The  Anhydride (41)  solvent  was was and  dissolved added refluxed excess  in  oxalyl for oxalyl  c h l o r i d e were e v a p o r a t e d and from  a  1:4  product  (yield MP: IR  of  benzene  ( K B r ) Umax^ 1^38  125.17 MS  (45).  ( C D C I 3 ) 5: 7.4-7.0  ( C H ) , 124.40  ( E I ) m/e:  5:  to  (m,  recrystallized  give  10.0  g of the  ( C H ) , 45.39  for  and  vinyl),  5.29  ppm. ( C ) , 143.67  ( b r i d g e h e a d CH) 152  ( C ) , 139.58  ppm.  (100),  128  (40),  76  224.0473, f o u n d 224.0472.  CI^HQO^:  (e 1 7 5 0 0 )  calcd.  cm'^.  aromatic  224 (M+, 4 0 ) , 180 ( 3 8 ) ,  (CH3CN): 246  Anal.  6H,  160.30 ( C ) , 159.92  E x a c t mass c a l c u l a t e d f o r UV  hexanes  was  ( s , C=0), 1767 ( s , C=0)  2H, J = 4,3 H z , b r i d g e h e a d )  (CH),  :  solid  83%) as p a l e y e l l o w n e e d l e s .  (CDCI3)  H,  remaining  1 2 9 - 1 3 0 «G.  NMR (dd,  mixture  the  nm.  C14H8O3:  C,75.00;  H, 3.60. F o u n d : C, 7 5 . 1 3 ;  3.60.  I, 4-Diphenyl-2-butene-l,4-dione  (55)''^c  F o l l o w i n g t h e m e t h o d o f R.E. L u t z , ' ^ 5 c anhydrous  AICI3  (35  ^  was h e a t e d was  acidified warm  f u n n e l a t a r a t e o f 1-2 t o 50-60 °C  refluxed  at  a l l times.  min  and  crushed i c e .  The  benzene  dried  over  then  ( y i e l d 53%).  After poured  layer  Na2S04,  r e m a i n i n g p r o d u c t was r e c r y s t a l l i z e d b r i g h t yellow needles  (from A l d r i c h )  drops p e r second.  10  water,  for  (180  ml)  and  g, 0.26 m o l e ) s o l u t i o n , u n d e r n i t r o g e n , was a d d e d  15.3 g ( 1 1 m l , 0.10 m o l e ) o f f u m a r y l c h l o r i d e dropping  benzene  The r e a c t i o n  addition, into  was  filtered,  from e t h a n o l  through  to  mixture solution  an e q u a l volume o f  washed and  the  a  4  times  with  evaporated. give  12.4  The g  of  MP:  1 0 8 - 1 1 0 °C ( l i t 7 5 c  1 0 9 - 1 1 0 «C) .  IR  (KBr)  (m,  1650  v^^^:  C=0),  1446 (m), 1323 (m), 1294 ( s ) ,  705 ( s ) NMR 2H,  (300MHz)  vinyl),  7.66-7.60  meta-aromatic) MS  5:  8.09  (m,  (m,  2H,  4H,  para-aromatic),  236 (M+, 2 2 ) , 105 ( 1 0 0 ) ,  2,3 - D i b r o m o - 1 , 4 - d i p h e n y I b u t a n e - 1 , 4 - d l o n e C r y s t a l s o f compound 55 ( 1 0 . 8 115  an  equimolar  ml  nitrogen.  of  dry  chloroform  amount  The  of  ethanol  (s,  (m,  4H,  7.56-7.49  reaction  was  :  chloroform  (1  :  45.8  and  mmoles)  to  this  (7.32  stirred to  77 ( 4 2 ) .  (56)^^^  g,  bromine  a d d i t i o n a l 45 m i n a n d e v a p o r a t e d from  8.01  ppm.  ( E I ) m/e:  in  ortho-aromatic),  a  at white  5)  was  g,  room  were  dissolved  added  2.53  dropwise  ml)  under  temperature  solid.  for  an  Recrystallization  g a v e 14.6 g o f c o l o r l e s s  prisms  ( y i e l d 81%). MP: IR ^H aromatic),  1 7 6 - 1 7 9 °C (KBr) NMR  lit.^^b  3^79 OQ d e c o m p . ) .  v^^^:  1681 ( s , C=0), 1596 (m), 1446 (m), 1289 ( s ) cm'^.  (300  MHz,  7.05-7.01  meta-aromatic), MS  form,  6.15  ( E I ) m/e:  Benzene-dg)  (m,  2H,  ( s , 2H, H C B r ) 316 ( 0 . 1 , M+  5:  7.86-7.78  para-aromatic),  (m,  4H,  6.98-6.90  ortho(m,  4H,  ppm.  - B r ) , 236 ( 1 9 , M+  -  Br2),  208  (11),  105 ( 1 0 0 ) , 77 ( 7 9 ) . MS  ( D C I , NH3) m/e:  237 ( 2 7 ) , 105 ( 1 0 0 ) ,  414 ( 8 , M + NH4+)_  77 ( 2 3 ) .  397 ( 7 , M+ + 1 ) , 254 ( 1 5 ) ,  l,4-Diphenyl-2-butyne-l,4-dione Dibromide 80  mmoles),  4.5  h. The  56  and  108  of  resulting  brown  1261  (s)  mmoles),  c o o l e d t o room  solution (to  triethylamine  1 1 0 - 1 1 1 °C  and  were  evaporated  to  polymerization)  (yield  (11.1  ml,  the  colorless  filtered a  solid  from  off.  and  The  promptly  methanol  to  give  55%).  (lit.75a  ( K B r ) Uj^ax^ 16^6  temperature  bromide  was  avoid  g o f brown c r y s t a l s  IR  34.1  triethylammonium  recrystallized  MP:  g,  ml o f d r y benzene were r e f l u x e d under n i t r o g e n f o r  r e a c t i o n was  crystals  4.4  (13.5  (57)'^^  no-m  ( s , C=0) ,  1592  (m) ,  1449  (m) ,  1317  (m) ,  cm-1. NMR  7.73-7.66 (m,  (300 2H,  MHz)  5:  8.22-8.16  para-aromatic),  (m,  7.58-7.51  4H,  (m,  ortho-aromatic),  4H,  raeta-aromatic)  ppm. MS  (EI)  ( 1 0 0 ) , 77  (87).  m/e:  234  (71,  M+),  206  ( 1 1 ) , 178  2,3-Dibenzoyl-1,4-dihydro-l,4-ethenonaphthalene In compound and 1.5 and  a  thick  18  (500  hydroquinone h,  cooled  chromatographed  hexanes  (1  :  came  the  with  activated  9  walled  sealed  mg,  2.14  mmoles),  (150  mg).  The  to  room  using v/v).  desired  vacuum  charcoal  eluting  The  product  tube  first as  and  a  tube  brown in  ( 4 . 0 g,  heated  to  dissolved  mixture  b a n d was  celite  Pyrex  was  (49),  105  (42)  naphthalene  temperature,  an  ( 5 0 ) , 129  of  was  placed  31  mmoles),  180 in  diethyl  °C  chloroform, ether  unreacted naphthalene.  o i l . This diethyl  for  o i l was  and Next  treated  ether, f i l t e r e d ,  and  evaporated  to  afford  Solidification from  from  mg  of  a  scratching  colorless  in  o i l  hexanes  and  NMR 5.42  recrystallization  1649 ( s , C=0), 1594 (m), 1273 ( s ) cm'^.  v^^^:  ( 3 0 0 MHz)  7.45-7.00  (m,  ( d d , 2H, J = 4,3 H z , b r i d g e h e a d )  ppm.  NMR 139.46  (CH),  124.68  (50  5:  MHz)  137.87  5:  (C),  194.52  132.77  16H,  (C=0),  (CH),  aromatic  153.94  128.50  ( C H ) , 1 2 3 . 4 1 ( C H ) , 51.94 (CH, b r i d g e h e a d ) MS  ( E I ) m/e:  UV  vinyl),  ( C ) , 145.02 ( C ) ,  (CH),  128.21  (CH) ,  ppm.  f o r C26H]^802: 3 6 2 . 1 3 0 7 , f o u n d 3 6 2 . 1 3 0 5 .  (CH3CN): 255 (e 2 1 5 0 0 )  Anal,  and  362 (M+, 4 9 ) , 257 ( 3 6 ) , 128 ( 5 5 ) , 105 1 0 0 ) , 77 ( 6 0 ) .  E x a c t mass c a l c u l a t e d  calcd.  nm.  f o r C26H]^802 : C, 8 6 . 1 7 ; H, 5.01.  Found:  C,  85.97;  Acid  Monomethyl  5.00.  I, 4-Dihydro-l,4-ethenonaphthalene-2,3-dicarboxylic Ester  (58) A s o l u t i o n of anhydride  dry  methanol  was  41  refluxed  (9.1 under  g,  40.6  nitrogen  mmoles)  methylene  chloride  and  l a y e r was d r i e d o v e r pressure to afford IR  (liquid  washed  MgSO^,  filtered,  1278 ( C - 0 ) cm-1.  v^^^:  i n 100  300  ml  methanol ml  of  t w i c e w i t h 75 m l o f w a t e r . The o r g a n i c and  evaporated  10.8 g o f a v i s c o u s o i l ( y i e l d film)  in  f o r 2 h . The  was e v a p o r a t e d a n d t h e r e s u l t i n g y e l l o w o i l was d i s s o l v e d  (s),  19%).  1 0 2 - 1 0 3 °C.  IR ( K B r )  of  (yield  benzene : h e x a n e s ( 1 : 5 v / v ) gave c o l o r l e s s p r i s m s . MP:  H,  146  under  reduced  100%).  3 4 0 0 - 2 5 0 0 ( b r , OH), 1719 ( s , C = 0 ) ,  1637  NMR 5.89  (dd,  (300  IH,  MHz)  J  =  5:  5,2  7.3-6.9  Hz,  ( s , 3H, m e t h y l )  l^C  5:  146.19  (C),  ( 7 5 MHz) 145.38  aromatic  5.60  (C=0),  145.26 ( C ) , 139.47  49.79  (CH)  ppm.  MS  (EI)  (100),  128  (30).  Exact  Hz,  (M+,  (C=0),  148.25  (C),  ( C H ) , 139.25 ( C H ) , 124.29  124.25 ( C H ) , 123.15 ( C H ) , 1 2 3 . 1 1 ( C H ) , 52.20  256  vinyl),  ( d d , I H , J = 5,2  166.05  (CH),  m/e:  and  ppm.  166.50  (C),  6H,  bridgehead),  b r i d g e h e a d ) , 4.00 NMR  (m,  (CH3),  49.94  (CH),  2 5 ) , 212 ( 3 1 ) , 196 ( 2 0 ) , 179 ( 1 8 ) , 152  mass  calculated  for  Ci^Hu'^h-  256.0736,  f o u n d 256.0728.  Methyl 2-Benzoyl-l,4-dihydro-l,4-ethenonaphthalene-3-carboxylate (43) To of  a  solution  of  anhydrous methylene  (5.6  ml,  64  s o l v e n t was chloride, benzene. AICI3  a  yellow  Then  1  h  was  and  reaction  the  under  Aldrich)  was  The r e a c t i o n  45  min  under  a  4.4  g  added  in  mixture  was  to  1  d r i e d o v e r MgSO^, chromatographed first  was  (33  2.4  the  1 h . The  crude  liters of  portions at  chloride  for  mmoles)  stirred  and  the  was  then  filtered,  and  evaporated.  eluted  and  in  several  solution  and  oxalyl  refluxed  pressure  i n 180 m l  acyl  of  anhydrous  directly  room  dry  to  temperature  n i t r o g e n a t m o s p h e r e . The d e e p r e d s o l u t i o n  t h e n q u e n c h e d w i t h 300 m l o f w a t e r The  dropwise  redissolved  was  liter.  ( 5 . 5 g, 22 mmoles)  added  reduced  o i l , was  approximately  (from  58  chloride  evaporated  the s o l u t i o n . for  mmoles)  acid-ester  with  10%  total  volume  washed w i t h water  diethyl  The  m a j o r b a n d was 1.4 g o f t h e p r o d u c t a s a w h i t e  (2 x 200 m l ) ,  resulting  ether  reduced  o i l was  i n hexanes.  solid  (yield  The  21%).  R e c r y s t a l l i z a t i o n from hexanes gave p r i s m s . MP:  127-128 °C.  IR  (KBr)  v^^^:  1713  (s,  ester  C=0),  1667 ( s , b e n z o y l  C=0),  1244 ( s , C-0) c m ' l . NMR  ( 4 0 0 MHz)  5: 7.6-6.9  ( d d , I H , J = 6,2 H z , b r i d g e h e a d ) , 3.40  ( s , 3H, m e t h y l ) l ^ c NMR  145.41 (C),  (C),  5.55  bridgehead),  S : 195.60 ( b e n z o y l 0 = 0 ) , 164.14 ( C ) , 1 5 9 . 2 7 ( C ) ,  ( 7 5 MHz) 144.12  (EI)  vinyl),  ( d d , I H , J = 6,2 H z ,  (C),  141.97 ( C ) , 140.27 ( C H ) , 138.03 ( C H ) , 135.69  ( C H ) , 128.52 ( C H ) , 124.55  (CH),  ( C H ) , 123.07 ( C H ) , 52.29 ( C H ) , 5 1 . 6 1 ( C H 3 ) , 4 8 . 8 9 MS  (20),  5.04  and  ppm.  1 3 3 . 3 9 ( C H ) , 128.57  123.25  (m, I I H , a r o m a t i c  m/e:  316  (M-H,  1 1 ) , 284 ( 1 1 ) , 256  124.34 (CH)  (CH),  ppm.  ( 1 2 ) , 211 ( 1 2 ) , 152  128 ( 9 0 ) , 105 ( 1 0 0 ) , 77 ( 3 9 ) . E x a c t mass c a l c u l a t e d  for  C2iH]^603:  316.1100, f o u n d 316.1103. ( H e x a n e ) : 247 {e  UV  Anal. H,  calcd.  for  1 6 8 9 0 ) , 290 s h (e C21HX6O3:  3220)  nm.  C, 7 9 . 7 3 ; H, 5.10. F o u n d : C, 7 9 . 7 5 ;  5.13. The  structure  diffraction triclinic, (8)Â,  a  analysis.  of The  this  compound  crystal  was  data  are  supported as  by  follows:  s p a c e g r o u p P I , a = 9.772 (8)Â, b = 11.034 (2)Â, =  92.58(1)°,  = 111.50(8)°,  an  7 = 97.96(1)°,  V =  X-ray  C2iH]^g03, c  =  8.174  807.8(2)Â3,  Z = 2, Dx = 1.296 g / m l , R = 0.042.  Ethyl  2-Benzoyl-l,4-dihydro-l,4-ethenonaphthalene-3-carboxylate Crystals  of  dry  ethanol  o f 43 ( 4 0 0 mg, and  to  this  1.27 mmole) was  added  were  dissolved  in  (44) 400  ml  4 m l o f c o n c e n t r a t e d H2SO4.  The s o l u t i o n was r e f l u x e d f o r 2 NaHC03^gq^. and  the  with  and  was  solution  dried  over  (1  extracted  MgS04,  solid  neutralized  silica  ( 3 4 0 mg,  under  with  filtered,  : 9 v / v ) as t h e e l u t i n g  band as a w h i t e  starting  and  evaporated  o i l was c h r o m a t o g r a p h e d o n  hexanes  the f i r s t  ethanol  remaining  water,  remaining  by  The  days  with  saturated  reduced  diethyl  pressure  ether,  and  evaporated  gel  using  washed  again.  diethyl  s o l v e n t . The p r o d u c t  The  ether  eluted i n  8 1 % ) . T h i s was f o l l o w e d c l o s e l y  m a t e r i a l 4 3 . R e c r y s t a l l i z a t i o n from hexanes gave  colorless  rods. MP: IR  93-94 °C. (KBr)  1255 ( s , C-0) 1-H 5.55  Umax:  1708  (s,  MHz)  5:  ester  C=0),  7.6-6.9  (m,  1657  (s,  benzoyl  C=0),  cm-1.  NMR  (400  ( d d , I H , J = 6,2 H z ,  bridgehead),  3.85  (q,  bridgehead),  IIH,  5.02  (dd,  2H, J = 7 Hz, C H 2 ) , 0.79  aromatic IH,  J  and v i n y l ) , =  6,2  Hz,  ( t , 3H, J = 7 H z , C H 3 )  ppm. l^C 145.66 (C),  NMR  (C),  6: 195.82 ( b e n z o y l C=0), 1 6 3 . 9 1 ( C ) , 158.74 ( C ) ,  (C),  1 4 2 . 1 1 ( C ) , 140.52  MS  ( C H ) , 138.17  ( C H ) , 128.63 ( C H ) , 124.68  ( C H ) , 61.04 ( C H 2 ) , 52.56  1 3 . 3 1 (CH3)  found  144.36  1 3 3 . 5 1 ( C H ) , 128.85  123.24  (17),  (50 MHz)  (CH),  ( b r i d g e h e a d CH), 49.00  ( C H ) , 136.03 123.36  (CH),  (bridgehead  CH),  ppm.  ( E I ) m/e:  330 (M+, 1 5 ) , 284 ( 1 6 ) ,  256  105 ( 1 0 0 ) , 77 ( 2 0 ) . E x a c t mass c a l c u l a t e d  (15),  152  f o r C22H18O3:  (10),  128  330.1255,  330.1251. UV  (CH3CN) : 251 (e 1 6 5 0 0 )  Anal,  calcd.  f o r C22H18O3:  nm. C, 7 9 . 9 8 ; H, 5.49.  Found:  C,  80.10;  H, 5.47. The  structure  diffraction  of  analysis.  triclinic,  space  this  The  compound  crystal  was  data  supported  are  as  by  follows:  g r o u p P I , a = 10.14(1)Â, b = 11.28(2)Â,  a = 96.31(1)°, ^ = 110.26(9)°, 7 = 95.62(1)°, V =  an  X-ray  €22^18^3'  c = 8.41(1)Â,  886.8(2)Â3,  Z  =  2,  Dx = 1.237 g / m l , R = 0.043.  Isopropyl 2-Benzoyl-1,4-dihydro-1,4-ethenonaphthalene-3-carboxylate Compound  43  (400  mg,  1.27  mmole)  dissolved  dry  i s o p r o p a n o l was r e a c t e d w i t h c o n c e n t r a t e d  at  reflux  for  3  o f 67 : 2 9 . The the  days.  G.C.  reaction  isopropanol  was  evaporated.  showed  an  w i t h w a t e r , d r y i n g o v e r MgS04, f i l t e r i n g , pressure gel  gave  a  u s i n g a 1:9  eluent  gave  yellow  108  mg  f o l l o w e d c l o s e l y by  of  45  of i n  starting  the  1270  77-78 °C.  IR  (KBr)  (dd,  bridgehead), J  diethyl  1^95  of  ether  43  (180  ether,  washing  under  reduced  this :  mg,  o i l on  hexanes  (yield  and  25%).  45%  silica as  the  This  was  recovered).  needles.  (s, ester  C=0),  1666 ( s , b e n z o y l  C=0),  ( s , C - 0 ) . 711 ( s ) c m ' l . NMR  5.57  Umax^  with  f i r s t band  material  of  ( 4 3 : 45)  s a t . NaHC03(^q)  and e v a p o r a t i n g  R e c r y s t a l l i z a t i o n o f 45 f r o m h e x a n e s g a v e MP:  with  diethyl  ml  H2SO4 ( 1 . 2 m l ) a n d s t i r r e d  o i l . Chromatography  (v/v) mixture  200  equilibrium ratio  neutralized Extracting  in  (45)  ( 3 0 0 MHz)  IH,  J  4.76  = 6 Hz, m e t h y l ) ,  =  S: 6,2  7.6-6.95 Hz,  ( s e p t e t , IH, 0.73  (m,  I I H , aromatic  bridgehead), J  =  6  Hz,  and  vinyl),  5.01 ( d d , I H , J = 6,2 H z , CH(CH3)2),  ( d , 3H, J = 6 H z , m e t h y l )  ppm.  ^-^^  ^H,  ^•^C NMR (75 MHz) 8: 196.07 ( b e n z o y l C=0) , 163.50 (C) , 158.45 (C) , 145.87 ( C ) , 144.53 ( C ) , 142.21 ( C ) , 140.78 (C),  133.68  ( C H ) , 138.24  ( C H ) , 136.23  ( C H ) , 129.10 ( C H ) , 128.77 ( C H ) , 124.80 ( C H ) , 124.58 ( C H ) .  123.46 ( C H ) , 123.38 ( C H ) , 69.13 ( i s o p r o p y l  C H ) , 52.69 ( C H ) , 49.02 ( C H ) ,  21.19  The  (methyl),  21.14  (methyl)  ppm.  above  assignments  were  s u p p o r t e d b y a n APT. MS ( E I ) m/e: 105  (100),  77  344  (M+, 7),  (21). E x a c t  mass  284  (13), 256  calculated  (12), 128 (15),  forC23H2o03: 344.1412,  f o u n d 344.1418. UV  (CH3CN) : 251 (e 14500) nm.  Anal, calcd.  f o r C23H20O3: C, 80.21; H, 5.85.  Found:  C,  80.36;  H, 5.90. The  structure  was  supported  by an X-ray d i f f r a c t i o n  The c r y s t a l d a t a a r e a s  follows:  P2i/c,  b = 20.013(5)Â, c = 12.556(3)Â, ^ = 93.32(2)°,  V  a  =  =  7.402(3)Â,  1856.8(9)À3,  Z  =  C23H2o03>  4,  =  monoclinic,  analysis.  1.232  g/ml,  I, 4-Dihydro-1,4-ethenonaphthalene-2,3-dicarboxy1ic  space  R  Ac i d ,  group  =  0.036.  Diethylamine  Monosalt (48) Crystals (0.3  of diacid  40  (300  mg,  1.2  a  white  addition was to  diethylamine  m l , 2.9 m m o l e s ) , a n d 15 m l o f e t h y l a c e t a t e w e r e p l a c e d i n a 50 m l  r o u n d b o t t o m f l a s k . The s o l u t i o n was r e f l u x e d as  mmoles),  was  dissolved  o f a p p r o x i m a t e l y 30 m l o f e t h y l  slowly form.  precipitate  The  cooled  to  resulting  room  f o r 20 m i n a n d t h e  at reflux acetate.  temperature  colorless  rods  with  The  allowing were  clear  a  salt,  further solution  f o r crystals  suction  filtered  ( 2 6 0 mg, y i e l d  (m),  69%) .  MP:  1 6 3 - 1 6 4 °C.  IR  (KBr)  U[„ax-  ^058  (br  s) ,  2772  ( b r s ) , 2507 ( b r m) , 1700  1 6 2 1 ( s ) , 1524 ( s ) , 1466 ( s ) , 1371 ( s ) cm"!.  aromatic  NMR  ( 3 0 0 MHz)  and  vinyl),  5: 9.25 5.78  4H, J = 7 H z , C H g ) , 1.30 MS  ( E l ) m/e:  ( b r s, 2H, a c i d  OH),  7.4-6.8  (m,  ( d d , 2H, J = 4,3 H z , b r i d g e h e a d ) ,  ( t , 6H, J = 7 H z , C H 3 )  6H,  3.10 ( q ,  ppm.  (no M+ p e a k ) 242 ( 4 ) , 224 ( 3 2 ) , 198 ( 4 0 ) , 180  (25)  152 ( 1 0 0 ) , 128 ( 4 0 ) . MS  ( F A B ) m/e:  UV  (CH3CN): 223 s h (e 9 9 7 0 ) , 290 (e 1 6 5 0 )  Anal.  316 (M + 1 ) .  calcd.  for  nm.  C]^8H2i04N: C, 6 8 . 5 5 ; H, 6.71; N, 4.44. F o u n d :  C, 6 8 . 5 5 ; H, 6.81; N, 4.40.  1,4-Dihydro-l,4-ethenonaphthalene-2,3-dicarboxylic  Acid,  Pyrrolidine  Monosalt (49) Diacid  40  (300  mg,  1.8 mmoles) w e r e r e f l u x e d form was  a  white  added  to cool  at  slowly  1.2  i n 15 m l  precipitate. reflux  mmoles)  to  of  and  ethyl  Approximately  dissolve  the  pyrrolidine acetate  75  ml  product.  1 8 5 - 1 8 7 °C.  IR  (KBr)  u^iax-  10  min  ml, to  of  ethyl  acetate  This  was  allowed  t o f o r m 230 mg o f r o d s a f t e r f i l t r a t i o n  MP:  for  (0.15  (yield 61%).  ^011 ( b r s ) , 2790 ( b r m) , 1578 ( v s ) , 1463 ( v s ) ,  1360 ( v s ) , 751 ( s ) cm-1. ^H NMR aromatic  and  ( 3 0 0 MHz) vinyl),  5: 9.58 5.72  ( b r s, 2H, a c i d OH), 7.34-6.88  ( d d , 2H, J = 4,3 Hz, b r i d g e h e a d ) ,  (m,  6H,  3.34  (m.  4H, 2 X NCH2), 2.05 (m, 4H, CH2-CH2-CH2-CH2) ppm. MS  ( F A B ) m/e:  314 (M + 1, 2 2 ) , 72 ( 1 0 0 ) . 290 (e  UV (CH3CN): 223 s h (e 8 0 5 0 ) , Anal, calcd.  f o r Ci3Hi^904N:  1 2 8 0 ) nm.  C, 6 9 . 0 0 ; H, 6.11;  N,  4.47.  Found:  C, 6 8 . 8 7 ; H, 6.07; N, 4.40.  1,4-D i h y d r o - 1 , 4 - e t h e n o n a p h t h a l e n e - 2 , 3 - d i c a r b o x y l i c  Ac i d ,  Pyrrolidine  D i s a i t (50) D i a c i d 40 ( 7 0 mg, 0.29 mmole) a n d p y r r o l i d i n e in  4  small to  ml  white  give  results  of  acetonitrile needles.  80  mg  of  i n removal  melting  of  the  were r e f l u x e d  The  crystals  the s a l t  of  one  crystals  f o r 45 m i n a n d c o o l e d t o g i v e  were  (yield  ( 4 1 mg, 0.58 mmole)  briefly  suction  70%). Prolonged  equivalent followed  of  by  suction filtration  pyrrolidine  their  filtered  and  subsequent  r e s o l i d i f i c a t i o n as t h e  mono-salt. MP: ~ 90 °C IR  (decomposition).  ( K B r ) v^^^:  2979  ( b r s ) , 2773 ( b r m), 1558  ( v s ) , 1464 ( v s ) ,  1386 ( s ) , 716 (m) cm"!. NMR 6.95-6.85  (400  ( 4 H , m, a r o m a t i c  3.00 (m, 8H, 4 X NCH2), MS  MHz,  ( E l ) m/e:  CDCI3)  6:  and v i n y l ) ,  7.30-7.20 5.50  (br  (m, s,  ( F A B ) m/e:  2H,  aromatic), bridgehead),  1.75 (m, 8H, 2 x CH2CH2) ppm. (no  M+)  242  ( 5 ) , 224 ( 4 8 ) , 198 ( 3 8 ) , 180 ( 3 9 ) ,  152 ( 1 0 0 ) , 128 ( 5 5 ) , 70 ( 9 1 ) . MS  2H,  385 (M + 1 ) .  UV (CH3CN): 223 s h (£ 6 5 0 0 ) ,  290 (e  2000) nm.  1,4-Dihydro-l,4-ethenonaphthalene-2,3-dlcarboxylic Acid Disait  (51) Diacid  40  (300  mg,  1.2  2.2 mmoles) w e r e r e f l u x e d  i n 20  resulting  precipitate  was  of  white  a  dry  gave  Ethylenediamine  colorless  powder  mmole) ml  ethyl  suction  (yield  needles.  of  and e t h y l e n e d i a m i n e  filtered  97%).  These  acetate  for  to  (0.15 ml, 1  h.  give  Recrystallization  c r y s t a l s were i n s o l u b l e  The  352  from  mg  water  i n chloroform,  acetone, benzene, and a c e t o n i t r i l e . MP: IR 1455  235-238  ( K B r ) Un,ax: 3100  (m), 1386 NMR  vinyl),  5.70  2 X NH2), MS  °C.  ( s ) , 711 (400  (br  s) ,  1636  (s) ,  MHz,  DMSO-dg)  ( s , 4H, CH2-CH2)  ( E I ) m/e:  (s) ,  1500  (s) ,  (m) c m " l . 5:  7.3-6.8  ( d d , 2H, J = 4,3 H z , b r i d g e h e a d ) ,  2.78  1559  (m,  6H, a r o m a t i c  5.0-4.5 ( v e r y b r  s,  and 4H,  ppm.  (no M+ p e a k ) 242  ( 5 ) , 224  ( 3 1 ) . 198  ( 3 7 ) , 152  (100),  128 ( 4 8 ) . MS  ( F A B ) m/e:  UV  (CH3CN): 223 s h (e 4 1 6 0 ) ,  Anal, C, 6 3 . 5 4 ; H,  calcd. 6.00;  303  (M + 1 ) . ( 6 500)  290  f o r C]^6Hi^804N: C, 6 3 . 5 7 ; H, N,  nm. 6.00;  water  Found:  Acid,  Rubidium  (52) A c i d 40  and  9.27.  9.29.  1,4-Dihydro-1,4-ethenonaphthalene-2,3-dicarboxylic Disait  N,  to  this  ( 2 0 0 mg, was  0.8  added  ( 1 . 6 mmole, A l d r i c h ) .  mmole) was 0.1  ml  dissolved  of  The s o l u t i o n  50% was  i n 12 m l o f a c e t o n i t r i l e  (w/w)  rubidium hydroxide i n  diluted  t o 17  ml,  stirred  at  reflux  solid  for  (yield  i n a n NMR  30  m i n , c o o l e d , a n d f i l t e r e d t o g i v e 2 7 1 mg o f a w h i t e  8 2 % ) . R e c r y s t a l l i z a t i o n by  tube  gave c o l o r l e s s  slow  evaporation  of  methanol  needles.  MP: > 300 °C. IR  (KBr)  v^^y.:  3400-3000  ( b r s ) , 1569  ( v s ) , 1542  ( v s ) , 1371  (vs)  aromatic  and  cm'-'-. NMR vinyl),  5.10 ^H  5.15  (300  MHz,  CD3OD)  6:  7.26-6.80  ( d d , 2H, J = 4,3 H z , b r i d g e h e a d )  NMR  ( 3 0 0 MHz,  D2O)  6: 7.45-7.00  ( d d , 2H, J = 4,3 H z , b r i d g e h e a d ) 413 (M + 1 ,  (m,  ppm. (m, 6H, a r o m a t i c  MS  ( F A B ) m/e:  UV  (CH3OH): 229 (e 1 1 0 0 0 ) , 288 s h (e 1 4 0 0 ) nm.  40 ( 2 0 0 mg,  B a ( O H ) 2 . 8 H 2 0 ( 2 5 2 mg,  together of  vinyl),  7 ) , 4 1 1 ( 9 ) , 238 ( 5 3 ) , 85  (100).  Acid,  Barium  (53) Diacid  and  and  ppm.  1,4-Dihydro-l,4-ethenonaphthalene-2,3-dicarboxylic Disait  6H,  0.8 mmole) d i s s o l v e d 0.8 mmole) i n 4  ml  f o r 3 h . The r e s u l t i n g p r e c i p i t a t e  i n 10 m l o f a c e t o n i t r i l e of  water  were  refluxed  was f i l t e r e d t o g i v e 199 mg  a w h i t e powder ( y i e l d 6 6 % ) . MP: > 300 °C.  5.16  IR  ( K B r ) Ujjjax: 1645 (m) , 1559 ( v s ) , 1455 ( s ) , 1413 ( s ) cm'^.  %  NMR  ( 3 0 0 M H z , D2O)  5: 7.5-7.0  ( d d , 2H, J = 4,3 H z , b r i d g e h e a d ) MS  ( F A B ) m/e:  UV  ( H 2 O ) : 228 s h (e 2 2 0 0 ) ,  (m,  6H,  aromatic  ppm.  379 (M+-f1, 2 9 ) , 356 ( 2 0 ) , 186 ( 2 2 ) . 265 (e  1 9 0 0 ) nm.  and  vinyl),  1,4-Dihydro-1,4-ethenonaphthalene-2,3-dlcarboxylic acetophenone Monosalt  and  for  20  min  in  1  ml  off-white solid and  then  diethyl  solid  (50 mg,  reflux to  a  0.37  stirred  f o r another yellow  70%).  A l l  attempts  to  the  salt  in  ml  of  The  give  in  temperature clear yellow  o i l , scratched to  as  room  20 m i n .  filtered  3  mmole, A l d r i c h )  at  and  failed  in  to 76  a  solid  mg  of  recrystallize solution  an the  dissociates  t h e amine s l o w l y p o l y m e r i z e s t o a d a r k brown o i l .  IR 1445  111-113  °C.  ( K B r ) Unjax^  ( v s ) , 1359 NMR  3H,  CH3)  2958 ( b r s ) , 2631  (vs)  cm'^.  (300  MHz,  a r o m a t i c and v i n y l ) ,  (dd,  m/e:  378  UV  (CH3CN): 230 calcd. 5.08;  Anhydrous  9.36 J  1694  (s) ,  ( b r s, OH),  =  4,3  Hz,  1579  (vs) ,  7.8-6.7 (m,  bridgehead),  lOH, 2.55  nitrogen  252  ( 6 ) , 225  ( 1 3 ) , 55  s h (e 1 1 4 0 0 ) ,  C22H19O5N: C,  7 0 . 0 2 ; H,  333  (54).  (e 3100)  5.07;  N,  nm.  3.71.  Found:  3.75.  p-xylene (47  4 ) , 352  (€ 3 7 0 5 0 ) , for  N,  7-valerolactone a  2H,  (M + 1 ,  4-(2,5-Dimethylphenyl)-pentanoic  under  5:  (br s) ,  ppm.  (FAB)  7 0 . 1 3 ; H,  CDCI3)  5.65  MS  Anal. C,  mmole) d i s s o l v e d  ether,  (yield  have  MP:  (s,  at  concentrated of  0.29  w e r e m i x e d t o g e t h e r and  and  s o l u t i o n was  (70 mg,  3'-aminoacetophenone  2 ml a c e t o n i t r i l e  m-Amino-  (54)  C r y s t a l s o f d i a c i d 40 acetonitrile  Ac i d ,  Acid (60)^^  (106  ml,  atmosphere  g,  0.50 and  1.00 mole, to  mole, from this  from  Aldrich)  Aldrich) was  were  added  and  stirred anhydrous  AICI3  (70  g,  0.55  mole)  as  a  The s o l u t i o n was h e a t e d t o r e f l u x The  solution  was  then  solid  over  f o r 15 m i n a n d  poured  over  MgSO^,  solid  (yield  filtered,  and  IR 1428  evaporated t o give  of  0.5  HCl^g^  h.  evolved.  i c e , diluted  ( t o remove  with  Al(0H)3),  dried  117 g o f a l i g h t  yellow  amorphous  solid.  113.5 o c ) _  ( K B r ) Ujnax'- 3 2 0 0 - 2 6 0 0 ( b r s , OH), 1 7 2 3  ( s , G=0) ,  1460  (m) ,  ( m ) , 1286 ( m ) , 1 2 1 4 (m) cm'^. ^H  NMR  2.25  S:  ( 3 0 0 MHz)  CH2-CH-CH3),  J  much  9 0 % ) . R e c r y s t a l l i z a t i o n gave a w h i t e  MP: 88-92 °C ( l i t . 7 6  period  acidified  d i e t h y l e t h e r , washed w i t h d i l u t e HCl^^q) over  a  2.30  ( s , 3H,  ( s , 3H,  aromatic  7.1-6.8 aromatic  methyl),  (m, 3H, a r o m a t i c ) , methyl),  1.93  (m,  2.27  2H,  3.00 (m, I H ,  (m,  CH2),  2H,  CH2),  1.22  ( d , 3H,  = 8 H z , CH-CH3) ppm. MS ( E I ) m/e:  206 (M+, 5 5 ) , 146 ( 4 8 ) , 133  (100),  117  ( 1 9 ) , 105  ( 4 8 ) , 91 ( 4 4 ) , 77 ( 2 8 ) .  2,3-Dihydro-4,5,8-1rimethy1-1-naphthalenone In to  a  this  over  was  1  had  ml  added,  min.  dissolved. (0.282  500  The  The m i x t u r e  mole)  was  2-neck with  flask  was c o o l e d  diethyl washed  solution ether, with  was  to  i n several  washed  water  then with  again,  75  rose  d i s s o l v e d , t h e r e a c t i o n was s t i r r e d  The  placed  stirring,  temperature  added  was  poured water,  (61)^6  g  to  170  100 g o f 8 5 % H3PO4 a n d  °C  of  -200  °C  and  and  58  g  portions. at  After  140  over  anhydrous  °C  neutralized  of  with  min  extracted sat.  d r i e d o v e r MgSO^, a n d f i l t e r e d .  solid  acid  a l l the  for 5  ice,  the  P2*-'5  60 acid  more. with  NaHC03,  The s o l v e n t  was r e m o v e d t o g i v e 39.6 g o f a n o i l ( y i e l d 7 4 % ) . IR  (neat)  v^^^.:  2929  (s,  CH) ,  5:  7.17  (d,  1677  (s,  C=0) ,  1474  (m) ,  1263 (m) c m ' l . % (d,  NMR  (300  MHz)  I H , J = 8 Hz, a r o m a t i c )  aromatic 1.95  methyl),  2.32  (m, 2H, C H 2 ) , 1.25 MS  (50),  ( E I ) m/e:  3.28  (s,  (m,  3H,  I H , J = 8 Hz, a r o m a t i c ) ,  IH,  CH2-CH-CH3),  aromatic methyl),  188 (M+,  1 0 0 ) , 173 ( 9 0 ) , 160  (62),  ether  ketone  under 285  45  61  of  1.4  The r e a c t i o n min,  w i t h water,  (36  nitrogen  ml  Aldrich).  poured  was M  g,  0.19  added  cis/trans  A  small  mixture  portion  was  mole)  3H,  (m, 2H, C H 2 ) , ppm.  145  (61),  132  was into  warmed  of  to  in  62 to  a white give  mole,  gave  IR  ( K B r ) Ujua^: 3345 ( v s , OH), 2 9 4 1 ( v s , CH) , 1466  from  stirred  34  g  of  ( y i e l d 88%).  colorless  87-89 °C  °C  e t h e r , washed  solid  MP:  0  and  with diethyl solvent  diethyl  at  (0.4  temperature  of as  stirring  hexane  room  Removal  recrystallized  (lit.^^  with  i c e , extracted  compound  (62)  i n 100 m l a n h y d r o u s  dropwise  methyllithium  a n d d r i e d w i t h MgSO^.  a  812  (s,  117 ( 6 6 ) , 91 ( 3 9 ) .  To  for  2.20  ( d , 3H, J = 7 H z , a l i p h a t i c m e t h y l )  1,2.3,4-Tetrahydro-l,4,5,8-tetramethyl-l-naphthol  was  2.57  6.97  crystals.  93-95 ° C ) . ( s ) , 1124 ( s ) ,  ( s ) cra-1. ^H  NMR  aromatic), aromatic 2.25-1.96  (300 3.12  methyl), (m,  2H,  MHz,  cis/trans  (m, 2.30 CH2),  IH,  mixture)  5:  CH2-CH-CH3), (s,  1.95-1.65  3H, (m,  2H,  7.00-6.89 2.61  (m, (s,  2H, 3H,  aromatic  methyl),  CH2),  (s,  1.57  3H,  HO-C-CH3), 1.22 ( d , 3H, J = 5 H z , CH-CH3) ppm. MS  ( E I ) m/e:  Anal,  calcd.  204 (M+, 1 1 ) , 189 ( 1 0 0 ) ,  1 7 1 ( 5 4 ) , 156 ( 2 7 ) .  f o r C14H20O: C, 8 2 . 3 0 ; H, 9.87. F o u n d : C, 8 2 . 6 2 ;  H, 9.82.  I , 2-D i h y d r o - 1 , 4 , 5 , 8 -1 e t r a m e t h y I n a p h t h a l e n e The  crude  dissolved of  i n  cone  alcohol  200  HCl^^q).  neutralized  ml  of  After  with  in  solvent.  the f i r s t IR  2.28  This  (31  tetrahydrofuran stirring  for  17  g  of  h,  the  extracted  g e l using petroleum gave  0.15  mole)  was  a n d t o t h i s was a d d e d 20 m l 1  NaHC03,  g,  a  ether  reaction  with (30-60  colorless  was  ether °C)  and  as  the  o i l ( y i e l d 61%)  band.  (neat)  ^H NMR vinyl),  above  saturated  chromatographed on s i l i c a eluting  from  (63)^6  3.01  v^^^^:  ( 3 0 0 MHz) (m,  IH,  ( s , 3H, a r o m a t i c  2963  ( s , CH) , 1456 ( s ) , 813 (m) cm-^.  5:  5.89  ( s , 2H,  CH2-CH-CH3),  methyl),  2.41  2.19 (m,  aromatic), ( s , 3H,  3H,  vinyl  5.77  (m,  aromatic  methyl),  IH,  methyl), 2.10-2.00  (m, 2H, C H 2 ) , 1.06 ( d , 3H, J = 7 H z , CH-CH3) ppm. MS ( E I ) m/e:  185 (M+, 4 3 ) , 171 ( 1 0 0 ) ,  1,4,5,8-Tetramethylnaphthalene The  alkene  63  (10  155 ( 6 0 ) , 141 ( 2 6 ) .  (64)^6  g,  54 mmoles) was p l a c e d i n a 2 - n e c k  f i t t e d w i t h a condenser and a n i t r o g e n i n l e t . 10% to of  To t h i s was a d d e d 2  p a l l a d i u m on a c t i v a t e d c h a r c o a l ( A l d r i c h ) and t h e m i x t u r e 280 °C i n a s a n d b a t h nitrogen  f o r 5 h. D u r i n g  was f l u s h e d t h r o u g h  the  the i n l e t  reaction,  t o remove  a  g  of  heated to  slow  t h e H2(p-)  flask  stream evolved.  After  the r e a c t i o n ,  filtered, to  the sample  was  c o n c e n t r a t e d i n vacuo,  g i v e 1.7  1 2 8 - 1 3 0 °C  IR  (KBr)  ^H NMR 4 X methyl) MS  and  g of c o l o r l e s s needles  MP:  (lit.''^  131  2937 (m,  Un,ax:  (300MHz)  5:  dissolved  in  methylene  twice r e c r y s t a l l i z e d  (yield  chloride,  from  methanol  17%).  °C) .  CH) , 1593  7.09  (s,  (m) , 1463 4H,  (m) , 816  aromatic),  (s)  2.82  cm'^. (s,  12H,  ppm.  ( E I ) m/e:  184  (M-(-, 1 0 0 ) , 169  ( 8 6 ) , 153  (27).  Dimethyl  1,4-Dihydro-l,4,5,8-tetramethyl-l,4-ethenonaphthalene-2,3-  dicarboxylate  (47)  Tetramethylnaphthalene  64  (1.7  acetylenedicarboxylate  (0.9  ml,  (0.15  under  vacuum  and  g)  were  heated  at  m i x t u r e was hexanes of  sealed 180  °C  for  chromatographed  (1  :  9  v/v)  a  white  solid.  (yield  MP:  °C.  IR  (KBr)  Vj^^y.:  9.2  a  an  silica  and  Pyrex  explosion-proof using  as t h e e l u t i n g s o l v e n t . band from  The  dimethyl  hydroquinone  thick-walled  gel  the second  mmoles),  mmoles),  in  in  Recrystallization  c o l o r l e s s needles 126-127  7.3  h  on  t e t r a m e t h y l n a p h t h a l e n e , and  as  2  g,  diethyl  oven.  The  ether  and  first  b a n d was  the  product  was  methanol  tube  gave  518  1253  (s,  0.9  g  (47) mg  of  20%).  1728  (s,  C=0)  ,  1645  (m)  ,  1606  (m)  ,  C-0)  cm-1. ^H NMR 3.73 2.21  (s,  ( 3 0 0 MHz)  6H,  ( s , 6H,  2  x  S : 6.59  ester  ( s , 2H,  CH3),  2 X b r i d g e h e a d CH3)  2.54 ppm.  a r o m a t i c ) , 6.54 (s,  6H,  2  ( s , 2H, x  vinyl),  aromatic  CH3),  l ^ c NMR 146.53  (50  (CH),  (ester  130.57  CH3), 22.51 MS  H,  (C) ,  165.31  326  (C=0),  129.32  (M+,  (CH),  (CH3)  236  2 0 ) , 294  calcd.  (€ 2 7 0 0 ) , 281 for  151.50 53.41  (C),  146.64  (C),  (C b r i d g e h e a d ) ,  51.91  ppm. ( 4 3 ) , 266  f o r C20H22O4: 3 2 6 . 1 5 1 8 ,  (CH3CN):  Anal.  5:  ( C H 3 ) , 21.09  ( E I ) m/e:  mass c a l c u l a t e d UV  MHz)  (100).  Exact  F o u n d : C,  73.48;  f o u n d 326.1525.  (e 975)  C20H22O4: C,  ( 9 8 ) , 207  nm.  7 3 . 6 0 ; H,  5.79.  5.73. The  structure  diffraction  of  analysis.  space group P 2 i / c ,  this  compound  was  supported  C r y s t a l d a t a i s as f o l l o w s :  a =  12.643(9)Â,  b  =  by  an  X-ray  C20H22O4, m o n o c l i n i c ,  9.288(1)Â,  fi = 105.595(5)°, V = 1 7 1 2 . 8 ( 5 )  3 , Z = 4, D,, = 1.265  c  =  15.153(9)Â,  g / m l , R = 0.037.  l-Deuterionaphthalene^^ Over  a  half  hour p e r i o d ,  1-bromonaphthalene  i n 100 m l o f a n h y d r o u s d i e t h y l e t h e r was (8.0  g,  0.20  mole)  r e s u l t i n g m i x t u r e was 0.05 was  mole) stirred  acidified  was  the  80  refluxed  added  i c e . The three  solvent  ml  at  solution times  Recrystallization first  room  to  79-80 °C  the  magnesium diethyl  give  addition,  temperature  diluted  water,  with  dried 24  g  and 200  over  (lit.^^  80 ° C ) .  mole)  turnings  ether. (10  the  quenched ml  MgS04,  gave  The ml,  reaction  of  with  diethyl filtered,  of a light yellow  from methanol then from hexanes  plates. MP:  anhydrous  After  was  with  evaporated  of  to  f o r 1 h a n d c o o l e d t o 0 °C. D2O  dropwise.  f o r 0.5 h f u r t h e r  e t h e r , washed and  in  added  ( 4 0 g, 0.194  solid.  colorless  IR 807  (KBr)  3055  Uniax^  (m,  1590  (m) , 1500 (m) , 1376 (m) ,  ( m ) , 777 ( v s ) cm-1. ^H NMR  ( 3 0 0 M H z ) 5: 7.9-7.7  7.5-7.3 (m, 4H, H2+H3+H6-I-H7) MS  Mixture  ( E I ) m/e:  The  +  0.99D,  H1+H4+H5+H8),  ppm.  129 (M+, 1 0 0 ) , 103 ( 7 ) .  (29-D)  earlier^  (47 m m o l e s ) , 3.0 Aldrich),  except  ml  of  and  0.5  that  dimethyl g  of  t h i c k w a l l e d s e a l e d tube. A f t e r prisms  3.OIH  p r o c e d u r e was t h e same a s f o r t h e n o n - d e u t e r a t e d  described  from  (m,  o f Dimethyl 1 and 5 - D e u t e r i o - l , 4 - d i h y d r o - l , 4 - e t h e n o n a p h t h a l e n e -  2,3-dicarboxylate  (yield MP:  6.0  g  of  preparation  1-deuterionaphthalene  a c e t y l e n e d i c a r b o x y l a t e (24 hydroquinone  mmoles,  w e r e p l a c e d i n one P y r e x  recrystallization,  1.8  g  of  colorless  14%) were o b t a i n e d .  105-106 °C.  IR  (KBr)  v^^y.:  1732  ^H  NMR  (300  MHz)  ( s ) , 1714  7.02-6.90 (m, 4.00H, Hg-HHy + J  CH) ,  5:  ( s ) , 1643  7.35-7.20 vinyl),  (m) , 1238  (m,  1.59H  5.30-5.20  (s)  +  (dd,  cm'^.  0.41D, Hj-t-Hg) , 1.47H  +  0.53D,  = 4,3 H z , b r i d g e h e a d ) , 3.78 ( s , 6.61H, 2 x m e t h y l ) ppm. MS  153  271  (M+,  51),  ( 1 0 0 ) , 129 ( 5 6 ) . E x a c t  mass  calculated  found  ( E I ) m/e:  243  ( 1 3 ) , 211  ( 7 7 ) , 184 ( 6 3 ) ,  f o r Ci6H2^304D:  271.0955.  271.0964.  Mixture  of  dicarboxylic The  1 Acid  and  5-Deuterio-l,4-dihydro-l,4-ethenonaphthalene-2,3-  (40-D)  procedure  was  the  same  as  for  the  non-deuterated  preparation  described  earlier  i n 90 m l o f e t h a n o l a n d After  workup,  5.7  Recrystallization MP:  g  ^H 1.49H 5.25  white  5:  in  of  250  solid  Hg),  m/e:  (br (s)  29-D ml  was  was  water  obtained  dissolved was  used.  ( y i e l d 92%).  (M+,  OH),  1694  (m,  s, 1.18H, OH), 4.00H,  Hz, b r i d g e h e a d )  1 9 ) , 199  (s) ,  1618  (s) ,  7.35-7.25  (m,  cm'^. (br  7.05-6.90  243  m,  11.65  + 0.45D, J = 4,3  (EI)  g  gave p r i s m s .  ( s ) , 1240  MHz)  + 0.51D, H5 +  MS  NaOH  3200-2200  (400  ( d d , 1.55H  6.9  °C.  ( s ) , 1280  NMR  a  of  from a c e t o n i t r i l e  208-209  ( v s ) , 1467  g  of  IR ( K B r ) 1567  75  except  Hg  +  H7  +  vinyl),  ppm.  ( 5 7 ) , 154  ( 1 0 0 ) , 129  (33). Exact  mass c a l c u l a t e d f o r C14H9O4D: 2 4 3 . 0 6 4 1 , f o u n d 2 4 3 . 0 6 4 1 .  Mixture  of  1  and  5-Deuterio-l,4-dihydro-l,4-ethenonaphthalene-  2,3-dicarboxylic Anhydride The  same  (41-D)  procedure  used  was u s e d h e r e e x c e p t t h a t 4.8 m e t h y l e n e c h l o r i d e was Recrystallization of  for  g o f 40-D  the  non-deuterated  ( 2 0 mmoles) i n  135  r e a c t e d w i t h 4.0 m l o f o x a l y l c h l o r i d e  preparation ml  of  dry  (0.48 mole)  f r o m a 1:4 m i x t u r e o f b e n z e n e a n d h e x a n e s g a v e  3.4  g  l i g h t yellow needles ( y i e l d 76%). MP:  128-129  °C.  I R ( K B r ) v^ax-  ^^^^  ^H  MHz)  NMR  (400  7.15-7.00 (m, 4.00H, H5  +  J  ppm.  = 4,3  Hz, b r i d g e h e a d ) MS  (EI)  m/e:  225  - ^771  ( s , C=0) , 870  6:  7.40-7.30  H7  +  (M+,  vinyl),  56),  181  (m, 5.29  (m)  cm'^.  1 . 4 4 H + 0 . 5 6 D , H5 + H g ) , (dd,  (41),  153  1.32H  +  0.68D,  ( 1 0 0 ) , 129 ( 4 1 ) .  E x a c t mass c a l c u l a t e d f o r Cj^4H703D: 2 2 5 . 0 5 3 6 , f o u n d  M i x t u r e o f 1,4,5, a n d  225.0534.  8-Deuterio-l,4-dihydro-l,4-ethenonaphthalene-2,3-  d i c a r b o x y l i c A c i d Monomethyl E s t e r (58-D) The 58 e x c e p t dry  procedure t h a t 1.00  methanol. IR  (s),  1440  The  Uj^^x^  ( v s ) , 712  g  41-D  3400-2400  (m)  dissolved  in  30  ml  of  (vs),  1636  (100%). ( b r s, OH),  1718  cm'^.  7.39-7.29  + H7  was  (m,  + vinyl),  1.64H  5.90  ( d , 0.75H + 0.25D, J = 5  +  0.36D,  H5  +  Eg),  ( d , 0.82H + 0.18D, J = 5  Hz,  Hz,  (s,  bridgehead),  3.99  (EI)  m/e:  257  (34). Exact  (M+,  6),  225  mass  calculated  (10), for  213  (18),  C3^5Hxi04D:  181  (19),  257.0798,  257.0796.  Mixture  of  Methyl  1,4,5,  and  ethenonaphthalene-3-carboxylate The except  procedure  that  chloride, and  same a s f o r t h e p r e p a r a t i o n o f compound  ppm.  ( 1 0 0 ) , 129  found  film)  4.00H, Hg  3.24H, m e t h y l )  153  1.16  ( 4 0 0 M H z ) 5:  b r i d g e h e a d ) , 5.60  MS  y i e l d was  ( s ) , 1278  7.02-6.92 (m,  the  g of anhydride  (liquid  ^H NMR  was  3 ml  1.16  was g  w h i t e s o l i d w e i g h e d 566 MP: IR  (43-D)  t h e same a s f o r t h e n o n - d e u t e r a t e d p r e p a r a t i o n ,  of  58-D  of oxalyl chloride  a p p r o x i m a t e l y one  127-128  8-Deuterio-2-benzoyl-l,4-dihydro-l,4-  ( 4 . 5 1 mmoles) i n 50 ml o f d r y (34.4  m m o l e s ) , 600  molar e q u i v a l e n t of AICI3 mg  (yield  was  ml  of dry  used;  the  methylene benzene, resulting  40%).  °C.  ( K B r ) Umax^ ^712  (s,  ester  C=0),  1667  (s,  benzoyl  C=0),  1242  ( s , C - 0 ) , 702 ( s ) cm"^. NMR  and v i n y l ) ,  (400  MHz)  5:  7.60-6.95  5.54 ( d , 0 . 6 7 H + 0 . 3 3 D ,  J =  6  (m, Hz,  10.80H + 0.20D, bridgehead),  aromatic 5.03  (d,  0.67H + 0.33D, J = 6 H z , b r i d g e h e a d ) , 3.40 ( s , 3.00H, m e t h y l ) ppm. MS 77  ( E l ) m/e:  (23). Exact  317.1153.  mass  317  (M+,  calculated  4),  285  for  ( 6 ) , 129 C21H15O3D:  ( 1 1 ) , 105 ( 1 0 0 ) , 317.1162,  found  II.  A.  PHOTOCHEMISTRY OF  SUBSTRATES  Dimethyl 1,4-Dihydro-l,4-ethenonaphthalene-2,3-dicarboxylate  Direct Solution  Photolysis^^•  A n a l y t i c a l p h o t o l y s e s (A > 290 methanol, which  and  100  acetonitrile.  ml  of  benzene  directly  and methanol dicarboxylate  1025  (s,  =  to give  (KBr)  12 6H,  Hz,  white  performed  in  benzene,  product independent mg  ( A > 290  monitored three  by  of  GC.  of  (1.9  The  dimethyl  mmole)  i n an immersion reaction  t i m e s f r o m a 2:1  needles  solvent.  o f 29 nm)  (DB-1)  in well  mixture  m i x t u r e o f hexanes  benzocyclooctene-7,8-  (29d)^'^.  IR  ^H NMR J  were  r e a c t i o n s w e r e m o n i t o r e d b y GC  photolyzed  recrystallized  77-78 °C  800  was  conversion,  MP:  (m),  nm)  a p r e p a r a t i v e r u n , a s o l u t i o n o f 500  setup to complete was  The  s h o w e d t h e f o r m a t i o n o f one In  (29)  (lit.^^  77.0-77.5  Uniaj^: 1724  (m)  °C).  ( s , C=0) , 1435  (m) , 1260  ( s , C-0),  1149  (m) ,  cm'^.  ( 3 0 0 M H z ) 6: benzylic  2 X methyl)  7.30-7.00 (m,  vinyl),  6.20  4H,  aromatic),  ( d , 2H,  J = 12 Hz,  6.77  (d,  2H,  ^-vinyl),  3.75  ppm.  MS  ( E I ) m/e:  270  UV  (CH3CN) \^^^:  (M+,  1 1 ) , 238  (14),  210  (77),  179  (32),  152  (100).  Anal. H,  5.24.  calcd.  284 for  sh  (e 1820)  C16H14O4:  C,  nm. 7 1 . 1 0 ; H,  5.22.  F o u n d : C,  71.19;  Benzophenone-Sens i t i z e d P h o t o l y s i s On  an  analytical  scale,  photolysis  of  an  mass  ratio  of  glass  filter  (A > 330 nm) g a v e o n l y one p r o d u c t b y GC  compound 29 t o b e n z o p h e n o n e i n b e n z e n e t h r o u g h a  A s o l u t i o n o f 50 mg o f compound 29 benzophenone  (2.2  to  by  GC u n t i l no s t a r t i n g  g i v e 39 mg o f t h e p r o d u c t  identified  as  dimethyl  2a,6c-dicarboxylate  J  IR  ( n e a t ) v^^^:  %  NMR  152  >  thick  Acetone-Sensitized  GC  show  to  270  (m,  4H,  (M+,  37),  238  reaction  was  and chromatographed o i l (yield  aromatic),  78%),  5.82  IH,  ppm.  ( 9 4 ) , 183 ( 9 0 ) ,  270.0892, f o u n d  270.0892.  >  29  290  nm).  performed  i n  reaction  was  The  1:1,  decomposes  conversion  increased,  d e c o m p o s e s s l o w l y , a n d a new p e a k  arose  time  29b.  compound  acetone  using  monitored  by  w i t h r e t e n t i o n times corresponding to ratio  to  (dd,  ( d , I H , J = 3 H z , H6b),  ( 1 4 ) , 210  analytically  2 major photoproducts  corresponding  was  278 (e 1 1 0 0 ) nm.  P h o t o l y s i s o f Compound  s l e e v e (A  as  was p h o t o l y z e d  The  compounds 29a a n d 29e. A t l o w c o n v e r s i o n t h e i r but  of  cm'^.  ( d , I H , J = 5 H z , H 2 ) , 4.49  photolysis  filter  g  2b,6b-dihydrobenzo[a]cyclopropa[cd]pentalene-  1730 ( s , C=0)  (CH3CN) \^^^:  a Pyrex  0.40  3.85 ( s , 3H, m e t h y l ) , 3.70 ( s , 3H, m e t h y l )  ( E I ) m/e:  The  nm).  colorless  ( 1 0 0 ) . E x a c t mass c a l c u l a t e d f o r Ci^Hii^O^: UV  and  o f acetone  330  uranium  (DB-1).  mmole)  m a t e r i a l remained  a  ( 3 0 0 MHz) 6: 7.5-7.1  ( s , I H , H2b), MS  as  (A  1:1  (29a).  = 5,3 H z , H i ) , 5.36  4.48  (0.18  mmole) i n a 10 m l p h o t o t u b e  w i t h a medium p r e s s u r e m e r c u r y lamp monitored  approximately  29e in  the  Compounds  GC 29e  was  with and  approximately quickly, a  29a  retention 29b w i l l  be  characterized  later.  On a p r e p a r a t i v e of  acetone  conversion.  was p h o t o l y z e d GC  diethyl  ether  mixture  of  Chromatography 93:7 29e  of  comparison  (A > 290 nm)  these of  the  29e,  a n d 29b  i n a ratio  with  pet.  ether  ( v / v ) g a v e two b a n d s . The  first  was  and  29b,  eluting  ( 1 . 5 0 g, 5.6 m m o l e s ) i n 425  followed  compounds  was  mixtures  by  0.96  g o f 29a  confirmed  to t h e i r  ml  i n an immersion w e l l t o complete  showed p h o t o p r o d u c t s 29a,  respectively.  identity  s c a l e , compound 29  full  by  65:25:9  ( 3 0 - 6 0 °C) an  and  inseparable  ( y i e l d 5 4 % ) . The  NMR  spectroscopic  characterizations, described  later.  Solid  State P h o t o l y s i s Crystals of  Pyrex  glass  compound  29  were  photolyzed  f o r 2, 5, a n d 9 h t o a f f o r d one p r o d u c t ,  (COT) 29c  a t 30%, 15%, and 25% c o n v e r s i o n  crystals  turned  and  COT  1 15%  h  yellow  and  were  29c w e r e i n s e p a r a b l e b y Laser  also  on  GC.  The  >  260  nm),  than the other  Compound 29  i n a n NMR  surface melting.  at  benzene a  i n a c e t o n i t r i l e was  two r e a c t i o n s .  and  analytically  and  g a v e one m a j o r p r o d u c t reaction  the  tube GC  for  showed  a  29c.  Compound 29a was p h o t o l y z e d (A  the surface.  o f the c r y s t a l s  Photochemical I n t e r c o n v e r s i o n of Compounds 29a  acetonitrile  cyclooctatetraene  TLC.  r e s u l t e d i n y e l l o w i n g and s l i g h t to product  through  r e s p e c t i v e l y . In a l l cases,  sticky  p h o t o l y s i s (A = 337 nm)  conversion  photolyses  analytically  (A  maximum  29b  i n acetone >  260  (A > 290 nm).  conversion  nm),  A l l three of  f o u n d t o p r o c e e d much more  52%  by  slowly  In 200  ml  in  a preparative of  an  benzene  immersion  band  (1  was  for  using  59  13  IR  (KBr) NMR  J  =  3  H2b),  (s,  I H , J = 8,3  84  Hz,  (s,  H2a)  a  by  GC,  270  4H,  Hg^),  3.71  (M+,  analytical  c a l i b r a t e d by  internal  the  two  It  t o 29b were  55),  ratio  (A  of 7 ± 1  e s t a b l i s h a 29a  >  scale  was  3H,  210  an  solvent.  (d,  ether  The  first  9%).  6.15 IH,  (d, J  methyl),  (62),  =  IH, 8  Hz,  3.43  (dd,  ( 4 7 ) , 152  (100),  was  260  : 3 + 1.^^ t o 29b  too  nm) c)  ratio  analytical  270.0892, found  photolyses.  a)  in  fast  i n acetone of 8  scale,  compound 29b,  times  to  (A  260  determined  d e t e c t o r i s 1.6  establish  >  investigated  (n-C]^gH38)  acetonitrile  to  thirteen  was  270.0885.  R a t i o s were  octadecane  Compound 29a,  photolyzed:  183  o f the r e a c t i o n  (A an  and >  mixtures  260  nm)  equilibrium,  establish nm)  times  a 29a  three  but b)  to  29b  times  to  : 2.  A c e t o n e - S e n s i t i z e d P h o t o l y s i s o f Compound On  petroleum  aromatic),  c a l c u l a t e d t h a t t h e GC  t h e n 29a.  compound d e c o m p o s i t i o n benzene  and  3.89  (s,  co-injections with  standard.  more s e n s i t i v e  subsequently  was  nm)  PPm.  m/e:  of  sample  as a c o l o r l e s s o i l ( y i e l d  (m,  photostationary state ratio  series  in  cm'^.  IH,  methyl),  mmoles) (A > 260  eluting  ( 4 2 ) . E x a c t mass c a l c u l a t e d f o r Ci(^Eii^Oi^:  by  in  (29b)  7.4-7.1  4.69  2.4  2b,6b-dihydrobenzo[a]cyclopropa[cd]-  ( s , C=0)  S:  3H,  (EI)  The  of  1^19  vinyl),  3.72  the  g,  a Corex f i l t e r  acetate  of dimethyl  (300 MHz)  Hz,  MS  u^ax^  The  as  pentalene-1,6c(2aH)-dicarboxylate  (0.64  through  ethyl  solution  mg  29a  h.  an  : 19 v / v )  contained  compound  irradiated  well  chromatographed ( 3 0 - 6 0 °C)  run,  29c  solutions  of  29c  in  acetonitrile.  benzene, and acetone were p h o t o l y z e d  (A > 290  29e  GC  was  the  conversions  only  peak  seen  in  200  an  immersion  ml  of  acetone  well  (subsequently  ether  eluent.  This  irradiated  system.  and  The  and low  boiling 71  Pyrex  was  monitored  reaction  then  afforded  ( K B r ) v^^y.: NMR  =  3 =  3.65  Hz, 6  (300  vinyl),  Hz,  H2a)>  chromatographed petrole\im  mg  of  152  (EI)  (A  on  ether  mmole)  >  290) i n  by  GC  to  silica  (1:3  dimethyl  0.37  v/v)  using  as  the  2b,6b-dihydrobenzo[a](29e)  as  a  colorless  found  MHz)  8:  4.51  (d,  (100).  29c,  IH,  (m,  J  =  4H, a r o m a t i c ) , 6.58 3  Hz,  I H , J = 6 H z , H2b)>  Hgb)>  3.84  3.70  ( s , 3H,  (d, IH, (d,  IH,  methyl),  (M+,  Exact  34), mass  238  (19),  calculated  210  for  (92),  183  (58),  C16H14O4: 2 7 0 . 0 8 9 2 ,  270.0889.  Compound 2 9 c  by  7.4-7.1  (d,  270  Detection o f Cyclobutene  was  cm'^.  ppm.  m/e:  ( 7 8 ) , 43  1718 ( s , C=0)  3.74  ( s , 3H, m e t h y l ) MS  photolyzed: GC  and 29d,  compound to  compound  ( y i e l d 71%). IR  J  h;  characterized) at  through  cyclopropa[cd]pentalene-2,6c(2aH)-dicarboxylate  J  10  c y c l o o c t a t e t r a e n e 2 9 c ( 1 0 0 mg,  was  conversion  diethyl  oil  for  o f 15%, 22%, and 100% r e s p e c t i v e l y .  On a p r e p a r a t i v e s c a l e ,  complete  on  nm)  (6  a)  29d  mg,  in  analyzed and  29d  by  0.022  acetone-dg NMR  (300  mmole) (A  >  MHz).  29e w e r e d e t e c t e d i n a r a t i o was  thermally  cyclooctatetraene  29c  on  unstable  and  dissolved 290  nm)  Signals o f 74  in to  an 10%  NMR  tube  conversion  corresponding : 14  readily  to  : 12. T h i s  third  reverted  back  GC; b ) i n d e u t e r i o c h l o r o f o r m (A > 330  nm)  for  3 d a y s t o show no c o n v e r s i o n o n GC, b u t NMR  mixture  of  29c  to  mixture, dimethyl was  o f 75  : 15  shows a 83  : 17  t h e c y c l o b u t e n e d e r i v a t i v e 2 9 d . F r o m t h e NMR  of the  cyclobuta[a]naphthalene-2,2a(8bH)-dicarboxylate  (29d)  characterized;  ratio  ( 3 0 0 MHz)  c)  in  b e n z e n e - d g (A > 330 nm)  : 9 c h a r a c t e r i z e d b y •'-H NMR  of  t o a 29c  the  : 2 9 d : 29e  mixture  as  well.  S p e c t r o s c o p i c d a t a f o r 29d a r e d e s c r i b e d below. ^H  NMR  (400  w i t h 2 9 c ) , 7.72 J  =  10  methyl)  Hz,  CDCI3) 5: 7.3-7.0 (m, 4H, a r o m a t i c  ( s , I H , Hj^) , 6.47 H 3 ) , 4.23  ( d , I H , J = 10 H z , H4) ,  ( s , I H , H g b ) , 3.78  overlapping  6.22  ( s , 3H, m e t h y l ) ,  (d,  3.76  IH,  ( s , 3H,  ppm. •'"H NMR  reported) 4.04  MHz,  5:  (300  MHz,  6.40  ( d , I H , J = 10 Hz, H 4 ) , 6.26  ( s , I H , Hgb)  benzene-dg,  only  non-overlapping  peaks  are  ( d , I H , J = 10 H z , H 3 ) ,  ppm.  B. 1 , 4 - D i h y d r o - l , 4 - e t h e n o n a p h t h a l e n e - 2 , 3 - d i c a r b o x y l i c  A c i d (40)  Direct Solution Photolysis Analytical conducted and  DMSO-dg  This as  in  NMR  (6  showed  tubes.  mg), the  the only product On  was  photolyses  a  phototubes, reaction allowed  mixture to  formation  Pyrex were  for of  >  290  the was  scale, nm)  1.5  40c  solution  h,  concentrated  crystallize.  Clear  brown  in  and  a rods  nm)  CDCI3  analyzed  (60  were (3  by  mg) NMR.  characterized)  mg,  acetate,  bright to  290  respectively.  40  ethyl  was  >  (subsequently  diacid in  (A  dissolved  a t 5 0 % a n d 5% c o n v e r s i o n  (A  until  Samples  photolyzed  preparative  photolyzed  through  using  yellow  volume were  0.25  (1.75  3  mmole) x h) .  10 m l The  o f 5 m l a t 60 °C a n d filtered  (18  mg)  and  identified  as  benzocyclooctene-7,8-dicarboxylic  anhydride  (41d)60 ( y i e l d 3 2 % ) . MP: 2 1 0 - 2 1 2 °C. IR  ( K B r ) v^^^: 1767 ( s , C=0) , 1 2 6 3 ( s , C - 0 ) , 713 ( s ) cm''^. NMR  6.99 6.19  ( d , 2H,  6.19  J  CDCI3)  5:  7.35-7.25  = 12 H z , b e n z y l i c v i n y l ) ,  (m,  6.97-6.91  2H,  aromatic),  (m, 2H, a r o m a t i c ) ,  ( d , 2H, J = 12 H z , / 9 - v i n y l ) ppm. ^H  7.13  ( 4 0 0 MHz,  NMR  ( 3 0 0 MHz,  ( d , 2H,  J  DMSO-dg)  5:  7.36-7.28  = 12 H z , b e n z y l i c v i n y l ) ,  (m,  7.05-6.80  2H,  aromatic),  (m, 2H, a r o m a t i c ) ,  ( d , 2H, J = 12 H z , / 3 - v i n y l ) ppm. MS ( E I )  m/e:  224  (M+,  6 9 ) , 180  ( 4 2 ) , 152  (100),  76 ( 4 1 ) .  E x a c t mass c a l c u l a t e d f o r C i 4 H 8 0 3 : 2 2 4 . 0 4 7 4 , f o u n d 2 2 4 . 0 4 7 4 . Anal.  calcd.  f o r Ci4H803:  C,  7 5 . 0 0 ; H, 3.60. F o u n d : C, 7 4 . 9 5 ;  H, 3.56. The m o t h e r l i q u o r was l e f t formed.  This  dicarboxylic  was acid  MP: C r a c k s at  filtered  (40c) c r y s t a l s  stand  give  20  ( K B r ) Ujnax:  melting  and mg  clear  of  yellow  needles  benzocyclooctene-7,8-  ( y i e l d 33%).  and t u r n s orange a t  2 0 8 - 2 1 0 °C ( a n h y d r i d e IR  to  to  122-130  °C  (dehydration),  melts  point).  3100-2400  ( b r s , OH), 1 7 2 4 ( s , C=0) , 1624 (m) ,  1230 ( s ) cm-1. ^H NMR (m,  4H,  ( 4 0 0 MHz, DMSO-dg) 5:  aromatic),  6.72  12.95 ( b r s , 2H,  2  x  OH),  ( d , 2H, J = 11 H z , b e n z y l i c v i n y l ) ,  7.4-7.0 6.18 ( d ,  2H, J = 11 H z , / 3 - v i n y l ) ppm. MS ( E I ) m/e: 224 (M+ - H2O, 7 2 ) , 180 ( 3 0 ) , 152  (100),  84 ( 8 2 ) ,  66 ( 9 9 ) . MS (DCI-NH3) m/e: 243 (M+ + 1, 1 1 ) , 224 ( 1 0 0 ) ,  180 ( 4 7 ) , 152 ( 9 0 ) ,  85  (94).  Benzophenone-Sensitized Photolysis S a m p l e s o f d i a c i d 40 were  dissolved  (A > 330  nm).  and  shown  was  repeated  40c 40b  was  in  Two to  products  be  40a On  10  phototubes, to  conversion  complete  and  mixture  was  transferred  washed  with cone.  HCl,  anhydrous  diazomethane The  solution  20  min,  first  v/v)  was  was to  g a v e 11 mg  a 92  >  330  : 13).  :  8  10  :  diethyl  :  ether,  The  photolysis of  40b  to  s i g n a l s . Compounds  40  (120  and  78  component :  10.  extracted  remove  benzophenone),  with  diethyl  ether,  To  the  and  remaining  the  the water  second band c o n t a i n e d  o i l  solution from at  and  etheral  the with  40 mg  with  was  of a white  water,  added  5  with  Aldrich).  for  layer  until another  separated.  ether  in  and  solid  ml  excess  temperature  o f compounds 29a  of  reacidified  stirred  diethyl  by  reaction  Diazald,  room  five  w i t h NaOH^^q).  treated  was  : 1 mixture  0.50  ratio  The  washed  reaction  eluting  mg,  monitored  (to  dropwise  of a 3  conversion  ratio  final  2  added  gel,  nm)  The  (prepared  with  photolyzed  70%  87  mg)  d i s s o l v e d with acetone i n  ether  yellow;  silica  was  (A  ether  diethyl  quenched  b a n d . The  mg)  evaporated.  stayed  C h r o m a t o g r a p h y on  NMR  extracted  diazomethane  (ratio  at  o f compound  conversion.  ether  diethyl in  the  ( 1 : 9  by  diethyl  d r i e d o v e r MgS04 a n d of  40a  NMR,  30  later.  (900  40b,  with  and  (ca.  o f a c e t o n e - d g and by  ( 1 9 % ) , and  photolyzed  40a  benzophenone  i n t e g r a t i o n o f t h e e x p a n d e d NMR  benzophenone  almost  40c,  detected  a preparative scale, a mixture  and  40,  were  were c h a r a c t e r i z e d  mmole) ml  and  w i t h 1 ml  compounds 40b  at lower  mg)  phototube  d e t e r m i n e d by  and  NMR  a  (ca. 5  hexanes  29c  (yield  in  the  30%).  Recrystallization characterized  from  as  hexanes  dimethyl  rods  which  were  (29f)^*^.  MP: 86-87 °C ( l i t . ^  86.5-87.0 ° C ) .  IR  (m, CH) , 1729 ( s , C=0) , 1 2 7 3 ( s , C-0) cm"^.  ( K B r ) Ujnax^ 2927  ^H  NMR  ( 4 0 0 MHz)  5:  7.75-7.10 (m, 4H, a r o m a t i c ) , 4.23 ( d ,  = 6 H z , H g b ) , 3.73 ( s , 3H, m e t h y l ) ,  IH,  colorless  2a,2b,6b,6c-tetrahydrobenzo[a]cyclopropa-  [cd]pentalene-l,2-dicarboxylate  J  gave  J  =  6,6,6  3.71 ( s , 3H,  methyl),  IH,  3.50 ( d d d ,  H z , H g c ) , 3.29 ( d d , I H , J = 6,6 H z , H 2 b ) , 3.00 ( d d , I H ,  J = 6,6 H z , H2a) Ppm. MS ( E I ) m/e: 152  270  (M+,  3 2 ) , 238  ( 4 5 ) , 210  (100),  183 ( 4 8 ) ,  (100). Anal.  calcd.  f o r C16H14O4:  C, 7 1 . 1 0 ; H, 5.22. F o u n d : C, 7 1 . 2 5 ;  H, 5.27.  Solid  State Photolysis C r y s t a l s o f 40 w e r e p h o t o l y z e d  and  15  b y NMR  h.  These  crystals  (A > 290 nm) i n NMR t u b e s  Hydrolysis o f Benzosemibullvalene  photoproducts.  29f  Compound 2 9 f ( 2 6 mg, 9.6 x 1 0 " ^ m o l e ) was s t i r r e d f o r 10  4 ml water. water, with 18  ether, of  and  to  this  mixture  i n 0.5  with dried  a  white  diethyl with  of  t o 10  ml  with  e t h e r , a c i d i f i e d w i t h cone. H C l , e x t r a c t e d  MgS04,  solid  ml  was a d d e d 0.2 g o f NaOH i n  The r e a c t i o n was r e f l u x e d f o r 35 m i n , d i l u t e d  washed  mg  min  h  turned yellow with s l i g h t melting. Analysis  ( 4 0 0 MHz, DMSO-dg) showed no  ethanol  for 4  filtered,  (yield  77%) .  and This  evaporated was  2a,2b,6b,6c - t e t r a h y d r o b e n z o [ a ] c y c l o p r o p a [ c d ] p e n t a l e n e - 1 ,  to  afford  characterized  as  2-dicarboxylic  Acid  (40b). MP: > 300 °C ( d e c o m p o s e s s l o w l y a t a p p r o x . 150 ° C ) . IR  1567  ( K B r ) Ujnax^  J  ( b r v s , OH), 1699 ( s , C=0) , 1 6 0 1 ( s ) ,  ( s ) , 1 4 8 4 ( s ) , 1 2 6 3 ( s ) cm"^. ^H NMR  (d,  3200-2200  IH,  J  5:  ( 4 0 0 M H z , CDCI3) =  6  Hz,  Hgb),  7.25-7.05  3.50-3.38  (m,  4H,  aromatic),  4.46  (m, 2H, Hgb + Hg^), 3.33 ( d d , I H ,  = 6,6 H z , H 2 a ) Ppm. ^H NMR  (m, 6,6,6  4H,  ( 4 0 0 MHz, DMSO-dg) 5: 9.4 ( b r s , 2H,  aromatic),  4.20  (d, IH,  J  2  x  = 6 H z , Hgb).  OH),  7.50-7.05  3.46 ( d d d , I H , J =  H z , Hgc), 3.34 ( d d , I H , J = 6 H z , H 2 b ) , 3.06 ( d d , I H , J =  6,6  Hz,  H2a) ppm. MS  ( E I ) m/e:  242  c a l c u l a t e d f o r Cii^BiQOi^:  (M+,  1 6 ) , 224  Compound 3 ( 7 3 0 mg, and  to  ether,  29a  2.7  mmoles)  was  40  min.  acidified  The  cooled  mg o f a w h i t e  gave w h i t e  dissolved  solution  in  15  ml  solid  crystals,  was  washed  w i t h cone. H C l , e x t r a c t e d w i t h d i e t h y l  w a s h e d w i t h w a t e r , d r i e d o v e r MgS04, f i l t e r e d , 402  mass  of  t h i s was a d d e d 5.6 g o f NaOH i n 100 m l o f w a t e r a n d t h e  solution refluxed for diethyl  Exact  242.0579, f o u n d 242.0588.  Hydrolysis o f Benzosemibullvalene  ethanol  ( 5 5 ) , 152 ( 1 0 0 ) .  (yield  evaporated  61%). R e c r y s t a l l i z a t i o n from  characterized  [cd]pentalene-2a,6c-dicarboxylic  and  as  acid  with ether,  to  give  acetonitrile  2b,6b-dihydrobenzo[a]cyclopropa-  (40a).  MP: 1 7 8 - 1 8 1 °C. IR (m),  ( K B r ) Ujuax^  3200-2400  ( b r s,  OH),  1697  ( s , C=0) ,  1445  1299 (m) cm'^. ^H NMR  ( 4 0 0 MHz, CDCI3)  5:  10.3-9.8  ( b r s,  2H,  OH),  7.5-7.1  (m,  4H,  aromatic),  5.84  (dd, IH,  J  J = 5 H z , H 2 ) , 4.56 ( s , I H , H 2 b ) , 4.55 partial  =  5,3  Hz,  (d, IH,  J  H^),  =  3  5.40 ( d ,  Hz,  Hg^  IH,  with  o v e r l a p t o H2b) PPm. ^H  NMR  ( 2 0 0 MHz,  acetone-dg)  5:  11.6-11.0  7.6-7.1 (m, 4H, a r o m a t i c ) , 5.85 ( d d , I H , J =  5,3  ( b r s,  Hz,  H^),  2H, OH),  5.40 ( d ,  I H , J = 5 H z , H 2 ) , 4.50 ( d , I H , J = 3 H z , H g b ) , 4.40 ( s , I H , Hgb) Ppm. ^H  NMR  ( 4 0 0 MHz,  (m, 4H, a r o m a t i c ) ,  5.78  S:  DMSO-dg) (dd, IH,  J  1 3 . 1 - 1 2 . 3 ( b r s , OH), 7.55-7.10 =  5,3  Hz,  H^),  5.30  ( d , IH,  J = 5 H z , H 2 ) , 4.35 ( d , 3H, J = 3 H z , H g b ) . 4.24 ( s , I H , Hgb) Ppm. MS ( E I ) m/e: MS  ( n o M+ p e a k ) 198 ( 7 ) , 196 ( 8 ) , 152 ( 2 0 ) , 78 ( 1 0 0 ) .  (DCI-NH3)  198 ( 1 0 0 ) ,  m/e: 260 (M + NH4+, 1 2 ) , 243 (M + 1, 4 3 ) , 225 ( 1 9 ) ,  153 ( 7 8 ) .  Anal,  calcd.  f o r C14H10O4:  C, 6 9 . 4 2 ; H,  4.16.  Found:  C,  69.48;  H, 4.15.  DeuteriTim L a b e l l i n g Crystals of ethyl  and  until  the product  ethyl  of  acetate  continued  acetate  orange rods  Study 40-D  were the  (60  photolyzed solution  recrystallized and  mg, 0.25 mmole) i n t h r e e 10 m l p h o t o t u b e s  hexanes  (A  >  290  nm).  was  bright  yellow  from  in a  5  to  gave  :  The  reaction  (3h), then 1  was  evaporated  (v/v) solution  33 mg o f a n h y d r i d e  of  41d-D a s c l e a r  (yield 59%).  MP: 2 0 9 - 2 1 1 °C. ^H NMR H3), 6.19  ( 4 0 0 MHz, DMSO-dg) S :  7.15-6.95  7.40-7.25 (m, 2.05H, a r o m a t i c  (m, 3.12H + 0.88D, a r o m a t i c  (m, 2.00H, v i n y l  H^ + H4 a n d v i n y l  H2  +  H5 + H I Q ) .  Hg + H9) ppm.  In a t r i p l e t - s e n s i t i z e d  experiment,  compound  40-D  (25  mg,  0.10  nunole)  and  i n a n NMR  benzophenone  tube.  This  (10  was  were  photolyzed  d i r e c t l y a n a l y z e d b y NMR  G.  mg)  (A  dissolved >  330  ( s h o w n i n F i g u r e 3.10  w i t h 1.5 m l DMSO-dg  nm)  of  On  Anhydride  scale,  anhydride  41 was p h o t o l y z e d  i n benzene and e t h y l a c e t a t e t o g i v e t h r e e p r o d u c t s  Anhydride  41c,  an  41  (15  (A > 290 nm) NMR  and  (41)  (GC)  mg,  in  ratio  a  6.7  x  10'^  phototube  47  mole)  until  (A > 290  ( 4 1 a , 41b,  i n d e p e n d e n t o f s o l v e n t , whose r a t i o s h o w e v e r , v a r i e d w i t h  give  min  Photolysis  an a n a l y t i c a l  photolyzed  45  text).  1,4-Dihydro-l,4-ethenonaphthalene-2,3-dicarboxylic  Direct Solution  for  and  nm) 41c)  conversion.  i n 1 m l o f CDCI3  complete  was  conversion  to  ( 5 1 ) : 18 ( 1 3 ) : 24 ( 1 9 ) o f 4 1 a , 4 1 b ,  and  respectively. From a n a n a l y s i s o f t h e r e a c t i o n m i x t u r e s ,  be  4 1 a was  determined  to  2b,6b-dihydrobenzo[a]cyclopropa]cd]pentalene-2a,6c-dicarboxylic  anhydride. NMR with 4.57  41c),  ( 4 0 0 MHz, 5.90  CDCI3)  (dd,  I H , J = 6,3  ( d , I H , J = 3 H z , H g b ) , 4.45 GC-MS (DB-1, E I ) m/e:  126 found  5: 7.5-7.0 (m,  (100),  76  (72).  Exact  224  Hz, Hj^) , 5.44  ( s , I H , H2b) (M+,  mass  4H,  7 3 ) , 198 calculated  aromatic  overlapping  ( d , I H , J = 6 H z , H2) ,  Ppm. ( 8 8 ) , 180 for  ( 7 0 ) , 154  C14H8O3:  (91),  224.0474,  224.0465. Compound 41b was  2,3-dicarboxylic ^H  NMR  identified  from  the  mixture  as  naphthalene-  anhydride^^ (400  MHz,  CDCI3)  S:  8.57  (s,  2H,  H^ a n d H 4 ) ,  8.16  2H, H5 a n d Hg), 7.82 (m, 2H, Hg a n d H7) ppm.  (m,  GC-MS 98  (DB-1,  E I ) m/e:  198  (M+,  9 0 ) , 154  ( 9 1 ) , 126  (100),  ( 6 8 ) , 87 ( 7 0 ) , 77 ( 7 2 ) , 63 ( 7 9 ) . From  t h e above  mixture,  41c  was c h a r a c t e r i z e d a s 2 a , 2 b , 6 b , 6 c -  tetrahydrobenzo[a]cyclopropa[cd]pentalene-l,2-dicarboxylic MHz, C D C I 3 ) S : 7.5-7.1 (m,  ^H NMR (400 with  41a),  4.29  (d,  IH,  J = 6,6,6 H z , Hgc). 3.67 ( d d ,  J  IH, J  =  6  =  6,6  4H,  Hz,  anhydride.  aromatic  Hgt,) .  Hz,  overlapping  3.99  (ddd,IH,  H 2 b ) , 3.01  (dd, IH,  J = 6,6 H z , H 2 a ) ppm. GC-MS (100), found  126  (DB-1,  ( 2 0 ) . Exact  times  i n ethyl  a  mass  41  was  (M+,  3 6 ) , 198  calculated  acetate  analytically and  function of conversion  were r e c o r d e d 1  224  for  ( 7 ) , 180 ( 3 3 ) , 152  C14H8O3:  224.0473,  224.0470. Compound  as  E I ) m/e:  the photoproduct  of  (A  >  ratios  290  nm)  were  the temperature  5 °C/min t o 230 °C f o r 1 m i n .  program:  three  monitored  and p l o t t e d g r a p h i c a l l y i n t h e t e x t .  o n GC (DB-1) w i t h  min, rate  photolyzed  150  Ratios °C f o r  T h e r e l a t i v e GC r e s p o n s e  o f t h e compounds was c a l i b r a t e d f r o m NMR i n t e g r a t i o n . A n h y d r i d e 4 1 (200 ethyl  acetate  and  photolyzed  This  s o l u t i o n was t h e n  and  evaporated.  diethyl  ether  diazomethane until of  (A  stirred resulting  and  treated  (from  Diazald, remained  diazomethane.  >  with  The  the s o l u t i o n  unreacted  mg, 0.90 mmole)  290 100  yellow at  bright  dissolved  nm) ml  o i l  room  Aldrich);  This  was  t o complete d r y methanol  ml  of  conversion. f o r 10  h  was d i s s o l v e d i n a n h y d r o u s temperature  with  excess  d i a z o m e t h a n e was a d d e d  dropwise  yellow  was s t i r r e d  t h e r e a c t i o n was q u e n c h e d o v e r a c i d i f i e d  i n 500  indicating  an  excess  f o r a n o t h e r 30 m i n b e f o r e  ice, diluted with diethyl  ether.  dried  with  MgSO^,  filtered,  b a n d s . The f i r s t was 20 mg  and evaporated.  ( y i e l d 8%) o f compound 3, f o l l o w e d  of dimethyl naphthalene-2,3-dicarboxylate^^ MP: IR  51-53 °C ( l i t . ^ ^  by  (400  7.62 MS  MHz,  244  mg  ( y i e l d 20%).  52-54 ° C ) .  C D C I 3 ) 5: 8.25  (m, 2H, Hg + H 7 ) , 3.95  ( E I ) m/e:  three 43  ( K B r ) u^ax^ 1733 ( s , C = 0 ) , 1717 ( s , C = 0 ) , 1288 ( s , C-0) NMR  H5  Chromatography gave  (64,  ( s , 2H, H^ + H 4 ) , 7.91 (m, 2H,  ( s , 6H, 2 x m e t h y l )  M+),  213  cm'^.  (100),  183  ppm. ( 3 3 ) , 127  (81),  63 ( 7 5 ) . The  third  band  was 21 mg  ( y i e l d 9%) o f compound 2 9 f ( p r e v i o u s l y  characterized).  Acetone-Sensitized Photolysis Anhydride acetone  and  conversion resulted  in  conversion by  was  photolyzed  the  reaction  was  two  products  (41a  the  (12%)  decomposition was  37  :  63  (A  >  290  nm)  monitored  by  GC  and  41c);  analytically to  show  prolonged  in  complete  photolysis  of  4 1 c . The r a t i o  o f 41a t o 41c a t low  by  GC  response  with  the  calibrated  an  NMR  study,  (A > 290 nm)  compound 41 ( 1 5 mg)  i n 1 ml o f acetone-dg  t o complete c o n v e r s i o n and a n a l y z e d by  NMR  was (GC)  show a 64 ( 7 2 ) : 36 ( 2 8 ) r a t i o o f 4 1 a t o 4 1 c .  Solid  State Photolysis On a n a n a l y t i c a l  for  photolyzed  NMR. In  to  to  41  scale,  c r y s t a l s o f 41 w e r e p h o t o l y z e d  4 h a n d a n a l y z e d b y GC. The c r y s t a l s w e r e  yellow  with  no  s i g n o f m e l t i n g . Two p r o d u c t s  cracked  and  (A > 260 turned  nm)  dark  were formed, 41a and 41c,  in a ratio  o f 2 : 5 a t 7% c o n v e r s i o n .  F o r NMR, photolyzed the  until  crystals  CDCI3  and  c r y s t a l s o f 41 ( a p p r o x . there  (13  was  h).  analyzed  The  by  no  further  dark  NMR  10  mg)  in  change  yellow  an  in  crystals  NMR  tube  were  the appearance o f  were  dissolved  in  (GC) w h i c h s h o w e d a 4 1 : 4 1 a : 4 1 c r a t i o o f  84 ( 9 2 ) : 4 ( 3 ) : 12 ( 5 ) r e s p e c t i v e l y .  Deuterium L a b e l l i n g  Study  Compound 41-D ( 2 0 mg) i n 2 m l o f CDCI3 was p h o t o l y z e d t o c o m p l e t e c o n v e r s i o n t o 41a-D, was  transferred  to  an  NMR  41b-D,  tube  and  and  41c-D.  analyzed.  This  (A > 290 nm) mixture  The s i g n a l s  was  f o r 41a-D  are d e s c r i b e d below. NMR overlapping H2),  (400  with  MHz)  5:  7.5-7.1  (m,  3.50H  4 1 c - D ) , 5.91 (m, l.OOH, H^),  4.57 ( d i s t o r t e d s, 0 . 8 8 H + 0 . 1 2 D ,  Hg^).  +  0.50D,  aromatic  5.48 ( d , l.OOH, J = 6 H z ,  4.42  ( s , 0.63H  +  0.37D,  H2b) ppm. The  signals  ^H  NMR  f o r 41b-D a r e b e l o w .  (400  MHz)  1.33H + 0.67D, H5 + Hg),  8: 8.59 ( s , l . l l H  7.82 (m, 2.00H, Hg + H^)  Below a r e t h e s i g n a l s ^H NMR with J  41a-D),  PPm.  f o r 41c-D.  ( 4 0 0 MHz) 5: 7.5-7.1 (m, 3.5H + 0.5D, a r o m a t i c 4.30  = 6,6,6 H z , Hgc).  (dd,  + 0.89D, H^ + H 4 ) , 8.14 (m,  ( d , 0.56H + 0.44D, J = 6 H z , Hgb), 6.64 ( d d , 0.78H + 0.22D,  l.OOH, J = 6,6 H z , H 2 a ) •  J  =  6,6  overlapping  4.00 ( d d d , l.OOH, Hz,  H2b),  3.00  D. 2 , 3 - D l b e n z o y l - l , 4 - d l h y d r o - l , 4 - e t h e n o n a p h t h a l e n e (42)  Direct  Solution Small  Photolysis  samples  of  compound  acetonitrile  for photolysis  by  shown  one  GC  and  product  secondary In  NMR  compound  f o r 10 m i n u t e s  o f 84 ( 9 2 )  reaction  caused  conversion.  and  This  gave  monitored  of  a  42 was p h o t o l y z e d (A > 3 3 0 nm) w i t h and  analyzed  20  by  NMR  (GC)  to  a  a s o l u t i o n o f 42 ( 3 5 mg, 9.7 x 1 0 ' ^  The  was  resulting  photolyzed  mixture  of  mg  (A 42a  >  330  nm)  a n d 42c was  : hexanes  o f a n i n s e p a r a b l e 75 : 25  mole)  (1:9 v/v)  m i x t u r e o f 42a  1,6c-dibenzoyl-2b,6b(2aH)-dihydrobenzo[a]cyclopropa[cd]pentalene  (42c) , f r o m w h i c h % 42a),  was  the formation  chromatographed t w i c e , e l u t i n g w i t h a d i e t h y l ether solution.  i n benzene and  : 16 ( 8 ) .  a preparative scale,  complete  The  photolysis  i n 4 m l o f b e n z e n e i n a 10 m l p h o t o t u b e to  dissolved  (42c).  study,  CDCI3 i n a n NMR t u b e  On  (A > 330 nm).  Further  photoproduct  42 : 42a r a t i o  were  t o be s o l v e n t - i n d e p e n d e n t w i t h t h e f o r m a t i o n o f o n l y  (42a).  an  42  NMR  the latter  ( 4 0 0 MHz)  i scharacterized  5: 8.0-7.1 (m, 14H, a r o m a t i c o v e r l a p p i n g w i t h  6.08 ( d , I H , J = 3 H z , H 2 ) ,  J = 8 Hz, H2b), GC-MS  below.  4.90  ( s , I H , Hg^),  4.12  (d, IH,  3.78 ( d d , I H , J = 8,3 H z , H 2 a ) Ppm-  (DB-1,  E I ) m/e: 362 (M+, 2 ) ,  257 ( 3 ) , 105 ( 1 0 0 ) , 77 ( 3 1 ) .  E x a c t mass c a l c u l a t e d f o r C26H2^802- 3 6 2 . 1 3 0 7 , f o u n d  362.1295.  B e n z o p h e n o n e - s e n s i t i z e d P h o t o l y s i s o f Compound 42 On five-fold  an a n a l y t i c a l excess  scale,  (w/w)  of  a  small  amount  benzophenone  were  of  compound  dissolved  42  and  a  i n benzene  and  photolyzed  (A >  330  run)  to  complete  conversion.  showed t h e f o r m a t i o n o f 4 2 a ; o n l y t r a c e a m o u n t s On and  a preparative scale,  benzophenone  photolyzed silica (1  (A  (300  >  330  mg,  9  v/v)  gave  p r o p a [cd] p e n t a l e n e IR  (neat)  NMR  of  (400  1682  5:  ( d , I H , J = 2 H z , Hg^) MS  ( E I ) m/e:  362  ml  ether  petroleum  : in  the  first  detected.  7.5 x 1 0 " ^ m o l e )  of  conversion.  benzene  was  Chromatography on ether  (30-60  band.  The  °C)  second  o i l (yield 59%).  ( s , C=0) , 1599  MHz)  8  complete  (42a) as a c o l o r l e s s  Vj^^^^:  in  monitoring  2a,6c-dibenzoyl-2b,6b-dihydrobenzo[a]cyclo-  (m) , 1279  (s)  cm"!.  8.0-7.1 (m, 14H, a r o m a t i c ) ,  = 5,2 H z , H i ) , 5.50 ( d , I H ,  4.40  mmole)  benzophenone  b a n d c o n s i s t e d o f 16 mg  J  to  gel eluting with diethyl  :  o f 4 2 c was  a s o l u t i o n o f 42 ( 2 7 mg, 1.7  nm)  GC  J  =  5  Hz,  H2),  4.63  (100),  77  5.94 ( d d , I H ,  (s,  IH,  H2b),  ppm. (M+,  70),  105  c a l c u l a t e d f o r C26H18O2: 3 6 2 . 1 3 0 7 , f o u n d  (20).Exact  mass  362.1298.  S o l i d S t a t e P h o t o l y s i s o f Compound 42 Crystals (A  >  NMR  indicated  a  1  290  :  of  nm)  1  42  for an  ratio.  : 1 ratio In  placed  in  conversion  In  a  to  two  and  photolyzed  products,  42a  and  42b  to  in  yellow another  o f 42a t o 42b. study,  crystals  were c r u s h e d  b e t w e e n two  pairs  of  330  tube  b y NMR w h i c h showed a 1 4 % c o n v e r s i o n  preparative  >  NMR  l o n g e r p h o t o l y s i s (45 h ) , t h e u n m e l t e d  a  (A  an  15 h t o g i v e u n m e l t e d y e l l o w c r y s t a l s . A n a l y s i s b y  8%  c r y s t a l s were a n a l y z e d 1  were  nm)  f o r 20  h.  o f 42 ( 4 3 mg,  microscope  slides  1.2 x 1 0 " ^ m o l e ) and  photolyzed  The u n m e l t e d y e l l o w c r y s t a l s w e r e  b y NMR w h i c h i n d i c a t e d a 4 2 a : 42b r a t i o  o f 59 : 4 1 a t  38%  analyzed  conversion.  Chromatography  on  silica  gel  using  a 1  ; 9 (v/v) mixture of  e t h e r t o h e x a n e s as t h e e l u e n t gave t h r e e o v e r l a p p i n g bands. band  contained  starting  t h e t h i r d b a n d was conditions  as  m a t e r i a l 42;  rechromatographed  above  to  two  g i v e 4 mg  of  h y d r o b e n z o [a] c y c l o p r o p a [ c d ] p e n t a l e n e (yield  second  The  first  b a n d c o n s i s t e d o f 42a  more  times  under  the  ( n e a t ) v^^y.: NMR  J  = 6 Hz,  J  = 6,6 MS  Hgb).  Hz,  (400  (42b)  (El)  ( s , C=0) , 1597  MHz)  5:  (ddd,  IH,  3.64  H2b),  1651  3.23  m/e:  7.6-6.7 J  =  (m,  as  a  362  (M+,  On  an a n a l y t i c a l  benzene.  One  scale,  product  (m) , 1273 14H,  6,6,6  ( d d , I H , J = 6,6 5),  Photolysis of Benzosemibullvalene  Hz,  105  colorless  o i l  (s)  cm'^.  a r o m a t i c ) , 4.61  Hz,  Hg^).  H2a)  3.49  (d, IH, (dd,  Ppm.  (100),  77  (44).  E x a c t mass  362.1312.  compound 42a was (42c)  was  p h o t o l y z e d (A >  detected  by  : 41 = 42a  GC  330  (DB-1)  analytically  The  structures r e a c t i o n was  at  a  (43)  Photolysis  S o l u t i o n s o f 43  m o n i t o r e d b y GC  nm)  : 42c.  E. M e t h y l 2 - B e n z o y l - l , 4 - d i h y d r o - l , 4 - e t h e n o n a p h t h a l e n e - 3 - c a r b o x y l a t e  Direct Solution  IH,  42a  p h o t o s t a t i o n a r y s t a t e c o m p o s i t i o n o f 59  have  same  1,2-dibenzoyl-2a,2b,6b,6c-tetra-  c a l c u l a t e d f o r C26H18O2: 3 6 2 . 1 3 0 7 , f o u n d  were  and  9%). IR  in  diethyl  i n benzene, a c e t o n i t r i l e ,  photolyzed  (DB-1). 43a  Two and  (A  >  330  nm)  major photoproducts, 43b,  independent  hexanes, to  and  complete  subsequently  methanol  conversion, shown  to  w e r e s e e n a l o n g w i t h some m i n o r p r o d u c t s .  of solvent.  A s o l u t i o n o f k e t o - e s t e r 43 as  above  to complete  r e s u l t i n g mixture at  a ratio A  o f 50  c o n v e r s i o n , and  : 25  : 17  of  ( 4 3 a , 43b,  : trace : 8  compound  : trace,  43  (130  p l a c e d i n f o u r 10 m l p h o t o t u b e s  conversion  as  monitored  by  GC.  The  the r e s u l t i n g y e l l o w o i l chromatographed ether 47 mg two  i n 1 ml  and  hexanes  of a white crystal  (1  solid  : 19 v / v ) (yield  morphologies,  as  CDCI3  was  t h e i n t e g r a t e d NMR  showed s i x p r o d u c t s  solution  b e n z e n e was  (25 mg)  43h,  spectrum  43c,  43d,  0.411  and  photolyzed  benzene  IR C=0),  ( n e e d l e s ) 106-107 °C, (KBr, needles)  silica  prisms,  1224  ( s , C-0)  IR C=0),  1225 %  J  =  Hgb),  gel  NMR  4.57  ( s , IH, H2b),  H^),  ^723  8.0-7.2  5.27  m/e:  77  diethyl  band  contained  hexanes  of methyl  gave  2a-benzoyl-  (43a).  °C.  C=0),  1674  (s,  benzoyl  (s,  e s t e r C=0),  1677  (s, benzoyl  9H,  aromatic),  ( d , I H , J = 5 Hz,  3.45  316  (80).  (m,  ( s , 3H,  (M+,  Exact  methyl)  28), mass  H2),  256  5.93  (dd,  IH,  4.69  (d, IH, J = 3  228  (40),  Hz,  ppm.  (31),  calculated  for  152  C21H16O3:  (30),  316.1100,  316.1103. UV  (CH3CN) X^^^:  Anal. H,  ^max^  ( 4 0 0 M H z ) 5:  (EI)  ester  and  cm"l.  Hz,  (100),  found  prisms)  ( s , C-0)  (s,  complete  using  first  of  cm-1.  3,5  MS 105  (KBr,  ( p r i s m s ) 113-114  ^niax^ ^^33  43e)  evaporated  2b,6b-dihydrobenzo[a]cyclopropa[cd]pentalene-6c-carboxylate MP:  and  to  36%). R e c r y s t a l l i z a t i o n from and  the  mmole) i n 40 m l  was  t h e e l u e n t . The  needles  of  respectively.  mg,  on  photolyzed  244  (e 1 4 0 0 0 ) , 277  C a l c d . f o r C21H16O3: C,  sh  7 9 . 7 3 ; H,  (e 3100) 5.10.  nm. Found:  C,  79.48;  5.15. The  second  band  contained  29  mg  of a white  solid  (yield  22%).  Recrystallizatlon identified  as  from  pentane  methyl  IR 1253  100-101  (300  (s,  MHz) (s,  ( s , 3H, m e t h y l ) ,  ester  C=0) ,  1663  (s,  was  benzoyl  ( E I ) m/e:  5: IH,  3.66 316  7.7-7.2 Hgb),  (m,  4.07  9H, a r o m a t i c ) , 6.29 (d,  IH,  J  ( d d , I H , J = 8,3 H z , H2a)  (M+,  7 ) , 284  ( 8 ) , 180  =  8  C=0) ,  (CH3CN) An,aj^: 244  Anal,  calcd.  Hgt),  ( 5 0 ) , 105  (100),  PPm.  ( 2 3 ) , 152  (e 1 6 5 0 0 ) , 280 s h (e 4 9 0 0 )  f o r C2iH3^503: C, 7 9 . 7 3 ; H,  (d, IH,  Hz,  ( 7 2 ) . E x a c t mass c a l c u l a t e d f o r C21H16O3: 3 1 6 . 1 1 0 0 , f o u n d UV  H,  compound  ( s , C-0) c m ' l .  MS 77  this  (43b).  ^^^^  = 3 Hz, H 2 ) , 4.62  3.72  and  °C.  (KBr)  NMR J  prisms  6c-benzoyl-2b,6b-dihydrobenzo[a]cyclopropa[cd]-  pentalene-l(2aH)-carboxylate MP:  gave  5.10.  316.1106.  nm. Found:  C,  79.80;  5.10.  Benzophenone-sensitized In  a  0.2  ml  a n a l y t i c a l phototube,  i n 43 a n d c a . 0.2  M  glass  nm).  (A  >  330  in  Solid  three  showed  extended  a b e n z e n e s o l u t i o n o f 0.02  was  the  photolyzed  formation  photolysis  through  o f two  gave  M  uranium  photoproducts  similar  results  to  irradiation.  State  Photolysis  Crystals filled  benzophenone GC  (43a and 43h), however, direct  Photolysis  Pyrex new  of  43  were  analytical  products:  photolyzed  phototubes.  43d,  d e t e c t e d a t low c o n v e r s i o n s ,  43e, but  and at  GC 43f.  (A  >  290  showed  the  Neither  conversions  nm)  43a  above  in  nitrogen  formation nor ca.  of  43b  were  20%,  the  crystals  began  to  melt  and  stick  t o the tube s u r f a c e , and  detectable  a m o u n t s o f compound 4 3 a b e g a n t o f o r m . In  an  NMR  photolyzed showed  no  in  an  sign  of  a t 17% c o n v e r s i o n On  a  crystals  NMR  tube  melting.  placed  the  crystals  in  three were  until NMR  the  of  43  yellow  but  showed  signs  silica  gel  diethyl  92:8  were  using  (v/v),  to  6c-benzoyl-  6b-carboxylate  (43f,  >  dissolved a  were  yellow  but  mixture  : 20.  0.921  mmole)  290  nm)  until  of  melting  (18%  benzene  and  in  s o l v e n t system o f hexanes and  give  rechromatographed  methyl  no  : 30  ( 2 9 1 mg,  (A  43  reaction  o f 50  photolyzed  on  was  of  of  turned  and  chromatographed  band  sample  vials  crystals  first  mg)  : 43f r a t i o  crystals  The  ether,  the  10  analysis  scale,  GC).  The  by  (approx.  i n d i c a t e d a 4 3 d : 43e  preparative  were  conversion  study,  three as  above  overlapping  bands.  to  mg  give  13  of  2a,2b-dihydrobenzo[a]cyclopropa[cd]pentalene-  yield  4.5%).  Recrystallization  from  hexanes  gave c o l o r l e s s n e e d l e s . MP: IR 1285  162-163  ( K B r ) Umax-'  ( s , C-0)  3.44  decoupling (J  (300  = 5 H z , H i ) , 5.40  H2b),  =  3  (dd,  MHz)  (s,  ester  C=0) ,  1668  6:  7.7-7.1  (m,  (s,  IH,  J  = 8,3 Hz, H g a ) , 3.12  irradiation of  Hj^  (d,  IH,  C=0) ,  =  (J = 8 5  Hz)  Hz); and  irradiation  collapses  collapses  o f Hgb s i m p l i f i e s Hg^ t o a d o u b l e t  Hg^  of to  (J = 3 Hz).  6.06 J  =  ( d , IH, 8  ( s , 3H, m e t h y l ) ppm. Hg  H z ) ; i r r a d i a t i o n o f Hg c o l l a p s e s H^ t o a s i n g l e t  (J  benzoyl  9H, a r o m a t i c ) ,  ( d d , I H , J = 5,3 H z , H g ) , 4.07  experiments:  Hga t o a d o u b l e t doublet  1^42  cm'^.  NMR J  °C.  Hg^ a  Hz, Spin  to  a  and  simplifies  collapses singlet;  doublet  Hg  to  a  irradiation  MS 105  ( E I ) m/e:  (100),  found  77  316  (M+,  (35). Exact  12), mass  284  ( 1 3 ) , 256  calculated  ( 2 0 ) , 152 ( 2 0 ) ,  f o r C2iH3^603:  316.1100,  316.1098. (CH3CN) X^^^:  UV  Anal,  calcd.  240 (€ 9 5 0 0 ) ,  f o rC2i%603:  280 s h (e 1 7 6 0 ) nm.  C,  79.73;  H,  510.  Found  C,  79.73;  H, 5.16. The crystal  assigned  structure  structure  determination.  ^21^1603' o r t h o r h o m b i c ,  and  the  second third  band  band  inseparable o i l y  also  The  crystal  space group Pbca,  c = 8.637(2)Â, V = 3197(1)Â3, The  was  Z = 8,  was  190  of  data  by  are  an  as  X-ray  follows:  a = 33.023(2)Â, b = 11.210(1)Â,  = 1.314 g / m l , R = 0.042. mg  of  recovered  was r e c h r o m a t o g r a p h e d  mixture  supported  starting  material  a s a b o v e t o g i v e 26 mg o f a n  photoproducts  43d  and  43e  (75  : 25).  Compound 4 3 d was c h a r a c t e r i z e d a s a m i x t u r e w i t h 4 3 e . IR  (neat,  (s, benzoyl  ( 3 0 0 MHz, C D C I 3 ) S : 7.6-6.8 (m,  4 3 e ) , 4.40  Hgc J  =  with  6,6  Hz,  H2a  (d,  IH,  H2b),  J = 6 H z , Hg^),  3.00  c a n be d i s t i n g u i s h e d different  respectively.  Hgb  ' e s t e r C = 0 ) , 1673  9H,  aromatic  and  H2a;  (dd,  from  compositions  a  Lanthanide  those  of  doublet  (J  s h i f t reagent  =  6  o f 43e b y a n a l y z i n g  several  o f Hg^,  studies  irradiation  collapses and  were  H2b also  to  Hg^  of  a  to  H2b  : 1,  modifies  irradiation of a  doublet  performed  spectra  1 : 1 to 4  H2a m o d i f i e s H2b a n d Hg^,;  Hz)  (dd, IH,  I H , J = 6,6 H z , H2a) Ppm. The p e a k s o f  Spin decoupling experiments:  m o d i f i e s Hgj,; i r r a d i a t i o n to  3.40  o f 43d and 43e, v a r y i n g from  irradiation  overlapping  3.62 ( d d d , I H , J = 6,6,6 H z ,  s l i g h t l y o v e r l a p p i n g w i t h 43e) , 3.45 ( s , 3H, m e t h y l ) ,  43d  Hgj.  m i x t u r e w i t h 4 3 e ) u^ax- ^^^^  C = 0 ) , 1267 ( s , C-0) cm'^.  NMR with  1:1  to  singlet  and  (J = 6 Hz). distinguish  Hga  ^2h-  from  to  the  site  of  substituents), Successive (from  reasoned shift  should  be  additions of  Aldrich)  to  reagent  4,  t h e NMR  were  assigned  graphically  Hg^  and  5  30  43d  mole  carbonyl ^2h-  than  %  of  Eu(hfc)3  a n d 4 3 e showed a g r e a t e r  3.40. T h e r e f o r e  Hg^ r e s p e c t i v e l y .  closer  (the  deshielded  and  of  at  these  signals  The r e s u l t s a r e p r e s e n t e d  i nthe text.  GC-MS ( E I , DB-1) m/e: 316 (15),  20,  mixture  a t S 3.00 c o m p a r e d t o t h a t to  strongly  10,  shift  being  complexation  more  0,  ^2a'  that  105  (100),  316.110, f o u n d The  77  (M+,  1 0 ) , 284  ( 6 9 ) . Exact  mass  ( 4 0 ) , 179  calculated  (10),  152  f o r C21H15O3:  316.1097.  spectral  data  f o r 43e  a r e from  mixtures  with  43d and  are d e s c r i b e d below. IR  ( n e a t , 1:1 m i x t u r e NMR  (300  w i t h 4 3 d ) w^ax- d e s c r i b e d a b o v e .  MHz,  CDCI3)  o v e r l a p p i n g w i t h 4 3 d ) , 4.35 ( d , I H , J J  =  6,6,6  Hz,  Hgc  slightly  6: =  6  7.6-6.8 Hz,  overlapping  with  J = 6,6 H z , Hgb), 3.18  (dd, IH, J  =  methyl),  3H,  overlapping  3.17  decoupling irradiation  experiments: of  Hg(,; i r r a d i a t i o n HgbHgb  A  (s,  shift  Hga  methyl  irradiation  modifies  Hg^  6,6  of  Hz,  Hg^  (m,  Hg^),  9H,  3.58  study  was  (ddd, IH,  4 3 d ) , 3.33 Hga  (dd,  overlapping  with  Hga)  modifies  Hga  a n d Hg^,; i r r a d i a t i o n  Spin  and  o f Hg^  IH,  with  ppm.  o f Hg^, c o l l a p s e s Hg^ t o a s i n g l e t a n d m o d i f i e s reagent  aromatic  ^èc'  modifies Hga  and  p e r f o r m e d a s a b o v e t o a s s i g n Hga a n d  (see t e x t ) . GC-MS ( E I , DB-1) m/e: 316 (M+, 5 ) , 284 ( 7 ) , 152  77 ( 3 8 ) . E x a c t mass c a l c u l a t e d f o r C 2 i H i g 0 3 :  ( 8 ) , 105  316.1100, f o u n d  (100),  316.1103.  P h o t o l y s i s o f Compound 43 i n P o l y [ m e t h y l m e t h a c r y l a t e ] Compound  43  ( 3 mg, 1 x 1 0 ' ^  m o l e ) was d i s s o l v e d a l o n g w i t h 30 mg  o f medium  molecular  in  2  o f methylene c h l o r i d e and spread  The  s o l v e n t was e v a p o r a t e d  ml  clear  films  (A > 290  prior  were  nm).  dissolved  weight  u n d e r vacuum  photolyzed  i n CH2CI2  t o GC  poly(methyl  For monitoring  was to  ( 4 3 a , 4 3 b , 4 3 h , 4 3 d , a n d 43e)  12  respectively.  similar  and  a  preparative  scale,  a  2.0 g o f medium m o l e c u l a r w e i g h t  CH2CI2  was  evenly over with for  poured the inner  nitrogen 50  into  a  h r . The  tube  min was  Aldrich)  and  through  the  a  slides. resulting  Pyrex  portions  of  film  to precipitate  complete  conversion  i n a GC r a t i o  filter were  t h e PMMA  gave  five  o f 34 : 12 : 30 :  photolysis  (-50  °C)  gave  slower. s o l u t i o n o f 43 ( 2 0 0 mg, 0.63 mmole)  PMMA ( f r o m  Aldrich)  i n 30  ml o f  24 x 5 cm P y r e x v a c u u m - s a f e t u b e a n d s p r e a d  surface.  f o r 30  h,  added  low temperature  r e s u l t s , b u t t h e r a t e was much On  °C  (from  three microscope  the reaction,  Irradiation  A  over  20  products : 12,  methacrylate)  f o r 24  at  and methanol  analysis.  (PMMA) F i l m  The  solvent  followed sealed  by  under  was  removed  pumping  on  nitrogen  a  by  flushing  vacuum  and  line  photolyzed  (A > 2 9 0 nm) a t 20 °C. The t u b e was r o t a t e d e v e r y  15 m i n a n d t h e r e a c t i o n  monitored  9 3 % . The  dissolved  by  GC  to  i n 100  a  ml  s o l v e n t was e v a p o r a t e d point  most  stirred  f o r another  and  the  of  as  the eluent  of  30  min  was  and  to  had  g e l using  three  major  and  75  ml  polymer  remained,  precipitated.  precipitate  filtered  of  was  75 m l o f m e t h a n o l was a d d e d . The  approximately  polymer  silica gave  conversion  CH2CI2  until  the  solution  Chromatography on  maximum  The  the rest  evaporated  to  hexanes-diethyl bands.  The  of  first  a  at  mixture the  which was  polymer  yellow o i l .  ether,  9:1 v / v ,  band  consisted  of  61 mg o f 4 3 a ( y i e l d 3 1 % ) . The s e c o n d b a n d c o n t a i n e d 27 mg o f  solid  (yield  14%). Recrystallization  were c h a r a c t e r i z e d as m e t h y l  from  hexanes  a  white  gave p r i s m s  which  6c-benzoyl-2b,6b-dihydrobenzo[a]cyclopropa-  [cd]pentalene-2a-carboxylate  (43h).  MP: 1 2 9 - 1 3 0 °C. IR 1287  (KBr)  ^718  (s, ester  C=0),  1676  ( s , b e n z o y l C=0),  ( s , C-0) cm-1. NMR  J  Vjnax-  =  5,2  ( 3 0 0 MHz) 5: 7.9-7.1  Hz,  H]_), 5.64  (d,  (m,  IH,  9H,  J  =  aromatic),  (100), found  ( E I ) m/e: 77  316 (M+, 2 5 ) , 284  (30).  Exact  mass  (dd, IH,  6 H z , Hg) , 4.55 ( s , I H , Hgb) ,  4.30 ( d , I H , J = 2 H z , Hgt,) . 3.70 ( s , 3H, m e t h y l ) MS  5.91  ppm.  ( 4 9 ) , 256  calculated  ( 2 5 ) , 152  f o r C21H16O3:  ( 1 5 ) , 105 316.1100,  316.1105. 278 s h (e  UV (CH3CN) A ^ a ^ : 245 (e 2 5 8 0 0 ) , Anal, calcd.  f o r C21H16O3: C, 7 9 . 7 3 ; H,  3 9 0 0 ) nm. 5.10.  Found:  C,  79.82;  H, 5.14. The 43e  third  band  contained  a  3  : 1 m i x t u r e o f compounds 4 3 d t o  a s i n d i c a t e d b y GC.  P h o t o s t a t i o n a r y S t a t e o f B e n z o s e m i b u l l v a l e n e s 43a and 43c C r y s t a l s o f 43a acetone  to  photolyzed the as the  make (A  >  formation  up 290  were  dissolved  approximately nm).  of  The  one  43c.  The  reaction  was  rate  of  reaction  in  c a s e s , t h e 43a : 43c r a t i o  i n benzene,  0.01  independent acetone  after  M solutions,  reactions compound,  acetonitrile,  monitored  and a n a l y t i c a l l y by  subsequently of  and  solvent,  GC  to  show  characterized except  that  was n o t i c e a b l y s l o w e r . I n a l l t h r e e  prolonged  irradiation  (corrected  for  detector  response  o f compound 43c On  by  NMR)  l e d to the  same  43a  i n 40 m l  (A >  ratio  The  of  83  :  17.  c h r o m a t o g r a p h e d on  silica  as  Two  solvent.  f o l l o w e d by  as  the  43c.  pure  c o m b i n e d and  resulting from  hexanes  290  of  50  photolyzed  nm)  solvent  to  a  was  separation  isolated  mg  (0.16  i n f o u r 10 m l  time-invariant  concentrated  (32 mg)  of  43c  was  and  of  a  gave  IR 1329  100-101 (KBr)  white  solid  colorless  J = 3 Hz, (s,  3H,  105  H2),  MHz)  from  again.  43a and  The  (yield  needles  ester  (s)  5:  43c  ( 1 : 9  was  v/v) first,  achieved,  chromatographed  fractions  24%).  of  (El)  m/e:  316  77  (45).  of  43c  separation  Recrystallization  methyl  1-benzoyl-2b,6b(43c).  (M+,  1639  (s,  benzoyl  C=0) ,  cm'l. (m,  3.97  I H , J = 8,3  Exact  C=0) ,  7.6-7.1  ( s , IH, Hgb), (dd,  (d, IH, Hz,  20),  mass  9H,  284  aromatic),  J  H2a)  =  (d,  Hz,  H2b)>  (10),  152  IH, 3.74  PPm.  (4),  calculated  8  5.95  for  256  C21H16O3:  (13),  316.1100,  316.1100. Anal.  H,  4.96  (s,  1213  3.54  (100),  found  (300  methyl), MS  1726  ( s , C-0),  NMR  :  °C.  Vjj^siK-  ( s ) , 1267  phototubes 43a  hexanes  rephotolyzed  s e p a r a t i o n o f 43c  of  t o a y e l l o w o i l and  dihydrobenzo[a]cyclopropa[cd]penatalene-6c(2aH)-carboxylate MP:  mmole)  r e c h r o m a t o g r a p h e d as a b o v e t o g i v e c o m p l e t e  i n 12 mg  photolysis  o v e r l a p p i n g b a n d s w e r e e l u t e d , compound 43a  above t o g i v e p a r t i a l  were  solution  gel using d i e t h y l ether  A partial 43a  Independent a n a l y t i c a l  ratio.  o f b e n z e n e was  through a Pyrex f i l t e r  and  8:2.  a preparative scale, a  compound  the  was  5.21.  calcd.  for  C2iH]^603:  C,  7 9 . 7 3 ; H,  5.10.  F o u n d : C,  79.63;  P h o t o s t a t i o n a r y S t a t e o f B e n z o s e m i b u l l v a l e n e s 43f C r y s t a l s o f 43f acetone  to  make  were  up  approximately  photolyzed  (A > 290  nm).  formation  of  volatile  one  s t r u c t u r e 43g,  analytical  ratio,  prolonged  of  the  GC  sample.  The  Photoproduct  at  mg  The  : 43g  photolysis photolysis  results  Pure  40%)  was  o f 57  1264  were  of  % J  = 5,2  Hgb),  Hi  =  NMR  (300  Hi),  5.42  4.24  (d,  IH,  Hz)  analytically  indicated  shown  to  : 43g  caused  irreversible  have  the  :  8.  = 2  i n benzene a l s o  the  l e d to  this  decomposition except  by  photolysis  in  order  to  eluting  give  3  solution  of  halted  ether  followed closely  mg  of  photodecomposition.  with diethyl  chromatographed  to  a  p h o t o l y s i s was  avoid  eluted f i r s t  and  of  as  above.  a  and  by  43g.  The  two  colorless  o i l  6c-benzoyl-2a,6b-dihydrobenzo[a]cyclopropa[cd](43g).  1^28  (s,  ester  C=0),  1675  (s,  benzoyl  C=0),  cm'l.  Hz,  3  43g  i n 1 ml o f CDCI3. The  : 43  methyl  MHz)  and  to a doublet  6:  7.9-7.1  ( d d , I H , J = 5,3  decoupling experiments: (J  subsequently  of  isolated  combined  ( n e a t ) ^max^  ( s , C-0)  reaction  and  n o t i c e a b l y slower i n acetone.  rephotolyzed  pentalene-2b-carboxylate IR  s o l u t i o n s and  the  c h r o m a t o g r a p h e d on s i l i c a  was  portions  (yield  acetonitrile,  w e r e t h e same i n a l l t h r e e s o l v e n t s ,  (1 : 9 v / v ) . Compound 43f 43f  pure  43g  ratio  m i x t u r e was  hexanes  M  of  product,  ( 0 . 0 2 5 mmole) o f 43f  a 43f  benzene,  0.01  monitoring  t h a t t h e r a t e o f r e a c t i o n was  7.5  in  43g  a t a p h o t o s t a t i o n a r y s t a t e r a t i o o f 43f  Independent but  dissolved  and  J  =  3  Hz,  ( J = 2 Hz)  Hz,  9H,  a r o m a t i c ) , 5.87  Hg),  4.27  3.73  ( s , 3H,  Hga),  i r r a d i a t i o n of  c o l l a p s e s Hg^,  (m,  Hj^  collapses  to a s i n g l e t ;  a n d c o l l a p s e s Hg^  (d, IH, J  to  i r r a d i a t i o n o f Hg to a  singlet.  IH,  2  Hz,  =  methyl) Hg  (dd,  ppm. a  Spin  doublet collapses  MS (39).  ( E I ) m/e:  316 (M+, 1 3 ) ,  300  ( 8 ) , 152  ( 1 2 ) , 105  E x a c t mass c a l c u l a t e d f o r C2iH2^603: 3 1 6 . 1 1 0 0 , f o u n d  (100),  77  316.1096.  P h o t o s t a t i o n a r y S t a t e o f B e n z o s e m i b u l l v a l e n e s 4 3 h a n d 43b Crystals to  make  of  up  43h  were  approximately  photolyzed  (A  >  290  s t a t e c o m p o s i t i o n o f 43h : independent  photolysis  dissolved  in  0.01  solutions  nm). 43b  of  M GC  = 2  8.  43b  a  This under  and  acetonitrile  and  indicated :  compound  benzene  was  analytically  photostationary verified  identical  by  an  conditions.  Compound 4 3 h r e a r r a n g e s t h e r m a l l y t o 43b i n t h e GC a b o v e 200 °C.  P h o t o l y s i s o f B e n z o s e m i b u l l v a l e n e s 4 3 d a n d 43e A 1 : 1 benzene, 0.02  acetone,  M  the  and  to  the  in  results  43-D  the  H2),  to  make  photolyzed  peak  43e  with  a  materials.  (A  was  dissolved  up  approximately  >  290  maximum  in  nm).  GC  conversion of  Insufficient  conversion  43 ( 4 3 - D ) i n CDCI3  (10  mg) d i s s o l v e d  conversion.  reaction  i n 1 m l o f CDCI3 was p h o t o l y z e d  Compounds  m i x t u r e b y NMR  43a-D  and  f o r the s i t e s  43b-D  were  of deuteration.  f o r 43a-D a r e d e s c r i b e d .  I H NMR 5.90  new  starting  (A > 330 nm) t o c o m p l e t e  5:  a  and  i t s i s o l a t i o n or i d e n t i f i c a t i o n .  Compound  The  43d  acetonitrile  of  Photolysis of Deuterated  analyzed  compounds  analytically  formation  relative  prevented  of  and  solutions  showed 4%  mixture  (dd,  4.69 ( d ,  (300  MHz,  l.OOH, 0.59H  J -1-  only =  non-overlapping  5,3  0.31D,  Hz, J  =  H^), 3  Hz,  signals  5.27 Hg^) .  (d,  are  reported)  0.89H, J = 5 H z ,  3.57  (s,  0.63H  +  0.37D, Hgb),  5:  3.43 ( s , 3.21H, m e t h y l ) ppm.  The  data  f o r 43b-D a r e r e p o r t e d  •'-H  NMR  (300  6.29 ( d , l.OOH, J  MHz,  only  =  Hz,  3  below.  non-overlapping Hg),  4.62  4.07 ( d , 0.78H + 0.22D, J = 8 H z , Hgb),  P h o t o l y s i s o f Deuterated Crystals two  pairs  of  resulting b y NMR.  of  (54  microscope  yellow  solid  Spectral  ( s , 0.72H  mg,  0.17  slides was  expansion  and  mmole)  in  1  reported) J  =  NMR  (300  MHz,  integration  CDCI3,  only  6: 6.06 ( d , 0.68H + 0.32D, J = 5  5,3  Hz,  Hg),  4.07  (d,  0.76H  0.28D,  Hgb),  were (A  crushed >  290  between nm).  The  m l o f CDCI3 a n d a n a l y z e d of  was d o n e . S i g n a l s o f compound 4 3 f - D a r e r e p o r t e d •'-H  +  State  photolyzed  dissolved and  are reported)  3.71 ( s , 3.22H, m e t h y l ) ppm.  43 ( 4 3 - D ) i n t h e S o l i d  43-D  signals  the  reaction  mixture  below.  non-overlapping  signals  Hz,  (dd,  H]_) ,  5.40  + 0.24D, J = 8 H z , Hgb),  are  l.OOH,  3.13 ( s ,  2.88H, m e t h y l ) ppm. The mixture  mixture  of  was c h r o m a t o g r a p h e d o n s i l i c a  hexanes  to  diethyl  and  the  43d-D a n d 43e-D. The analyzed  b y NMR.  •'-H  NMR  third third  was  was 4 3 f - D ,  10  band  Spectral data  a  e t h e r as t h e e l u t i n g  t h r e e o v e r l a p p i n g bands; t h e f i r s t material,  using  the  9  1  (v/v)  solvent. This  second  was  mg o f a 57 : 43 m i x t u r e  was  :  rechromatographed  gave  starting  o f compounds  as  above  and  f o r 43d-D a r e d e s c r i b e d .  ( 3 0 0 MHz, C D C I 3 , o n l y n o n - o v e r l a p p i n g  6: 4.40 ( d , 0.67H + 0.33D, J = 6 3.40  (dd,  Hga),  3.45 ( s , 3.12H, m e t h y l ) ppm.  Hz,  Hgb),  0.80H + 0.20D, J = 6,6 H z , Hgb),  R e s u l t s f o r 43e-D a r e b e l o w .  3.45  bands a r e r e p o r t e d ) ( s , 3.07H,  methyl),  3.00 ( d d , l.OOH, J = 6,6 H z ,  NMR are  reported)  ( 3 0 0 MHz, C D C I 3 , 5:  4.35  (d,  only 0.57H  bands +  non-overlapping  with  0.43D, J = 6 H z , H g ^ ) . 3.33 ( d d ,  0.71H + 0.29D, J = 6,6 H z , H 2 b ) , 3.22-3.16 (m, 4.00H, H2a + m e t h y l ) The analyze  was  evaporated  and  redissolved  in  ppm.  benzene-dg  to  t h e s i g n a l s o f H2a a n d H2b o f compound 43e-D a g a i n . ^H  reported) J  solvent  43d-D  NMR  (400  MHz,  benzene-dg,  only  s i g n a l s o f H2a a n d H2b a r e  S : 2.86 ( d d , 0.71H + 0.29D, J = 6,6 H z , H 2 b ) , 2.80 ( d d ,  = 6,6 H z , H2a) ppm.  l.OOH,  F.  Ethyl 2-Benzoyl-l,4-dihydro-l,4-ethenonaphthalene-3-carboxylate  (44)  Direct Photolysis In  an  benzene and were and  analytical acetonitrile  monitored three  of  CDCI3  to  give five  46  : 35  : 11  larger  complete  44b,  44c,  44d,  44e,  the  of  ethyl  scale,  44c,  44f  band.  The  major  of  reactions  photoproducts  solvent.  However,  integration at high conversion. (approx.  10  mg)  in  330  nm)  to  complete  44d,  44e,  and  44f  in  (28 mg,  8.5  x 10"^  1.5  ml  conversion a  ratio  of  mole)  was  respectively. compound  44  o f CDCI3 a n d p h o t o l y z e d  and  nm).  in  (A > 330  ratio on  o f 45  : 32  silica of  Recrystallization  in a  expansion :  gel a  nm)  from  showed a  10  10:  with  diethyl  white  phototube  solid hexanes  3:  44a,  trace,  ether  (yield gave  and 29%)  prisms  (44a).  MP:  73-74  IR  (KBr)  ( s , C-0)  5,2  : trace,  >  dissolved  2a-benzoyl-2b,6b-dihydrobenzo[a]cyclopropa[cd]pentalene-6c-  ^H NMR =  44b,  GC 44  a s e l u e n t g a v e 8 mg  first  carboxylate  J  (A  Chromatography  (1:9 v/v)  in  1239  ml  44a,  were  290  c o n v e r s i o n . I n t e g r a t i o n o f t h e NMR  respectively. hexanes  : 4  i n 1.5  compound  photolyzed  products  a  dissolved to  were  : 4  On  study,  44  independent  prevented proper  NMR  of  c o n v e r s i o n t o g i v e two  photoproducts  peaks  an  crystals  f o r p h o t o l y s i s (A >  to complete  minor  overlapping In  study,  °C. Un,ax:  1724  (s,  ester  C=0) ,  1677  (s, benzoyl  C=0) ,  cm-1. ( 3 0 0 M H z ) 8:  Hz,  H^),  5.27  8.05-7.15 (m,  9H,  ( d , I H , J = 5 Hz,  aromatic), H5),  4.68  5.91  (dd,  (d, IH, J = 2  IH, Hz,  Hgb)-  4.57  ( s , I H , Hga),  3H, J = 7 H z , m e t h y l ) MS Exact  ( E I ) m/e:  3.88  ( q , 2H, J = 7 H z ,  methylene),  0.96  (t,  ppm.  330 (M+, 5 2 ) , 284 ( 8 ) , 257 ( 9 ) , 105 ( 1 0 0 ) ,  mass c a l c u l a t e d f o r C22H18O3: 3 3 0 . 1 2 5 5 , f o u n d  77 ( 4 0 ) .  330.1255.  A n a l , c a l c d . f o r C22H18O3: G, 7 9 . 9 8 ; H, 5.49.  Found:  C,  80.05;  H, 5.46. The  second  band  contained  2.5  mg  o f e t h y l 6c-benzoyl-2b,6b-  dihydrobenzo[a]cyclopropa[cd]pentalene-l(2aH)-carboxylate  (44b)  as  a c o l o r l e s s o i l ( y i e l d 9%). IR 1248  (neat)  =  3  ( 3 0 0 MHz) 8: 7.6-7.1  H z , Hg),  = 7 Hz, m e t h y l ) MS  (20),  later  152  ( 5 0 ) , 105 330.1255,  for this The  (m,  C=0) ,  aromatic),  ^H NMR  ( d d , I H , J = 8,3 H z , H 2 a ) ,  330  (M+,  with  1.30  IH, 4.06  ( t , 3H,  (100),  1 5 ) , 284 ( 4 0 ) , 257 ( 1 0 ) , 225 ( 4 0 ) , 77  ( 6 0 ) . Exact  mass  180  calculated for  f o u n d 3 3 0 . 1 2 6 0 . M o r e compound 44b was  44e, for  from ethyl  which  synthesized  the  mixture  of  two w e r e c h a r a c t e r i z e d .  (44d) a r e as f o l l o w s :  (m, 9H, a r o m a t i c  ( d , I H , J = 6 H z , Hgb), 44e),  latter  1 : 7 : 2  l-benzoyl-2a,2b,6b,6c-tetrahydrobenzo[a]-  ( 3 0 0 MHz) 5: 7.6-7.0  4 4 e ) , 4.40  (d,  c h a r a c t e r i z a t i o n f r o m t h e p h o t o l y s i s o f compound 4 4 c .  and  data  6.29  4.25-4.10 (m, 2H, m e t h y l e n e ) ,  cyclopropa[cd]pentalene-2-carboxylate  lapping  9H,  t h i r d b a n d was a 5 mg o f a n i n s e p a r a b l e  44d,  Spectral  and  C=0) , 1666 ( s , b e n z o y l  ppm.  ( E I ) m/e:  *-'22^18*-'3•  44c,  ester  4.61 ( s , I H , Hgb),  I H , J = 8 H z , Hgb), 3.66  (d, J  (s,  ( s , C-0) c m ' l . ^H NMR  J  ^^09  Uniax^  3.90  (m,  o v e r l a p p i n g w i t h 44c 2H,  3.60 ( d d d , I H , J = 6,6,6 H z , Hg^  methylene overlapping  overwith  44e),  3.41 ( d d , I H , J - 6,6 H z , H 2 b ) . 3.00 ( d d , I H , J = 6,6  0.85  ( t , 3H, J = 7 H z , m e t h y l )  ppm. P e a k s o f 4 4 d w e r e  Hz, H 2 a ) ,  distinguishable  f r o m t h o s e o f 44e b y s t u d y i n g o t h e r m i x t u r e s w i t h d i f f e r e n t GC-MS ( E l , DB-1) m/e: 330 (M+, 1 ) , 213 ( 8 ) , 180 105  (100),  found  77  ( 2 0 ) . Exact  mass  ratios.  ( 4 ) , 152 ( 2 0 ) ,  c a l c u l a t e d f o r C22H18O3:  330.1256,  330.1253. Data  f o r ethyl  2-benzoyl-2a,2b,6b,6c-tetrahydrobenzo[a]cyclo-  propa[cd]pentalene-l-carboxylate  (44e) a r e below.  ^H NMR ( 3 0 0 MHz) 6: 7.6-7.0 (m, 9H, a r o m a t i c o v e r l a p p i n g w i t h 4 4 c and  4 4 d ) , 4.45 ( d , I H , J = 6 H z , H g ^ ) . 3.90  lapping 44d), 0.66  with  2H,  methylene  over-  3.60 ( d d d , I H , J = 6,6,6 H z , Hg^, o v e r l a p p i n g w i t h  3.33 ( d d , I H , J = 6,6 H z , H 2 b ) , 3.20 ( d d , I H , J = 6,6  Hz, H 2 a ) ,  ( t , 3H, J = 7 H z , m e t h y l ) ppm. GC-MS  105  44d) ,  (m,  ( E I , DB-1)  ( 1 0 0 ) , 77 ( 2 2 ) .  found  m/e: 330 (M+, 2 ) ,  Exact  mass  calculated  213 ( 8 ) , 180 ( 4 ) , 152 ( 1 7 ) , f o r C22H18O3:  330.1256,  330.1259.  Benzophenone-Sens i t i z e d P h o t o l y s i s In  an  were d i s s o l v e d indicated  analytical  i n b e n z e n e a n d p h o t o l y z e d (A > 3 3 0  complete  conversion  GC (DB-1) p e a k . H o w e v e r , converts  s t u d y , c r y s t a l s o f 44 a n d e x c e s s  completely  a s e s t a b l i s h e d b y GC  g  GC  monitoring  t o 44a and 44c i n a s i n g l e i n s e p a r a b l e  a t column temperatures  t o 4 4 b . The r a t i o  > 2 0 0 °C, compound  44c  o f 4 4 a t o 4 4 c ( 4 4 b ) was 48 : 52  (DB-17).  On a p r e p a r a t i v e s c a l e , b e n z o b a r r e l e n e 7  nm).  benzophenone  ( 3 8 mmoles) o f b e n z o p h e n o n e  44 ( 1 6 3 mg, 0.49 mmole) a n d  i n 140 m l o f b e n z e n e w e r e  photolyzed  (A > 330  nm)  solution ether The  i n an  was  (9  chromatographed  : 1 v/v)  second  immersion w e l l  as  band  the  t o c o m p l e t e c o n v e r s i o n . The  on  silica  eluent.  was  58  t h i r d b a n d c o n t a i n e d 57 mg  mg  The  first  ethyl  ( n e a t ) v^^^^:  ( s , C-0) %  J  Hz,  (d,  1.12  MS  IH,  1717  (s,  5.64 J  ester  2  77  330  Hz,  =  Hg^).  methyl) (M+,  (60).  6  tail  28),  Exact  284  mass  a  colorless  o i l  1675  (s,  benzoyl  C=0) ,  9H,  a r o m a t i c ) , 5.90  Hg) ,  4.12  ( q , 2H,  (65)  256  4.51  (s,  J = 7 Hz,  (dd,  IH,  IH,  Hgt,) ,  methylene),  ( 3 0 ) , 226  ( 2 5 ) , 152  c a l c u l a t e d f o r C22H18O3:  (49),  330.1255,  290  of  nm)  in  44 an  (9  mg,  NMR  The  o f the f o u r primary  ratio 54  experiment  :  8 was  crystals  tube  yellow  : 23  : 15  repeated  were  and  44e  ( c a . 8 mg)  were  detected  band.  S t a t e P h o t o l y s i s o f Compound  slightly  was  the  ppm.  o f t h e compound 44c  Crystals (A >  36%) , a n d  330.1262.  the  Solid  (yield  as  C=0) ,  Hz,  A s m a l l amount o f compounds 44d in  (44c)  7.9-7.1 (m,  (d, IH, J  =  ( E I ) m/e:  S:  MHz)  J = 7 Hz,  (100),  found  (400  H^),  ( t , 3H,  105  benzophenone.  cm-1.  NMR  = 6,2  4.29  44a  was  35%). IR  1278  band  diethyl  6c-benzoyl-2b,6b-dihydrobenzo[a]-  cyclopropa[cd]pentalene-2a-carboxylate (yield  g e l w i t h hexanes and  of photoproduct  of  resulting  44 2.7 for  x  lO'^ two  dissolved  photoproducts  mole)  hours  were the  unmelted,  i n CDCI3 f o r NMR  analysis.  44a,  and  photolyzed  44c,  44d,  r e s p e c t i v e l y a t a c o n v e r s i o n o f 47%. i n a 5 h p h o t o l y s i s and  the 44a,  44c,  and The 44d,  44e above and  44e  r a t i o was  64  : 9  : 18  : 9,  r e s p e c t i v e l y a t a 46%  Photolysis of Benzosemibullvalene On  an  analytical  (A > 330  acetone  nm)  (A  volatile of ca.  >  290  product  (A > 290 92  small  nm),  for  samples  of  compound  acetonitrile  (A  >  photolysis.  independent  of  GC  solvent  330  monitoring  at  a  nm)  (92)  44a  and  (5 mg,  0.015  mmole) i n 1 m l  t h e e q u i l i b r i u m r a t i o was  : 8 ( 8 ) f o r 44a  and  c h a r a c t e r i z e d as a m i x t u r e NMR  (400 MHz)  I H , J = 3 Hz,  methylene), H2a),  1.30  44f.  (EI, 77  w i t h 44a  The  and one  conversion  o f CDCI3 was  photolyzed  analyzed  by  ethyl  NMR  J = 7 Hz, DB-1)  (25).  9H,  ( s , IH, Hgb),  IH,  J  = 8 Hz,  methyl)  m/e:  330  Exact  mass  (GC)  to  1-benzoyl-2b,6b(44f)  was  as d e s c r i b e d b e l o w . o v e r l a p p i n g w i t h 44a),  4.20  H2b),  (q,  2H,  3.52  J  =  7  ( d d , I H , J = 8,3  5.94 Hz, Hz,  ppm. (M+,  11),  256  (5),  152  c a l c u l a t e d f o r C22H18O3:  (12),  330.1255,  330.1266.  Photostationary State of Benzosemibullvalenes On  an a n a l y t i c a l  photolyzed  (A  r e a c t i o n was as  nm),  maximum  product,  S : 8.0-7.0 (m, 4.96  (d,  ( t , 3H,  (100),  found  H2),  3.97  GC-MS 105  were  indicated  dihydrobenzo[a]cyclopropa[cd]pentalene- 6c(2aH)-carboxylate  (d,  44  10%. Compound  be  44a  scale,  d i s s o l v e d i n benzene  conversion.  the  only  >  290  monitored product,  scale, nm) b y GC  s m a l l samples of  44b  and  44c  photoproduct  i n benzene, a c e t o n i t r i l e , t o show t h e  formation  i n d e p e n d e n t o f s o l v e n t . The  of  and  44c  acetone.  compound  maximum  were The 44b,  conversion  was c a . 8 5 % . Compound 44c (A  >  290  nm)  (5  mg)  was  to equilibrium  dissolved  in  a n d a n a l y z e d b y NMR  83 ( 8 2 ) : 17 ( 1 8 ) c o m p o s i t i o n o f compounds analytical photolysis  G.  Isopropyl  o f 44b  CDCI3  44b  g a v e t h e same  and  photolyzed  (GC). T h i s  and  44c.  indicated  Independent  ratio.  2-Benzoyl-l,4-dihydro-l,4-ethenonaphthalene-3-carboxylate  (45)  D i r e c t S o l u t i o n P h o t o l y s i s of Compound 45 Crystals benzene,  o f 45 w e r e p h o t o l y z e d  acetonitrile,  and  methanol  m o n i t o r i n g s h o w e d two m a j o r p r o d u c t s reaction  was  typically  50  independent : 30 : 7 : 10  respectively  (use  of  On a l a r g e r dissolved  scale, in  1.5  c o m p l e t e c o n v e r s i o n . NMR ratio  complete  The  45b,  GC  45c,  resulted  The  first  330  nm)  in  conversion.  GC  45d  +  and  the  ratios 45e,  were  and  i n other overlaps).  45f These  later. c r y s t a l s o f 45f ml  of  analysis  CDCI3  (20  mg,  5.8  and p h o t o l y z e d  showed a 45a  : 45b  g e l e l u t i n g w i t h a 1 : 9 (v/v) mixture  hexanes.  >  (DB-1)  band  consisted  of  5  of mg  x  lO'^  : 45d  :  to 45e  chromatographed  diethyl of  mole)  (A > 330 nm)  : 45c  o f 50 : 30 : 8 : 8 : 4. The r e a c t i o n m i x t u r e was  on s i l i c a  (yield  solvent.  DB-17  to  (A  and t h r e e minor p r o d u c t s ,  : 3 o f 45a,  the  a s s i g n m e n t s were v e r i f i e d  were  of  analytically  a  26 % ) . R e c r y s t a l l i z a t i o n f r o m h e x a n e s g a v e c o l o r l e s s  ether  white prisms  to  solid of  isopropyl  2 a - b e n z o y l - 2 b , 6 b - d i h y d r o b e n z o [ a ] c y c l o p r o p a [ c d ] p e n t a l e n e - 6c -  carboxylate  (45a).  MP: % J J  =  NMR  5,2  °C.  (300MHz)  Hz,  Hj^),  5: 8.1-7.2 (ra, 5.26  (d,  = 6 Hz, i s o p r o p y l m e t h i n e ) ,  (s, J  78-79  IH,  H2b).  1-04  = 6 Hz, m e t h y l ) MS  Exact  4.69 3H,  J  344  =  IH, 6  J  =  Hz,  2  (dd,  IH,  ( s e p t e t , IH,  Hz,  methyl),  (M+,  3 6 ) , 302  ( 6 ) , 258  ( 2 1 ) , 105  mass c a l c u l a t e d f o r C23H20O3: 3 4 4 . 1 4 1 2 , f o u n d calcd.  for  Hg^),  4.56  0.65  ( d , 3H,  (100),  77 ( 2 0 ) .  C23H20O3:  C, 8 0 . 2 1 ; H,  344.1408.  5.85.  F o u n d : C,  79.89  5.75. The s e c o n d b a n d  (6.5  mg)  was  overlapping  an  with  inseparable trace  r e c h r o m a t o g r a p h e d a s a b o v e t o remove and  45c.  From  this mixture,  mixture  amounts  of  a 45b IR  C=0),  : 45c = 7 : 3 (neat,  1249  I R NMR 45c),  6.28  5: 7.7-7.1 (m,  (d,  J  IH,  4.60  3.66  =  I . 23  J  =  45d and 45e. T h i s mg  (45b)  was  of  was 45b  characterized  ( s , e s t e r C=0) , 1666  3  Hz,  9H,  aromatic  H2),  5.04  ( s , I H , Hg^,) > 4.04  8,3  Hz,  ( d , 3H, J = 6 H z , m e t h y l ) GC-MS ( D B - 1 , D C I ) m/e:  Exact  45c  (s, benzoyl  cm-1.  ( 3 0 0 MHz)  IH,  and  mixture.  i s o p r o p y l methine), (dd,  45b  i s o p r o p y l 6c-benzoyl-2b,6b-dihydrobenzo-  3 0 % o f 4 5 c ) Uj^^x" 1705  ( s , C-0)  of  45d and 45e, g i v i n g 2  [a]cyclopropa[cd]pentalene-l(2aH)-carboxylate as  5.91  = 5 Hz, H2) , 4.75  (d, J  aromatic),  ppm.  ( E I ) m/e:  Anal. H,  (d,  IH,  9H.  H2a),  overlapping  ( s e p t e t , I H , J = 6 Hz,  (d, IH, J  1-28  with  =  8  Hz,  ( d , 3H, J = 6 H z ,  H2b) ,  methyl),  ppm.  345  (M++1,  22),  mass c a l c u l a t e d f o r C23H20O3: 3 4 4 . 1 4 1 2 ,  285 found  (100), 344.1408.  105  (95).  Benzophenone-Sensitized Crystals  of  P h o t o l y s i s o f Compound 45  45  (2 mg)  and an a p p r o x i m a t e l y  1 0 - f o l d molar  o f benzophenone were d i s s o l v e d i n benzene and p h o t o l y z e d to  complete  conversion.  45a a n d 45c as t h e  GC  showed  (A  >  1.0  g  330  nm)  (5.5 in  Chromatography of diethyl  formation  (57  mg,  mmoles) 40  on  The  The t h i r d b a n d  of  ml  of  of  silica  1.5  benzophenone  benzene gel  to  using  a  x  1  :  9  s e c o n d c o n t a i n e d 25 mg  consisted  of  20  mg  IR 1283  (neat)  ^^18  Umax^  ( s , C-0)  cm-1.  NMR  (300  =  IH, (d,  6 J  =  conversion. (v/v)  The  mixture  first  was  o f compound 4 5 a ( y i e l d 4 7 % ) .  of  isopropyl  6c-benzoyl-2b,6b(45c)  as  a  o i l ( y i e l d 37%).  Hz, 2  (s,  MHz)  J = 5,2 H z , H]_), 5.65 J  mole)  photolyzed  complete  dihydrobenzo[a]cyclopropa[cd]pentalene-2a-carboxylate colorless  nm)  compounds  10'"^  were  e t h e r t o h e x a n e s as e l u e n t g a v e f o u r b a n d s .  benzophenone.  330  photoproducts.  On a p r e p a r a t i v e s c a l e , compound 45 and  the  (A >  excess  6:  (d,  IH,  isopropyl  Hz,  Hgb),  ester  1677  (s,  benzoyl  7.9-7.0 (m, 9H, a r o m a t i c ) , 5.90 J  =  5  methine),  1-15  C=0),  (d,  Hz, 4.46  3H,  J  Hg) , (s, =  6  4.96 IH,  C=0),  (dd, IH,  (septet,  Hgb),  4.28  IH, (d,  Hz,  methyl),  1.01  ( 1 2 ) , 152  ( 1 9 ) , 105  (100),  3H, J = 6 Hz, m e t h y l ) ppm. MS  ( E I ) m/e:  344  (M+,  3 ) , 284  ( 8 ) , 180  77 ( 2 7 ) . E x a c t mass c a l c u l a t e d f o r C23H20O3: 3 4 4 . 1 4 1 2 , f o u n d The 45d state  and  f o r t h b a n d c o n t a i n e d 5 mg 45e;  study.  these  two  of a 3 : 1 mixture  compounds  were  of  344.1406.  photoproducts  c h a r a c t e r i z e d i n the  solid  Solid  S t a t e P h o t o l y s i s o f Compound 45 Crystals  (A  of  45  > 330 nm) u n t i l  The  (A > 290 nm)  until  were  a  NMR  t o a 40  The  was  : 40  repeated  started  to  : 20 r a t i o  (A 15  reaction  >  290  nm)  and  photolyzed  45a  (DB-17)  at  a  27%  with a Pyrex f i l t e r  sleeve  melt.  showed  GC  (DB-17)  o f 45 ( 6 5 mg,  for  4  h  in  1.9 x 1 0 ' ^ m o l e )  two  NMR  tubes  with  m i n . The u n m e l t e d y e l l o w c r y s t a l s w e r e a n a l y z e d  mixture  a n d a 4 5 d : 45e was  d i e t h y l ether  and hexanes (1  inseparable  mixture  45d  of  together.  Data  : 45a r a t i o  chromatographed  eluting with  characterized  were  o f 45d, 45e, and 45a.  preparative scale, crystals  every  phototube  : 12 r a t i o o f 4 5 d , 4 5 e ,  t o show a 3 2 % c o n v e r s i o n  10.  analytical  the c r y s t a l s  photolyzed  rotating  : 44  photolysis  a 73% c o n v e r s i o n On  an  t h e c r y s t a l s w e r e y e l l o w b u t n o t m e l t e d . GC  a n a l y s i s s h o w e d a 44 conversion.  in  and for  45e  : (7.8  isopropyl  tetrahydrobenzo[a]cyclopropa[cd]pentalene-  9  o f 45  twice v/v). mg,  :  45  by :  on s i l i c a g e l The  yield  resulting 12%)  were  1-benzoyl-2a,2b,6b,6c-  2-carboxylate  (45d)  is  1^07  C=0),  1672  described. IR (s,  (neat,  benzoyl IR  45e), 45e),  4.41  (300  MHz)  J  =  7,7  ester  S : 7.6-6.7 (m, 9H, a r o m a t i c  ( s e p t e t , IR, J = 6 Hz, i s o p r o p y l (d,  IR,  J = 7 Hz, Hgb)>  o v e r l a p p i n g w i t h 4 3 ) , 3.40 J  (s,  C=0), 1270 ( s , C-0) c m " l .  NMR  4.78  50:50 m i x w i t h 4 5 e ) % a x =  Hz,  H2a),  = 6 Hz, m e t h y l )  1-01  3.61  methine  3R,  J  H2b),  with  overlapping  ( d d d , I H , J = 7,7,7  ( d d , I R , J = 7,7 H z , (d,  overlapping  3.00  = 6 Hz, m e t h y l ) ,  with  Hz,  (dd,  0.66  Hg^ IR,  ( d , 3H,  ppm.  GC-MS (DB-17, DCI i s o b u t a n e ) m/e:  345  (M+ + 1,  100),  285  (35).  E x a c t mass ( E I ) c a l c u l a t e d f o r C23H20O3: 3 4 4 . 1 4 1 2 , f o u n d Characterization  of  isopropyl  344.1405.  2-benzoyl-2a,2b,6b,6c-tetra-  h y d r o b e n z o [ a] c y c l o p r o p a [ c d ] p e n t a l e n e - 1 - c a r b o x y l a t e  (45e)  is  given  below. IR  ( n e a t , 50:50 m i x w i t h 45d) NMR  (300  S:  MHz)  u^^^^: s e e  7.6-6.7 (m,  above.  9H,  a r o m a t i c ) , 4.62  I H , J = 6 Hz,  i s o p r o p y l methine o v e r l a p p i n g w i t h  J  Hgb).  =  45d), 0.88  7  Hz,  3.31  3.58  (ddd,  ( d d , I H , J = 7,7  ( d , 3H,  J = 6 Hz,  GC-MS  (DB-17,  Hz,  I H , J = 7,7,7 H2b).  m e t h y l ) , 0.44 DCI  3.20  Hz,  Hg^  4.33  J = 6 Hz,  345  (M+  Small  amounts  acetonitrile,  of  and  45a  On and  a  -l- 1,  analyzed  by  (A  NMR  Isopropyl  J  = 3 Hz,  IH,  Hgb),  > (GC)  ppm.  100),  285  (52).  344.1418.  dissolved (A  one  >  in  290  product  benzene,  nm)  (45f)  showed  at  a  13%  10 mg  290  o f 45a w e r e d i s s o l v e d  nm)  to  t o g i v e a 45a  i n 1 ml  equilibrium.  The  to 45f r a t i o  o f 88  o f CDCI3  mixture (91)  was  : 12 ( 9 ) .  1-benzoyl-2b,6b-dihydrobenzo[a]cyclopropa[cd]pentalene-  6c(2aH)-carboxylate ^H  H2a),  GC.  larger scale,  photolyzed  were  Photolysis  a s o l v e n t - i n d e p e n d e n t r e a c t i o n to form maximum c o n v e r s i o n b y  IH,  45a  compound  acetone.  Hz,  methyl)  E x a c t mass ( E I ) c a l c u l a t e d f o r C23H20O3: 3 4 4 . 1 4 1 2 , f o u n d  Photolysis of Benzosemibullvalene  (d,  overlapping with  ( d d , I H , J = 7,7  ( d , 3H,  i s o b u t a n e ) m/e:  45d),  (septet,  NMR  (300  H2),  5.06  3.95  ( 4 5 f ) was MHz)  5:  (septet,  characterized 7.9-7.1  (m,  I H , J = 6 Hz,  ( d , I H , J = 8 Hz,  H2b),  in this 9H,  mixture.  a r o m a t i c ) , 5.94  isopropyl methine),  3.50  ( d d , I H , J = 8,3  (d, IH, 4.94  (s,  Hz,  H2a)  ppm.  Methyls of the i s o p r o p y l are hidden beneath GC-MS (DB-1, E I ) m/e:  152  (13),  105  (100),  344.1412, f o u n d  Photolysis On  conversion  220  H.  (19).  8 ) , 302  ( 8 ) , 284  257  (10),  344.1400.  and  a c e t o n e . The  product of  (8),  E x a c t mass c a l c u l a t e d f o r C23H20O3:  45c  a n a n a l y t i c a l s c a l e , compound 4 5 c was  one  t o 45b  77  (M+,  of Benzosemibullvalene  acetonitrile, to give  344  45a.  i n t h e gas  It  was  in  benzene,  s o l u t i o n s w e r e p h o t o l y z e d (A > 290  (45b), independent  87%.  dissolved  of solvent,  also noticed  chromatography  that  at  an  equilibrium  compound 4 5 c  c o l u m n (DB-17) a t  nm)  rearranges  temperatures  above  °C.  1,4-Dihydro-l,4-ethenonaphthalene-2,3-dicarboxylate  Direct  Solution Photolysis A  salts  standard  ( 4 8 - 5 4 ) was  suitable  The  procedure adopted.  deuterated  s a m p l e was  degassed  ratios  of  of S a l t s  48-54  for analytical photolysis  The  solvent  by  Salts  salt (1  repeating  photoproducts  (5 - 10 mg)  was  dissolved  ml)  i n a 10 m l  the  freeze-pump-thaw  ( d e t e r m i n e d b y NMR)  o f the  prepared with  Pyrex phototube. cycle  were r e p o r t e d  a The  twice. i n the  text. On 48-54 solvent  a  was  preparative to dissolve  (3 m l )  photolyzed  and  scale, 10  - 30 mg  i n a 10 m l P y r e x the  the  resulting  standard  o f the s a l t  phototube. mixture  procedure  for  salts  i n a suitable deuterated  The  degassed  sample  was  a n a l y z e d d i r e c t l y b y NMR.  The  r a t i o s were r e p o r t e d i n t h e t e x t .  The m i x t u r e  diethyl  HCl  over  ether,  MgSO^,  resulting and  acidified  filtered,  mixture  (aq)>  evaporated,  of  reported  and  State Photolysis of Salts Crystals  placed the  or  powders  ratios  the text.  and  (approx.  w i t h water,  dried  in  CDCI3.  The  (400  MHz)  assignments.  10  mg)  of  salts  48-54  tube and p h o t o l y z e d . A f t e r solvent  resultant  For each s a l t ,  with  48-54  i n a n i t r o g e n - f i l l e d NMR  product  washed  diluted  d i a c i d s was a n a l y z e d b y NMR  s a m p l e was d i s s o l v e d i n a s u i t a b l e  The  then  redissolved  the s i g n a l s c o r r e l a t e d to confirm our  Solid  in  with  was  the  and  were  irradiation  analyzed  by  NMR.  sample appearances were t a b u l a t e d  same  procedure  was  repeated  using  several d i f f e r e n t p h o t o l y s i s times.  I . D ime t h y 1 1,4-D ime t h y 1 - 1 , 4 , 5 , 8 - 1 e t r a m e t h y 1 - 1 , 4 - e t h e n o n a p h t h a 1 e n e - 2 , 3 dicarboxylate  (47)  D i r e c t S o l u t i o n P h o t o l y s i s o f Compound 47 On a n a n a l y t i c a l (A  >  290  nm)  formation at  an  of  in two  scale,  c r y s t a l s o f compound  benzene and a c e t o n i t r i l e . products,  approximate  1  :  1  47b ratio.  c h a n g e d ; 47b s t a r t e d t o d i m i n i s h photoproduct In were  an  was s e e n NMR  photolyzed  47a,  At  and  photolyzed  GC m o n i t o r i n g independent  higher  the  were  showed t h e of  conversions  formation  of  a  solvent the r a t i o secondary  (47c).  study, (A  and  47  >  crystals 290  nm)  of for  47 30  dissolved min.  The  i n 1.5 m l  CDCI3  mixture  was  analyzed at  by  NMR  (GC)  to  a  47b  :  47a  ratio  9% c o n v e r s i o n . A p r e p a r a t i v e r e a c t i o n was p e r f o r m e d w i t h  of  compound  and  photolyzed  mixture  on  47  in  silica  dimethyl  five  10 m l p h o t o t u b e s ,  gel three  bands.  The  94-98 °C.  IR  ( K B r ) v^^^:  IR  NMR  band  (47c)  as  a  white  19.4  (1 : 9 v/v)  contained  ( 4 0 0 MHz) 6: 6.95  3.36  (s,  methyl),  NMR  (50  solid  23  mg  (yield  9%).  IH, 1.78  3H,  (AB q u a r t e t , 2H, J = 14,8 H z , a r o m a t i c ) , ester  methyl),  3.78  Hg^)> 2.21 ( s , 3H, a r o m a t i c ( s , 3H, m e t h y l  (s,  3H,  methyl),  o n C ^ ) , 1.25  (s,  b y NOE  ester  2.19 ( s ,  3H,  methyl  studies.  MHz) 5: 171.0 ( C = 0 ) , 170.5 ( C = 0 ) , 148.3 ( C ) , 1 4 7 . 1  134.5 ( C ) , 133.9 ( C ) , 129.4 ( C H ) , 129.3 ( C H ) ,  (CH),  the  prisms.  o n C2a) ppm. The a b o v e a s s i g n m e n t s w e r e s u p p o r t e d  (C),  of  1730 ( v s , C = 0 ) , 1274 ( s , C - 0 ) , 1244 ( s ) cm"!.  5.08 ( s , I H , H 2 ) , 3.82 ( s ,  l^c  mmole)  2a,6c - d i h y d r o - 1 , 2 a , 3 , 6 - t e t r a m e t h y l b e n z o [ a ] c y c l o p r o p a [ c d ] -  MP:  aromatic  (0.77  Chromatography  first  R e c r y s t a l l i z a t i o n from hexanes gave c o l o r l e s s  3H,  mg  u s i n g a d i e t h y l e t h e r and hexanes  pentalene-2b,6b-dicarboxylate  methyl),  250  u s i n g benzene as s o l v e n t ,  (A > 290 nm) t o 9 5 % c o n v e r s i o n .  s o l v e n t s y s t e m gave of  o f 43 ( 4 1 ) : 57 ( 5 9 )  128.2  (CH),  73.5 ( C ) , 65.1 ( C ) , 53.0 ( C ) , 5 2 . 1 ( C H 3 ) , 51.7 ( C H 3 ) , 4 7 . 4 ( C H 3 ) , 19.2 ( C H 3 ) , 13.8 ( C H 3 ) , 12.0  (CH3)  ppm.  The  120.3 (CH3),  assignments  w e r e b a s e d u p o n a n APT. MS (100).  ( E I ) m/e:  326  (M+,  5 5 ) , 294 ( 7 4 ) , 267 ( 6 3 ) , 235 ( 4 1 ) , 207  E x a c t mass c a l c u l a t e d f o r C20H22O4: 3 2 6 . 1 5 1 8 , f o u n d Anal, calcd.  H, 6.76.  f o r C20H22O4: C, 7 3 . 6 0 ;  H,6.79.  Found:  326.1512. C,  73.50;  The  second  b a n d was 58 mg o f d i m e t h y l  c y c l o o c t e n e - 5 , 1 0 - d i c a r b o x y l a t e (47b) as R e c r y s t a l l i z a t i o n from  a  1,4,6,9-tetramethylbenzo-  white  m e t h a n o l gave c o l o r l e s s  solid  (yield  23%).  rods.  MP: 204-207 °C. IR  (KBr)  1 7 1 1 ( s , C = 0 ) , 1620 ( m ) , 1239 ( s , C-0) cm'^.  Uma^:  NMR  ( 4 0 0 MHz) 5: 6.98 ( s , 2H, a r o m a t i c ) , 5.88 ( s , 2H, v i n y l ) ,  3.65 ( s , 6H, e s t e r m e t h y l s ) , (s,  6H, v i n y l m e t h y l s )  2.21 ( s , 6H, a r o m a t i c  ppm. T h e s e a s s i g n m e n t s  methyls),  were  2.06  supported  by  NOE  studies. NMR (2  X  (100  C ) , 1 3 3 . 1 (2  51.6  (2  x  MHz)  6:  167.4  (2  x C=0) , 1 4 8 . 5 (2 x C) , 138.4  C ) , 133.0 (2 x C H ) , 129.7 (2 x C ) , 128.5 (2 x  X  ester  CH),  C H 3 ) , 19.7 (2 x C H 3 ) , 19.6 (2 x CH3) ppm. The a b o v e  a s s i g n m e n t s w e r e b a s e d o n a n APT. MS (100).  ( E I ) m/e:  326 (M+, 3 5 ) , 294 ( 8 0 ) ,  267  ( 6 4 ) , 235  E x a c t mass c a l c u l a t e d f o r C20H22O4: 3 2 6 . 1 5 1 8 , f o u n d Anal.  calcd.  ( 4 3 ) , 207 326.1518.  f o r C20H22O4: 0, 7 3 . 6 0 ; H, 6.79. F o u n d : C, 7 3 . 7 0 ;  H, 6.72. The  structure  diffraction  of  analysis.  orthorhombic,  space  this  The  group  compound  crystal Pbca,  a  was  data =  confirmed  are  as  by  an  follows:  17.716(2)Â,  b  =  X-ray  C20H22O4,  15.298(2)Â,  c = 13.210(3)Â, V = 3 5 8 0 ( 2 )  3 , Z = 8, D^^ = 1.211 g / m l , R = 0.046. The  third  b a n d was d i m e t h y l  2a,2b-dihydro-1,2b,3,6-tetramethyl-  benzo[a]cyclopropa[cd]pentalene-6b,6c-dicarboxylate some and  unreacted  starting  material  ( 4 7 ) . The m i x t u r e  c h r o m a t o g r a p h e d a s a b o v e t o g i v e 33 mg o f  (yield  (47a) mixed  47a  as  was a  1 3 % ) . R e c r y s t a l l i z a t i o n from hexanes gave c o l o r l e s s  with  rephotolyzed white prisms.  solid  MP: 104-105 °C. IR  ( K B r ) v^^^: 1734 ( s , C = 0 ) , 1435 ( m ) , 1 2 7 2 ( s , C-0) cm-1.  IR  NMR  S:  ( 4 0 0 MRz)  6 . 9 2 ( s , 2H,  aromatic),  5.04(d, IR,  J - 2 H z , H 2 ) , 3.83 ( s , 3H, e s t e r m e t h y l ) , 3.67 ( s , 3H, e s t e r 3.04  (d, IH, J  =  2  H z , H 2 a ) , 2.41 ( s , 3H, a r o m a t i c m e t h y l ) , 2.25  ( s , 3H, a r o m a t i c m e t h y l ) , 1.94 ( s , 3R, m e t h y l ) , 1.81 ppm. T h e a b o v e a s s i g n m e n t s l^c  NMR  20.7  ( s , 3H,  methyl)  w e r e s u p p o r t e d b y NOE s t u d i e s .  ( 1 0 0 MHz) 5:  171.1 ( C = 0 ) , 169.5 ( C = 0 ) ,  ( C ) , 137.0 ( C ) , 1 3 2 . 9 ( C ) , 130.4 ( C H ) , 1 2 9 . 4 ( C H ) , (CH),  methyl),  146.7 ( C ) , 145.9  128.3  120.0  (CH),  70.0 ( C ) , 68.3 ( C ) , 53.0 ( C ) , 5 1 . 9 ( e s t e r C H 3 ) , 51.0 ( e s t e r C R 3 ) , (CH3),  were based MS  1 9 . 8 (CH3),  17.3 ( C R 3 ) ,  13.9 (CH3) ppm.  These  assignments  o n a n APT e x p e r i m e n t . ( E I ) m/e  326 (M+, 3 5 ) , 294 ( 2 7 ) , 266 ( 1 0 0 ) ,  mass c a l c u l a t e d f o r C20H22O4: 326.1518, f o u n d Anal, calcd.  207 ( 8 4 ) . Exact  326.1527.  f o r C20H22O4: C, 79.60; R, 6.79.  Found:  C,  73.80;  H, 6.86. The  structure  was  confirmed  diffraction analysis.  The d a t a a r e a s f o l l o w s :  C2oH2204>  space  a  group  Pca2i,  of  this  =  compound  7.325(9)Â,  an  orthorhombic,  0.045.  Details  will  be  Photolysis  analytical  approximately photolyzed  X-ray  elsewhere.  Benzophenone-Sensitized In  an  b = 14.781(1)Â, c = 15.535(1)Â,  V = 1681.9(5)Â3, Z = 4 , D^^ = 1.289 g / m l , R = published  by  (A  2-fold >  w/w  study, excess  compound  47  was  o f benzophenone  330 nm) t o c o m p l e t e  dissolved  with an  i n benzene  c o n v e r s i o n . GC m o n i t o r i n g  and showed  two p r o d u c t s ,  47a a n d 47d, a t a 32 : 68 r a t i o .  On a l a r g e r s c a l e , benzophenone  crystals  of  47  silica  g e l using  diethyl  ether  :  60  ratio.  mmole)  n o t be  separated  From t h e m i x t u r e ,  and  and  (A > 330 nm)  Chromatography  a n d h e x a n e s ( 1 : 19 v / v ) a s t h e  e l u e n t s e p a r a t e d b e n z o p h e n o n e f r o m 47a a n d 47d. The could  0.25  ( 2 0 0 mg) i n 8 m l o f b e n z e n e w e r e p h o t o l y z e d  t o 9 2 % c o n v e r s i o n t o 47a a n d 47d i n a 4 0 on  ( 8 0 mg,  therefore  two  photoproducts  47d c o u l d n o t b e i d e n t i f i e d .  t h e f o l l o w i n g GC-MS d a t a c o u l d b e o b t a i n e d :  GC-MS ( D B - 1 , E I ) m/e: 326 (M+, 1 2 ) , 266 ( 1 0 0 ) ,  235 ( 1 4 ) , 207 ( 8 0 ) ,  193 ( 2 9 ) . When to other  left  to  inseparable  stand,  i t was n o t i c e d t h a t 47d r e a d i l y  converted  products.  S o l i d S t a t e P h o t o l y s i s o f Compound 47  tube  C r y s t a l s o f 47 (8 mg) w e r e p h o t o l y z e d  (A >  f o r 15  c o l o r l e s s b u t were  h.  The  crystals  remained  290  nm)  i n an  s t i c k y o n t h e s u r f a c e . NMR a n a l y s i s showed t h e f o r m a t i o n o f photoproduct  (47a).  The  The p h o t o l y s i s was r e p e a t e d  ratio  of  f o r 45  47 h  : and  s t i c k y c r y s t a l s h a d a 47 : 47a : 47b r a t i o Crystals  of  47  were p h o t o l y z e d  NMR  slightly  one  major  47a : 47b was 89 : 10 : 1. the colorless,  slightly  o f 79 : 20 : 1.  (A > 330 nm) f o r 4 d a y s t o g i v e  b y NMR a 47 : 47a : 47b r a t i o o f 94 : 6 : t r a c e . C r y s t a l s were a l s o p h o t o l y z e d w i t h a n i t r o g e n l a s e r for  5  h.  NMR  analysis  of  s h o w e d a 47, 47a, a n d 47b r a t i o  the unmelted c o l o r l e s s o f 76 : 23 : 1.  (A = 337  crystals  nm)  i n CDCI3  Photolysis  of Cyclooctatetraene  47b  On a n a n a l y t i c a l s c a l e , c r y s t a l s o f 47b in  benzene  showed  the  and  acetone.  formation  of  much f a s t e r t h a n t h e b e n z e n e  Photolysis compound reaction.  (5  mg)  (A > 290 nm) 47c.  The  were  with  acetone  GC  dissolved monitoring  reaction  was  III.  QUANTUM Y I E L D STUDIES  Apparatus A to  merry-go-round  450  W  the l i g h t  Hanovia  source.  filter  aqueous  medium  The  313  combination  solution  circulated  of  through  nm of  0.002  Benzene B e n z e n e was sulfuric  a Pyrex  was  prior  acid  to  used  a l a r g e water  (<  were  alkane  K2Cr04  lamp  lamp glass  containing  +  3  was  was  used  as  isolated  by  plate^^S  5%  °C).  ^nd  K2CO3  an  (wt/wt)  jacket.  the  solvent  by  unless  successive  by  purified  internal  Corning  GC). by  The  was  (from  with  over  starting  for  Aldrich)  metal.122  acetophenone  materials and  specified.  concentrated  sodium  checked  chromatography  standards  otherwise  washes  distillation  actinometer,  0.3%  the  (20  bath  Reagents  as  u s e d as t h e  and  their  recrystallization. were  used  with  no  purification.  I n t e r n a l Standards Each  or  in  mercury  from  7-54  cooling  followed  use  photoproducts  further  a  made t h i o p h e n e - f r e e b y  Valerophenone,  GC  used  pressure line  M  P u r i f i c a t i o n o f S o l v e n t s and  The  ^^s  m a i n t a i n an e v e n p h o t o l y s i s a t a c o n s t a n t t e m p e r a t u r e  The  a  apparatus-'-23  signal  and  alkane was  GC  Detector  internal  close  but  (FID)  standard did  not  Responses chosen  was  such  that  its  o v e r l a p w i t h the s t a r t i n g m a t e r i a l  i t s photoproducts. Tetradecane  valerophenone  (n-Cii^ti^Q)  actinometry.  was  the  Tetracosane  internal (n-C24H5Q)  standard was  the  for  the  internal  s t a n d a r d f o r the photoproducts Tricosane 45, of  (n-C23H4g)  and  octacosane  starting  injections internal  was  of s t a r t i n g  the i n t e r n a l  (n-C28H58)  material  44.  materials  42,  43,  and  47.  standard f o r the photoproducts  internally  standardized  of  the  study  D e t e c t o r responses were measured from  several  ( n > 3) o f a n a c c u r a t e l y w e i g h e d m i x t u r e o f  photoproduct  and  standard.  Actinometry Valerophenone  actinometry  o f acetophenone from valerophenone with The  an  excitation  benzene were  opaque  concentration wavelength  solutions  degassed  by  nitrogen.  These  alongside  the  m o n i t o r e d b y GC  of  repeating  (carbowax  M)  quantum to  nm  valerophenone  and  1 g/ml  freeze-pump-thaw 10  in  ml  the  c o l u m n , 15 m,  be  of valerophenone 313  in  samples  The  mercury  the  solutions, test  the  M  used.  has been e s t a b l i s h e d  (0.1  was  0.1  was  Pyrex  0.3  Two  3  ml  of tetradecane  cycle  o f two  =  i n b e n z e n e . •'-^^  twice  phototubes,  average  $  line.  merry-go-round  yield  under  were p l a c e d  apparatus  and  injections).  Irradiations Two  3 ml t e s t samples were p r e p a r e d f o r each  o p a q u e c o n c e n t r a t i o n a t 313 Internal  standards  samples  was  samples  were  m o n i t o r e d b y GC  were  nm, added  approximately photolyzed (DB-1, 15 m,  t h a n 10% p h o t o p r o d u c t  d e t e r m i n e d b y UV  5%  and of  alongside two  formation.  their the the  starting material.  studies,  was  concentration starting actinometer  in  An  prepared. the  material. solutions  i n j e c t i o n s p e r s a m p l e p o i n t ) t o no  test The and more  C a l c u l a t i o n o f Quantum Y i e l d s After  correcting  for  the  v a r i o u s r e s p o n s e s , t h e quantum  yields  were c a l c u l a t e d from the f o l l o w i n g e q u a t i o n : ^ '  $ = # moles photoproduct / # moles photons  The  quantum y i e l d  conversions to  zero  were on  and  error  of  limits  B.  each  graphed  conversion  determined one  of  by  to  photoproduct (in  text).  determine linear  Clifford's  was  The  the  least  calculated  straight reported  squares  undergraduate  absorbed  l i n e was value.  different  extrapolated These  calculations  laboratory  a r e r e p o r t e d as s t a n d a r d d e v i a t i o n s ,  at  values  performed  computers.  i n parentheses.  The  REFERENCES  1. R o t h , H.D. A n g r e w . Chem. E d . E n g l . 1989, 2 8 , 1 1 9 3 - 1 2 0 7 . 2. R a m a m u r t h y , V. " P h o t o c h e m i s t r y i n O r g a n i z e d a n d C o n s t r a i n e d M e d i a " , VCH P u b l i s h e r s C o . , New Y o r k , 1991. 3. W o h l e r , 4. a ) b) c) d) 5.  F. P r o g g . A n n . 1828, 1 2 , 2 5 3 .  C i a m i c i a n , G.; S i l b e r , P. Chem. B e r . 1901, 34, 2 0 4 0 - 2 0 4 6 . K o h l s h u t t e r , H.W. Z. A n o r g . A l l g . Chem. 1918, 1 0 5 , 1 2 1 . S t o b b e , H.; S t e i n b e r g e r , F.K. Chem. B e r . 1922, 5 5 , 2 2 2 5 - 2 2 4 5 . S e n i e r , A.; S h e p h e a r d , F.G. J . Chem. S o c . 1909, 9 5 , 1 9 4 3 - 1 9 5 5 .  a ) D e s i r a j u , G.R. " O r g a n i c S o l i d S t a t e C h e m i s t r y " , E l s e v i e r , A m s t e r d a m , 1987. b ) S c h e f f e r , J.R.; T r o t t e r , J . ; G a r c i a - G a r i b a y , M.; W i r e k o , F. M o l . C r y s t . L i q . C r y s t . I n c . N o n l l n . O p t . 1988, 1 5 6 , 6 3 . c ) A n p o , M.; M a t s u u r a , T. " P h o t o c h e m i s t r y o n S o l i d S u r f a c e s " , E l s e v i e r , A m s t e r d a m , 1989. d) S c h e f f e r , J.R.; G a r c i a - G a r i b a y , M.; N a l a m a s u , 0. i n " O r g a n i c P h o t o c h e m i s t r y " , Padwa, A., M a r c e l D e k k e r , New Y o r k , 1987, Ch. 8, V o l . 4. e) D e s i r a j u , G.R. " C r y s t a l E n g i n e e r i n g : The D e s i g n o f O r g a n i c S o l i d s " , E l s e v i e r , New Y o r k , 1989.  6. T u r r o , N . J . " M o d e r n M o l e c u l a r P h o t o c h e m i s t r y " , M e n l o P a r k , 1978.  Benjamin/Cummings,  7. De Mayo, P., E d . " R e a r r a n g e m e n t s i n G r o u n d a n d E x c i t e d S t a t e s " , V o l 3, A c a d e m i c , New Y o r k , 1980. 8. a ) K e l l e r , R.A.; D o l b y , L . J . J . Am. Chem. S o c . 1969, 9 1 , 1 2 9 3 . b ) B r e e n , D.E.; K e l l e r , R.A. J . Am. Chem. S o c . 1968, 9 0 , 1 9 3 5 . 9. G a r c i a - G a r i b a y , M.; S c h e f f e r , J.R.; T r o t t e r , J . ; W i r e k o , T e t r a h e d r o n L e t t . 1987, 2 8 , 1 7 4 1 . 10.  For a review see: Hixson, Mariano, pp 5 3 1 - 5 5 1 .  11. M e i n w a l d ,  J . ; S z k r y b a l o , W.;  F.  a n d Zimmerman Chem. R e v . 1973, 73,,  D i m m e l , D.R. T e t r a h e d r o n L e t t .  1967, 7 3 1 .  12.  a ) Zimmerman, H.E.; G r u n e w a l d , G.L. J . Am. Chem. S o c . 1966, 8 8 , 1 8 3 . b ) Zimmerman, H.E.; B i n k l e y , R.W.; G i v e n s , R.S.; S h e r w i n , M.A. J . Am. Chem. S o c . 1967, 8 9 , 3932.  13.  P a q u e t t e , L.; V a r a d a r a j a n , A.; B u r k e , 8032.  L.D. J . Am. Chem. S o c . 1986, 1 0 8 .  14. T u r r o , N . J . " M o d e r n M o l e c u l a r P h o t o c h e m i s t r y " , Menlo P a r k , 1978, pp.488-489. 15.  Benjamin/Cummings,  Zimmerman, H.E.; P r a t t , A.C. J . Am. Chem. S o c . 1 9 7 0 , 9 2 , 6 2 6 7 .  16. H i x s o n , S.S. J . Am. Chem. S o c . 1 9 7 2 , 9 4 , 2 5 0 7 . 17.  Zimmerman, H.E.; B i n k l e y , R.W.: G i v e n s , R.S.: S h e r w i n , M.A. J . Am. Chem. S o c . 1 9 6 7 , 8 9 . 3 9 3 2 .  18.  Edman, J . R . J . Am. Chem. S o c . 1 9 6 9 , 9 1 .  19.  a ) Hammond. G.S.; S a l t i e l , J . J . Am. Chem. S o c . 1 9 6 3 , 8 5 , 2 5 1 6 . b ) H e r k s t r o e t e r , W.G.; Hammond, G.S. J . Am. Chem. S o c . 1 9 6 6 , 8 8 , 4 7 6 9 .  20.  a ) Zimmerman, H.E.; Kamm, K.S.; W e r t h e m a n , D.P. J . Am. Chem. S o c . 1 9 7 5 , 97. 3 7 1 8 . b ) B o n n e a u , R.; J o u s s o t - D u b i e n , J . ; S a l e m , L . ; Y a r w o o d , A . J . J . Am. Chem. S o c . 1 9 7 6 , 9 8 , 4 3 2 9 . c ) B o n n e a u , R.; J o u s s o t - D u b i e n , J . ; S a l e m , L . ; Y a r w o o d , A . J . T e t r a h e d r o n L e t t . 1977, 235.  7103.  2 1 . a ) De Mayo, P. " R e a r r a n g e m e n t s i n G r o u n d a n d E x c i t e d S t a t e s " , V o l . 3, A c a d e m i c , New Y o r k , 1 9 8 0 , p 1 3 7 . b ) Zimmerman, H.E. i n " O r g a n i c P h o t o c h e m i s t r y " Padwa, A. e d . , V o l . 1 1 , M a r c e l D e k k e r , New Y o r k , 1991, p 25. 22. G r i f f i n , G.W.; 1965, 2951. 23.  Zimmerman, H.E.; T o l b e r t ,  24. C i g a n e k , 25.  M a r c a n t o n i o , A.P.; K r i s t i n s s o n ,  H. T e t r a h e d r o n  Lett.  L.M. J . Am. Chem. S o c . 1 9 7 5 , 9 7 , 5 4 9 7 .  E. J . Am. Chem. S o c . 1 9 6 6 , 8 8 , 2 8 8 2 .  a ) Zimmerman, 96. 4 3 9 . b ) Zimmerman. 1978, 100, c ) Zimmerman,  H.E.; W e r t h m a n n , D.P.; Kamm, K.S. J . Am. Chem. S o c . H.E.; S t e i n m e t z , M.G.; K r e i l , C.L. J . Am. Chem. S o c . 4146. H.E.; K l u m , R.T. T e t r a h e d r o n 1 9 7 8 , 3 4 , 1 7 7 5 .  26. De Mayo, P. " R e a r r a n g e m e n t s i n G r o u n d a n d E x c i t e d S t a t e s " , V o l . 3, A c a d e m i c , New Y o r k , 1 9 8 0 , p p . 1 5 3 - 1 5 8 . 27.  C o h e n , M.D.; S c h m i d t ,  G.M.J. J . Chem. S o c . 1 9 6 4 ,  1996.  28.  S c h m i d t , G.M.J, i n " S o l i d S t a t e P h o t o c h e m i s t r y " , D. G i n s b u r g , E d . , V e r l a g C h e m i e , New Y o r k , 1 9 7 6 .  29.  S t o u t , G.H.; J e n s e n , L.H. " X - r a y S t r u c t u r e D e t e r m i n a t i o n " , 2 n d e d , W i l e y , New Y o r k , 1 9 8 9 , p p . 1-7.  30.  F y f e . C A . " S o l i d S t a t e NMR f o r C h e m i s t s " , 1983.  C.F.C. P r e s s ,  Guelph,  1974,  31. Blazek, A. "Thermal Analysis", V.N.R. Co., London, 1 9 7 3 , p 152. 32. a) Cohen, M.D. Angew. Chem.. Int. Ed. Eng. 1 9 7 5 , 14, 386. b) Cohen, M.D. Mol. Crvst. L i g . Crvst. 1 9 7 9 , 50, 1. 33. Lahav, M. i n "Photochemistry i n Organized and Constrained Media", Ramamurthy, V. Ed., VCH Publishers Co., New York, 1 9 9 1 , pp. 247-302. 34. For a recent publication see: McBride, J.M.; Carter, R.L. Angew. Chem. 1 9 9 1 , 103, 298. 35. Scheffer, J.R. i n "Photochemistry i n Organized and Constrained Media", Ramamurthy, V. Ed., VCH Publishers Co., New York, 1 9 9 1 , pp. 185-246. 36. Ramamurthy, V. i n "Photochemistry i n Organized and Constrained Media", Ramamurthy, V. Ed., VCH Publishers Co., New York, 1 9 9 1 . 37. Appel, W.K.; Greenhough, T.J.; Scheffer, J.R.; Trotter, J . J . Am. Chem. Soc. 1 9 7 9 , 101, 213. 38. De Mayo, P. "Rearrangements i n Ground and Excited States", V o l . 3, Academic, New York, 1 9 8 0 , p 255. 39. Pokkuluri, P.R.; Scheffer, J.R.; Trotter, J . Tetrahedron L e t t . 1 9 8 9 , 1601. 40. Wegner, G. Pure  APPI.  Chem.  1977,  49, 443.  41. a) Nakanishi, H.; Jones, W.; Thomas, J.M.; Hursthouse, M.B.; Motevalli, M. J . Chem. Soc. Chem. Commun. 1 9 8 0 , 611. b) Jones, W.; Nakanishi, H.; Theocharis, C.R.; Thomas, J.M. J . Chem. Soc. chem. Commun. 1 9 8 0 , 610. c) Nakanishi, H.; Jones, W.; Thomas, J.M.; Hursthouse, M.B.; Motevalli, M. J . Phvs. Chem. 1 9 8 1 , 85/ 3636. 42. Evans, S.V.; Garcia-Garibay, M.; Nalamasu, O.; Scheffer, J.R,; Trotter, J . J . Am. Chem. Soc. 1 9 8 6 , 108, 5648. 43. A l l i n g e r , N.L.; Flanagan, H.L. J . Comput. Chem. 1 9 8 3 , 4, 399. 44. Zimmerman, H.E.; Zuraw, M.J. J . Am. Chem. Soc. 1 9 8 9 , 111. 7974. 45. S t i l l , C.W.; Mohamadi, F.; Richards, N.G.J.; Guida, W.C.; Caufield, C ; Liskamp, R.; Hendrickson, T.; Chang, G. "MacroModel", Version 2.0, Columbia University, New York, New York 10027. 46. Carey, F.A.; Sundberg, R.J. "Advanced Organic Chemistry", Part A, Plenum/Rosetta, New York, 1 9 7 7 , Chapter 10. 47. Woodward, R.B.; Hoffmann, R. "Conservation of O r b i t a l Symmetry", Academic, New York, 1 9 7 0 .  48. a) Paquette, L.A.; Mecham, G.V. J . Org. Chem. 1 9 6 9 , 34, 450. b) Furntachi, N.; Nakadaira, Y.; Nakanishi, K. J . Am. Chem. Soc. 1 9 6 9 , 91, 1028. 49. Turro, N.J. " Modern Molecular Photochemistry", Menlo Park, 1 9 7 8 , p 540.  Benjamin/Cummings,  50. a) Engel, P.S.; Schnexnaayder, M.A. J . Am. Chem. Soc. 1 9 7 2 , 94, 9252. b) Engel, P.S.; Schnexnaayder, M.A. J . Am. Chem. Soc. 1 9 7 5 , 97, 145. 51. Dolphin, D.; Wick, A. "Tabulation of Infrared Spectral Data", Wiley Interscience, New York, 1 9 7 7 , 408. 52. a) Dauben, W.G.; Koch, K.; Smith, S.L.; Chapman, O.L. J . Am. Chem. Soc. 1 9 6 3 , 85/ 2616. b) Dauben, W.G.; Koch, K.; Smith, S.L.; Chapman, O.L. J . Am. Chem. Soc. 1 9 6 1 , 83/ 1768. 53. Bender, CO.; Wilson, J . Helv. Chim. Acta. 1 9 7 6 , 59, 1469. 54. Bender, CO.; Brooks, D.W.; Cheng, W. ; Dolman, D.; O'Shea, S.F.; Shugarman, S.S. Can. J . Chem. 1 9 7 8 , 5^, 3027. 55. Bender, CO.; Bengston, D.L.; Dolman, D.; Herle, CE.L.; O'Shea, S.F. Can. J . Chem. 1 9 8 2 , 60, 1942. 56. a) Evans, S.V.; Garcia-Garibay, M.; Omkaram, N.; Scheffer, J.R.; Trotter, J . ; Wireko, F. J . Am. Chem. Soc. 1 9 8 6 , 108. 5648. b) Garcia-Garibay, M.; Scheffer, J.R.; Trotter, J . ; Wireko, F. Tetrahedron Lett. 1 9 8 7 , 4789. c) Garcia-Garibay, M.; Scheffer, J.R.; Trotter, J . ; Wireko, F. Tetrahedron Lett. 1 9 8 8 , 2041. d) Scheffer, J.R.; Trotter, J . ; Garcia-Garibay, M.; Wireko, F. Mol. Cryst. Inc. Nonlin. Opt. 1 9 8 8 , 156, 63. 57. Kitahonoki, K.; Takano, Y. Tetrahedron L e t t . 1 9 6 3 , 1597. 58. Friedman, L. J . Am. Chem. Soc. 1 9 6 7 , 89, 3071. 59. Zimmerman, H.E.; Givens, R.S.; Pagni, R.M. J . Am. Chem. Soc. 1 9 6 8 , 90, 6096. 60. Grovenstein, E., J r . ; Campbell, T . C ; Shibata, T. J . Org. Chem. 1 9 6 9 , 34/ 2418. 61. Brewer, J . ; Heaney, H. J . Chem. Soc. Chem. Commun. 1 9 6 7 , 811. 62. Zimmerman, H.E.; Bender, C O . J . Am. Chem. Soc. 1 9 7 0 , 92., 4366. 63. Bender, CO.; Shugarman, S.S. J . Chem. Soc. Chem. Commun. 1 9 7 4 , 934. 64. Bender, CO.; Wilson, J . Helv. Chim. Acta. 1 9 7 6 , 59, 1469.  65. Bender, CO.; Bengtson, D.L.; Dolman, D.; Herle, C.E.L.; O'Shea, S.P. Can. J . Chem. 1 9 8 2 , 60/ 1942. 66. Bender, CO.; Cassia, I.M.; Dolman, D.; Heerze, L.D.; Schultz, F.L. Can. J . Chem. 1 9 8 4 , 62, 2769. 67. Bender, CO.; Dolman, D.; Murphy, G.K. Can. J . Chem. 1 9 8 8 , 66, 1656. 68. Bender, CO.; Clyne, D.S.; Dolman, D. Can. J . Chem. 1 9 9 1 , 69, 70. 69. To the best of the author's knowledge, there has been no other reports on the photochemistry of benzobarrelenes i n organized media. 70. The subject reaction i s more appropriately termed "tri-T-dimethane". However, the text term i s used i n order to be consistent with previous l i t e r a t u r e reports. 71. Pokkuluri, P.R.; Scheffer, J.R.; Trotter, J . J . Am. Chem. Soc. 1 9 9 0 , 112/ 3676. 72. Diels, O.; Alder, K. Justus Liebiqs Ann. Chem. 1 9 3 1 , 486. 191. 73. March, J . "Advanced Organic Chemistry", 3rd ed., John Wiley and Sons, New York, 1 9 8 5 , p 747. 74. Goubeau, J . ; Luther, H.; Feldmann, K.; Brandes, G. Chem. Ber. 1 9 5 3 , 86/ 214. 75. a) Lutz, R.E.; Smithey, W.R., J r . J . Org. Chem. 1 9 5 1 , ^6, 51. b) Lutz, R.E. J . Am. Chem. Soc. 1 9 2 6 , 48/ 2905. c) Lutz, R.E. Org. Syntheses C o l l . 1 9 2 3 , 3, 248. 76. Mosby, W.L. J . Am. Chem. Soc. 1 9 5 2 , 74, 2564. 77. a) Baker, B.R.; Schaub, R.E.; Joseph, J.P.; McEnvoy, F.J.; William, J.H. J . Org. Chem. 1 9 5 2 , 17, 149. b) Hart, H.; Oku, A. J . Org. Chem. 1 9 7 2 , 37, 4269. c) Schiner, C.S.; Noordik, J . ; Fisher, A.M.; Eckley, D.M.; Bodenhamer, J.; Haltiwanger, R.C Acta Crvst. 1 9 8 4 , Ç40, 540. d) Kamada, T.; Wasada, N. Synthesis 1 9 9 0 , 967. 78. S i l v e r s t e i n , R.M.; Bassler, G.C; M o r r i l l , T.C "Spectrometric I d e n t i f i c a t i o n of Organic Compounds", Vol. 4, Wiley, New York, 1 9 8 1 , 220. 79. See Bondi, A. J . Phvs. Chem. 1 9 6 4 , 68, 441. for commonly accepted values. Non-bonded interatomic repulsion energies increases dramatically below the sum of van der Waals r a d i i of the p a r t i c i p a t i n g atoms. For examples see: L i i , J.H.; A l l i n g e r , N.L. J . Am. Chem. Soc. 1 9 8 9 , 111. 8576. and references c i t e d therein.  80. The n o m e n c l a t u r e o f t h e b e n z o s e m i b u l l v a l e n e s was d e d u c e d f r o m a n a l y s i s o f many s u b s t i t u t e d a n a l o g s d e s c r i b e d i n C h e m i c a l A b s t r a c t s i n c o n j u n c t i o n w i t h : G o d l y , E.W. "Naming O r g a n i c Compounds", E l l i s H o r w o o d L t d . , L o n d o n , 1989, p 6 7 . 81. N i c o l a i d e s ,  D.N.; L i t i n a s ,  K.E. C h i m i k a C h r o n i k a 1982, 1 1 ,  137.  82. ORTEP i s a n a c r o n y m f o r Oak R i d g e T h e r m a l E l i p s o i d P r o g r a m (1964), r e v i s e d i n 1976. T h i s i s a c r y s t a l l o g r a p h i c d r a w i n g p r o g r a m s h o w i n g v i b r a t i o n a l motions. 83. Bender,  CO.; Brooks,  D.W.  C a n . J . Chem. 1975, 5 3 ,  1684.  84. A f t e r t h i r t e e n r u n s , t h e r a t i o o f 29a/29a+29b was e s t a b l i s h e d t o b e 0.675 ( s t d . d e v . = 0 . 0 5 ) . The e r r o r i n t h i s r a t i o was t a k e n t o b e 0.1 ( 2 X s t d . d e v . ) f o r 9 5 % c e r t a i n t y . T h i s e r r o r o f a p p r o x . 1 5 % p r o v i d e s an i d e a o f t h e p r e c i s i o n i n subsequent r a t i o d e t e r m i n a t i o n s . 85. M u r o v , S.L. "Handbook o f P h o t o c h e m i s t r y " , M a r c e l D e k k e r , 1973, p 3.  New Y o r k ,  86.  T u r r o , N . J . "Modern M o l e c u l a r P h o t o c h e m i s t r y " , M e n l o P a r k , 1978, p p . 4 8 5 - 4 8 7 .  Benjamin/Cummings,  87.  Bender,  88.  C h a r a c t e r i s t i c s i g n a l p a t t e r n s were p r o v i d e d t h r o u g h p e r s o n a l c o r r e s p o n d e n c e w i t h C O . Bender, U n i v . L e t h b r i d g e , A l t a . Canada.  89.  Trotter, J . Acta Cryst.  90.  a ) S c h e f f e r , J.R. A c c . Chem. R e s . 1980, 1 3 , 2 8 3 . b ) S c h e f f e r , J . R . ; W o s t r a d o w s k i , R.A. J . O r g . Chem. 1972, 3 7 , 4 3 1 7 .  C O . ; D o l m a n , D. ; T u , N. J . O r g . Chem. 1991, 5 6 ,  1989, Ç 4 5 ,  5015.  1250.  91. a ) P a u l , I . e . ; C u r t i n , D.Y. A c c . Chem. R e s . 1973, 6, 2 1 7 . b) H a s t i n g s , D.L.; Weedon, A . C J . Am. Chem. S o c . 1991, 1 1 3 , 8 5 2 5 . c ) C r i s t o l , S . J . ; H a g e r , J.W. J . O r g . Chem. 1983, 4 8 , 2 0 0 5 . 92.  S i l v e r s t e i n , R.M. ; B a s s l e r , G . C ; M o r r i l l , T.C. " S p e c t r o m e t r i c I d e n t i f i c a t i o n o f O r g a n i c Compounds", V o l . 4, W i l e y , New Y o r k , 1981, p 120.  93. J e n s e n ,  F.R.; C o l e m a n , W.E.;  B e r l i n , A.J. Tetrahedron Lett.  94. M e i e r , R.; L o t t e r , H.G. Chem. B e r . 1957, 9 0 , 95.  1962, 15.  222.  The f o l l o w i n g b o n d d i s t a n c e s w e r e d e t e r m i n e d b y J . T r o t t e r a n d h i s c r y s t a l l o g r a p h y g r o u p i n s u p p o r t o f t h i s t h e s i s . The n u m b e r s i n parentheses are standard deviations o f the l e a s t s i g n i f i c a n t f i g u r e .  96.  Flemming, I . " F r o n t i e r O r b i t a l s and O r g a n i c Chemical R e a c t i o n s " , W i l e y , New Y o r k , 1980, p 2 0 1 .  97.  G r i f f i n , G.W.; Padwa, A. " P h o t o c h e m i s t r y o f H e t e r o c y c l i c e d . B u c h a r t , 0.; W i l e y , New Y o r k , 1976, p 4 1 .  Compounds",  98. a) Dauben, W.G.; Shaffer, G.W.; Deving, E.J. J . Am. Chem. Soc. 1 9 7 0 , 92, 6273. b) Hess, L.D.; Jacobson, J.L.; Schaffner, K.; P i t t s , J.N. J . Am. Chem. Soc. 1 9 6 4 , 89/ 3684. 99. Garcia-Garibay, M.; Scheffer, J.R.; Watson, D.G. J . Org. Chem. 1 9 9 2 , 57, 241. 100. Lowry, T.H. and Richardson, K.S. "Mechanism and Theory i n Organic Chemistry", 3rd ed.. Harper & Row Pub., New York, 1 9 8 7 , p 767. 101. For examples see: a) Reddy, G.D.; Jayasree, B. ; Ramamurthy, V. J . Org. Chem. 1 9 8 7 , 52., 3107. b) Casal, H.L.; de Mayo, P.; Miranda, J.F.; Scaiano, J.C. J . Am. Chem. Soc. 1 9 8 3 , 105, 5155. 102. Rao, B.N.; Syamala, M.S.; Turro, N.J.; Ramamurthy, V. J . Org. Chem. 1987, 52, 5517. 103. Several values f o r acetylene have been reported: a) Ô = 1.80; Clerc, T.; Pretsch, E.; S e i b l , J . ; Simon, W. "Tables of Spectral Data for Structural Determination of Organic Compounds", 2nd. ed., Springer-Verlag, B e r l i n , 1 9 8 5 , p H225. b) Ô = 2.3; Cooper, J.W. "Spectroscopic Techniques f o r Organic Chemists", Wiley, New York, 1 9 8 0 , p 64. c) Ô = 2.7; Lambert, J . ; Shurvell, H.F.; Lightner, D.; Cooks, R.G "Introduction to Organic Spectroscopy", MacMillan, New York, 1987, p 45. 104. Murray, R.K., J r . ; Hart, H. Tetrahedron L e t t . 1 9 6 8 , 4965. 105. a) Weisman, G.R. i n "Asymmetric Synthesis", Morrison, J.D. ed.. Vol. 1, Academic Press, New York, 1 9 8 3 , p. 166. b) Kasler, F. "Quantitative Analysis by NMR Spectroscopy", Academic Press, London, 1 9 7 6 , p 78. 106. S i l v e r s t e i n , R.M.; Bassler, G.C; M o r r i l l , T.C. "Spectrometric I d e n t i f i c a t i o n of Organic Compounds", V o l . 4, Wiley, New York, 1 9 8 1 , p 122. 107. a) Garcia-Garibay, M.; Scheffer, J.R.; Trotter, J . ; Wireko, F.C Acta. Crvst. 1 9 9 0 , B46, p 79. b) Garcia-Garibay, M.; Scheffer, J.R.; Trotter, J . ; Wireko, F . C Tetrahedron. L e t t . 1 9 8 8 , 29, 2041. 108. a) Bernstein, J . ; Cohen, M.D.; Leiserowitz, L. i n "The Chemistry of the Quinoid Compounds", Fatal, S., Ed.; Wiley: New York, 1 9 7 4 ; Ch. 2. b) Taylor, R.; Kennard, O. Acc. Chem. Res. 1 9 8 4 , 17, 320. c) Sarma, J.A.R.P.; Desiraju, G.R. Acc. Chem. Res. 1 9 8 6 , 1 9 , 222. 109. Vander-Donckt, E.; Vogels, C. Spectrochim. Acta 1 9 7 1 , 27A, 2157.  110. a) Pokkukuri, P.R.; Scheffer, J.R.; Trotter, J . J . Am. Chem. Soc. 1 9 9 0 , 112, 3676. b) Asokan, C.V.; Kumar, S.A.; Das, S.; Rath, N.P.; George, M.V. J. Org. Chem. 1 9 9 1 , 56, 5890. c) Chen, J . ; Pokkulurl, P.R.; Scheffer, J.R.; Trotter, J . J . Photochem. Photobiol. A; Chem. 1 9 9 1 , 21. 111. a) Bender, CO.; Dolman, D.; Gaetanne, K.M. Can. J . Chem. 1 9 8 8 , 66, 1656. b) Bender, CO.; Bengston, D.L.; Dolman, D.; O'Shea, S.F. Can. J . Chem. 1 9 8 5 , 64/ 237. 112. a) Doctoral Thesis of Pokkulurl, P.R., University of B r i t i s h Columbia, 1990, p 70. b) Gudmundsdottir, A.D.; Scheffer, J.R. Photochemistry and Photobiology 1 9 9 0 , 54/ 535. 113. A f a i r i n d i c a t i o n of r e l a t i v e electron donor capacities can be determined from the i o n i z a t i o n potentials of the functional groups. These are c i t e d i n Weast, R.C ed. "Handbook of Chemistry and Physics", 48th ed., Chemical Rubber Co., Cleveland, 1 9 6 8 , p E-69. 114. Lowry, T.H. and Richardson, K.S. "Mechanism and Theory i n Organic Chemistry", 3rd ed.. Harper & Row Pub., New York, 1 9 8 7 , p 229. 115. Birks, J.B. "Photophysics of Aromatic Molecules", Wiley, New York, 1970, p 403. 116. a) De Schryver, F. Adv. Photochem. 1 9 7 7 , 10, 359. b) Weller, A. Pure A P P I . Chem. 1 9 6 8 , 16, 115. 117. Kuchitsu, Fukuuyama, Morino J . Mol. Struct. 1 9 6 8 , 1, 463. 118. De Mayo, P., ed. "Rearrangements i n Ground and Excited States", Vol. 3, Academic Press, New York, 1 9 8 0 , pp. 221-226. 119. The molecular minimization program i s : PCMODEL, version 88.00, by Serena Software, 1 9 8 8 . 120. Bender, CO.; Bengston, D.L.; Dolman, D.; Herle, C.E.L.; O'Shea, S.F. Can. J . Chem. 1 9 8 2 , 60, 1942. and references c i t e d therein. 121. S t i l l , W.C; Kahn, M; Mitra, A. J . Org. Chem. 1 9 7 8 , 43, 2923. 122. Perrin, D.D.; Armarego, W.L.F.; Perrin, D.R. " P u r i f i c a t i o n of Laboratory Chemicals", 2nd ed., Permagon Press, Oxford, 1 9 8 0 . 123. Murov, S.L. "Handbook of Photochemistry", Marcel Dekker, New York, 1973, p 131. 124. Wagner, P.J.; Kochevar, I.; Kempainen, A.E. J . Am. Chem. Soc. 1 9 7 2 , 94, 7489.  125. Wagner, P.J. i n "Creation and Detection of the Excited State", Lamola, A.A. ed.. Marcel Dekker, New York, 1 9 7 1 .  

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