Open Collections

UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

Preparation of b-trialkylstannyl-a, b-unsaturated carbonyl compounds and their conversion to vinyllithium… Morton, Howard Eric 1981

Your browser doesn't seem to have a PDF viewer, please download the PDF to view this item.

Item Metadata

Download

Media
831-UBC_1981_A1 M67.pdf [ 8.37MB ]
Metadata
JSON: 831-1.0060744.json
JSON-LD: 831-1.0060744-ld.json
RDF/XML (Pretty): 831-1.0060744-rdf.xml
RDF/JSON: 831-1.0060744-rdf.json
Turtle: 831-1.0060744-turtle.txt
N-Triples: 831-1.0060744-rdf-ntriples.txt
Original Record: 831-1.0060744-source.json
Full Text
831-1.0060744-fulltext.txt
Citation
831-1.0060744.ris

Full Text

PREPARATION OF B-TRIALKYLSTANNYL-a , $ -UNSATURATED CARBONYL COMPOUNDS AND THEIR CONVERSION TO VINYLLITHIUM REAGENTS by HOWARD ERIC MORTON .Sc., U n i v e r s i t y o f B r i t i s h C o l u m b i a , 1976 THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY i n THE FACULTY OF GRADUATE STUDIES (Department o f C h e m i s t r y ) We a c c e p t t h i s t h e s i s as c o n f o r m i n g t o t he r e q u i r e d s t a n d a r d THE UNIVERSITY OF BRITISH COLUMBIA F e b r u a r y 1981 (c) Howard E r i c Morton In presenting t h i s thesis i n p a r t i a l f u l f i l m e n t of the requirements fo r an advanced degree at the University of B r i t i s h Columbia, I agree that the Library s h a l l make i t f r e e l y a v a i l a b l e for reference and study. I further agree that permission for extensive copying of t h i s thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. It i s understood that copying or p u b l i c a t i o n of t h i s thesis for f i n a n c i a l gain s h a l l not be allowed without my written permission. The University of B r i t i s h Columbia 2075 Wesbrook Place Vancouver, Canada V6T 1W5 Department of DE-6 (2/79) ABSTRACT The p r e p a r a t i o n and s y n t h e t i c u t i l i t y of v a r i o u s g - t r i a l k y l s t a n n y l - a , g - u n s a t u r a t e d c a r b o n y l compounds i s d e s c r i b e d . In t h i s c o n n e c t i o n , treatment of t e t r a h y d r o f u r a n s o l u t i o n s o f Me^SnLi and n-Bu^SnLi with one e q u i v a l e n t of PhSCu l e d to the i n s i t u f ormation of PhS(Me-^Sn)CuLi 72 and PhS (n-Bu^Sn)CuLi 7_3, r e s p e c t i v e l y . The l a t t e r reagents r e a d i l y t r a n s f e r r e d , i n a conjugate sense, the t r i a l k y l -s t a n n y l group to a,g-unsaturated c a r b o n y l systems. In p a r t i c u l a r , these t r i a l k y l s t a n n y l c u p r a t e reagents e f f i c i e n t l y transformed g-iodo enones 4_ i n t o g - t r i a l k y l s t a n n y l - a , g-u n s a t u r a t e d ketones 1^, a new c l a s s of o r g a n o t i n d e r i v a t i v e s . L i k e w i s e , treatment of the g-iodo enones 4_ with Me^SnCu • L i B r • SMe2 9_4, prepared by the r e a c t i o n of Me^SnLi wit h one e q u i v a l e n t of Me2S*CuBr, gave the corresponding 6 - t r i m e t h y l s t a n n y l enones i n good y i e l d . Two of these g - t r i a l k y l s t a n n y l enones,.3-trimetehyl-s t a n n y l - 2 - c y c l o h e x e n - l - o n e 7_0 and 3 - t r i - n - b u t y l s t a n n y l - 2 -c y clohexen-l-one, 74_ were transformed i n t o the v i n y l i t h i u m reagent 111. S e q u e n t i a l treatment of the enones 7_0 and 7_4 with l i t h i u m d i i s o p r o p y l a m i d e and t e r t - b u t y l d i m e t h y l s i l y l c h l o r i d e i n the presence of hexamethylphosphoramide gave the enol s i l y l e t h e r s 110 and 108, r e s p e c t i v e l y . T r a n s m e t a l a t i o n o f the compounds 110 and 108 was a c c o m p l i s h e d by t r e a t m e n t o f t h e s e s u b s t a n c e s w i t h 1.1 e q u i v a l e n t o f an a l k y l l i t h i u m r e a g e n t . R e a c t i o n o f t h e r e s u l t a n t v i n y l l i t h i u m r e a g e n t 111 w i t h e l e c t r o p h i l i c r e a g e n t s proceeded smoothly t o a f f o r d t h e c o r r e s p o n d i n g s u b s t i t u t e d 1 , 3 - c y c l o h e x a d i e n e s i n good y i e l d . The r e a c t i o n o f PhS(Me^Sn)CuLi 72_ w i t h v a r i o u s a, 6-a c e t y l e n i c e s t e r s i s a l s o d e s c r i b e d . The c o u r s e o f the r e a c t i o n c o u l d be c o n t r o l l e d e x p e r i m e n t a l l y so as t o produce, h i g h l y s t e r e o s e l e c t i v e l y , e i t h e r t h e (E) - o r t h e ( Z ) - & -t r i m e t h y l s t a n n y l - c t , g - u n s a t u r a t e d e s t e r s . Treatment (THF, -78°C) o f PhS ( M e 3 S n ) C u L i 7_2 w i t h a, 6 - a c e t y l e n i c e s t e r s i n the p r e s e n c e o f a p r o t o n s o u r c e ( e . g . , MeOH) gave the c o r r e s p o n d i n g ( E ) - S - t r i m e t h y l s t a n n y l - a , g - u n s a t u r a t e d e s t e r s i n good y i e l d . R e a c t i o n o f 7_2 w i t h a , g - a c e t y l e n i c e s t e r s a t s l i g h t l y h i g h e r t e m p e r a t u r e s (-48°C) i n the absence o f a p r o t o n s o u r c e r e s u l t e d i n the f o r m a t i o n o f the c o r r e s p o n d i n g ( Z ) - i s o m e r s . R e a c t i o n o f e t h y l ( Z ) - 3 - t o s y l o x y a c r y l a t e 180 w i t h Me 3SnCu*LiBr-SMe 2 94 and n-Bu 3SnCu•LiBr*SMe 2 181 gave the c o r r e s p o n d i n g ( Z ) - B - t r i a l k y l s t a n n y l a c r y l a t e s . F i n a l l y , two o f the B - t r i m e t h y l s t a n n y l e s t e r s , e t h y l ( E ) - 3 - t r i m e t h y 1 s t a n n y 1 - 2 - b u t e n o a t e 163 and e t h y l (Z)-3-t r i m e t h y l s t a n n y l - 2 - b u t e n o a t e 166, were c o n v e r t e d i n t o t he g e o m e t r i c a l l y i s o m e r i c t r i m e t h y l s t a n n y l d i e n e s 184 and 185, - I V respectively. Both of these substances underwent rapid and complete transmetalation when treated with 1.2 equivalents of methyllithium i n tetrahydrofuran. The resultant 4-lithio-l,3-pentadienes (186 , 187) reacted smoothly with a variety of electrophiles to produce the corresponding substituted dienes (192 and 193). SnRc 70 SnMeg SnBu n 3 74 0SiMe2Bu t 0SiMe2Bu t 0SiMe2Bu t SnBu n 3 108 SnMe3 110 i n Me 3Sn Me3Sn Li a 163 184 186 192 166 185 187 193 - v -TABLE OF CONTENTS Page TITLE PAGE i ABSTRACT i i TABLE OF CONTENTS V LIST OF TABLES v i i ACKNOWLEDGEMENTS v i i i INTRODUCTION 1 I General 1 II The Problem 2 I I I S e l e c t e d examples of Previo u s 4 Reports Concerning B - A c y l v i n y l Anion E q u i v a l e n t s DISCUSSION 13 I Attempted P r e p a r a t i o n o f 13 3 - t e r t - b u t y l d i m e t h y l s i l o x y - l , 3 -c yclohexadiene 64_ I I P r e p a r a t i o n o f 3 - T r i a l k y l s t a n n y l - 18 a , B-unsaturated Ketones I I I P r e p a r a t i o n of l - L i t h i o - 3 - 38 t e r t - b u t y l d i m e t h y l s i l o x y - 1 , 3 -cyclohexadiene 111 and i t s r e a c t i o n w i t h E l e c t r o p h i l e s IV P r e p a r a t i o n o f 0 - T r i a l k y l s t a n n y l 53 Ketones and E s t e r s - v i -Page V Preparation of 3-Trialkylstannyl- 67 a,g-unsaturated Esters VI Preparation of (E)- and (Z)-4- 8 9 Lithio-1,3-pentadienes and Their Reactions with Electrophiles EXPERIMENTAL 98 BIBLIOGRAPHY 204 - v n -LIST OF TABLES Reaction of PhS (Me3Sn) CuLi 7_2 and PhS(n-Bu 3Sn)CuLi 73 with 3-Iodo Enones Reaction of Me 3SnCu•LiBr•SMe 2 9£ with 3-Iodo Enones The UV Absorption Maxima ) of some max B-Trialkylstannyl Enones and Their Parent B-Unsubstituted Enones Reaction of l - L i t h i o - 3 - t e r t -butyldimethylsiloxy-1,3-cyclohexadiene 111 with Electrophiles Reaction of Various T r i a l k y l s t a n n y l Reagents with a,3-Unsaturated Ketones and Esters Reaction of Me^SnLi and PhS(Me^Sn)CuLi 72 with Methyl V i n y l Ketone and Ethyl Acrylate Preparation of B-Trimethylstannyl-a,3 unsaturated Esters The UV Absorption Maxima ) of some ^ max a,B-Unsaturated Esters and B-Trialkylstannyl B-unsaturated Esters Reaction of 4-Lithio-l,3-pentadienes 184 and 185 with Electrophiles - v i i i -AC KNOWLE DGEMENT S I would l i k e to express my sincere thanks to Dr. Edward Piers for his excellent guidance throughout the course of this work. I t has been a very rewarding experience to work under his d i r e c t i o n . I would also l i k e to thank the many members of Dr. Piers' research group, past and present, for their understanding f r i e n d -ships and many helpful discussions. Special thanks must be extended to Mrs. Annette Hiom for her prompt and e f f i c i e n t typing of thi s manuscript. I also wish to thank Mr. Ian Suckling, Mr. Michael Chong, and Mr. Max Burmeister for proof reading the thesis. The f i n a n c i a l support from the Natural Sciences and Engineering Research Council Canada (1976-1980) i s g r a t e f u l l y acknowledged. i x The s t r u g g l e a l o n e p l e a s e s us, n o t the v i c t o r y . PASCAL INTRODUCTION I G e n e r a l a , 6 - U n s a t u r a t e d c a r b o n y l compounds p l a y an i m p o r t a n t r o l e i n modern o r g a n i c c h e m i s t r y . These compounds owe t h e i r s y n t h e t i c u t i l i t y m a i n l y t o the p r e s e n c e of the c a r b o n -oxygen d o u b l e bond. The c a r b o n y l oxygen atom n o t o n l y c o n f e r s e l e c t r o p h i l i c r e a c t i v i t y upon the c a r b o n y l c a r b o n atom, but a l s o i m p a r t s n u c l e o p h i l i c and e l e c t r o p h i l i c c h a r a c t e r upon the a-carbon and 3-carbon atoms, r e s p e c t i v e l y . As a r e s u l t , the 3-carbon atom of the a , 3 - u n s a t u r a t e d system i s a r e c e p t o r f o r n u c l e o p h i l e s and f r e e r a d i c a l s , b u t not f o r e l e c t r o p h i l e s . The r e v e r s e mode of r e a c t i v i t y can be a c h i e v e d v i a r e a c t -i v i t y umpolung.''" T h i s i n v o l v e s c o n v e r s i o n o f the normal ( e l e c t r o p h i l i c ) c h a r a c t e r o f t h e 3-carbon atom i n t o n u c l e o -p h i l i c r e a c t i v i t y (eq. 1). I n p r a c t i c e t h i s can be r e a l i z e d t h r o u g h t h e i n t e r m e d i a c y o f masked a , 3 - u n s a t u r a t e d c a r b o n y l compounds, which behave s y n t h e t i c a l l y as e q u i v a l e n t s o f the 3 - a c y l v i n y l a n i o n s 2_. T h i s type o f methodology has g r e a t l y extended the s y n t h e s i s and s y n t h e t i c u t i l i t y o f a , S - u n s a t u r a t e d c a r b o n y l compounds. 1 - 2 -II The Problem Previous work i n our laboratory has demonstrated that 2 g-bromo- 3_ and g-iodo-a,g-unsaturated ketones 4_ serve as 3 4 excellent synthetic equivalents of g-acylvinyl cations 5. ' For example, reaction of these g-halo enones with a l k y l X x 5 © cuprate reagents produced the corresponding 3-alkyl-a, g-unsaturated ketones 6_ i n excellent y i e l d (eq. 2) . X 2 X=Br 4 X-I RRCuLi -> y ^ R (2) Certain of these g-substituted enones 6_ have proven to be very useful for the d i r e c t formulation of functionalized f i v e ^ ' ^ and seven^ C ' e ' f ' ^  membered rin g systems. The objective of the work described i n t h i s thesis was to investigate the p o s s i b i l i t y of extending this - 3 -methodology to the use of g-iodo enones 4 as potential precursors of synthetic equivalents of the g-acylvinyl anions 2_. Presumably, th i s would involve protection of the carbonyl group of followed by lithium-iodine exchange (e.g., alkyllithium) of the protected species 7, to produce 8_ (the synthetic equivalent of 2, eq. 3). Treatment of 8 with e l e c t r o p h i l i c reagents ("E+") would afford, after removal of the protecting group from the i n i t i a l l y formed products 9_, the 6-substituted enones 10. 4 7 8 9 10 P=protecting — group A l t e r n a t i v e l y , i t may be possible to convert the g-iodo enone 4_ into some other functionalized enone, such as the g-t r i a l k y l s t a n n y l d e r i v a t i v e 11_, which could then be transformed into 8_. For example, protection of the carbonyl group of 11, g followed by transmetalation (e.g., alkyllithium) of the - 4 -protected species 12_ would produce the desired anion 8_ (eq. 4) . 4 11 12 8 P=protecting group Cl e a r l y , these proposed methodologies (eq. 3 and 4), i f successful, would complement that involving treatment of 4_ with nucleophilic reagents. I l l Selected Examples of Previous Reports Concerning  B-Acylvinyl Anion Equivalents During the past several years there have been a number of reports i n the chemical l i t e r a t u r e concerning the use and development of synthetic equivalents of B-acylvinyl anions 2. - 5 -A b r i e f description of several of these i s i n order.* Recently Kondo et al_. developed a novel method for the conversion of a, g-unsaturated carbonyl compounds into g-acylvinyl anion equivalents v i a Y~°xosulfone acetals 8 9 and ketals 14^ . ' Reaction of the sulfones 1_4 (easily prepared i n two or three steps from the corresponding a , g-unsaturated carbonyl compounds 13_) with n -butyllithium resulted i n the formation of the a-carbanion 15 (eq. 5). (5) 16 17 Alky l a t i o n of 1_5 (the synthetic equivalent of 2) with various e l e c t r o p h i l i c reagents ("E+") proceeded smoothly. Acid * This b r i e f account i s not meant to be exhaustive, but i s given only to provide the reader with some background i n this area. The examples were chosen for their generality and/or for their close r e l a t i o n s h i p to the work discussed in t h i s thesis. For other reports of g-acylvinyl anion equivalents see reference 7. - 6 -hydrolysis of the sulfones 16_ thus formed, followed by treatment of the resultant product with base afforded the substituted a,g-unsaturated aldehydes and ketones. g-Nitro esters and ketals have been shown to serve as useful reagents for the synthesis of a,g-unsaturated carbonyl compounds.-'-0 These n i t r o compounds re a d i l y added to aldehydes and reactive enones under mildly basic conditions. For example, treatment of a mixture of heptanal and ethyl g-nitropropionate 18_ with diisopropylamine produced the intermediate 19_ (eq. 6) . Prolonged treatment (i-pr)2NH N02 C 6H 1 3CHO + o 2 N ^ v ^ C 0 2 E t > C 6 H 1 3 Y ^ ^ C 0 2 E t OH 1 8 ± i ' ~ (6) of 19 with base resulted i n the elimination of nitrous acid to afford the y~hydroxy acrylate 2_0. In similar fashion, reaction of the g-nitro ketal 2_1 with enones i n the presence of base afforded the substituted g-nitro ketal 22 (eq. 7) . Acid hydrolysis of 22_ followed by treatment - 7 -o f the r e s u l t a n t g - n i t r o ketone 2_3 w i t h base produced w i t h e - k e t o enone 24 i n good y i e l d . (7) 23 24 Seebach e t a_l. have u t i l i z e d an i n t r a m o l e c u l a r analogue o f the above methodology f o r the s y n t h e s i s o f c y c l o p e n t e n o n e s . 1 R e a c t i o n of an amine f r e e s o l u t i o n o f the l i t h i u m e n o l a t e 2_5 w i t h g - n i t r o p r o p i o n y l c h l o r i d e a t low t e m p e r a t u r e f u r n i s h e d the d i k e t o n e 2_6_ (eq. 8) . C y c l i z a t i o n o f 2_6 w i t h base, f o l l o w e d by e l i m i n a t i o n o f n i t r o u s a c i d from the r e s u l t a n t i n t e r m e d i a t e 27 a f f o r d e d the c y c l o p e n t e n o n e 2_8_. The enone 28_ r e a r r a n g e d c o m p l e t e l y t o the isomer 2_9_ when the r e a c t i o n was a l l o w e d t o - 8 -run over an extended period of time. A somewhat similar methodology for the 3-alkylation of 12 a,g-unsaturated ketones was developed by Larcheveque e t . a l . These workers u t i l i z e d the reversible conjugate addition of cyanide ion for the a c t i v a t i o n of the B-carbon atom (eq. 9). Treatment of the keto n i t r i l e 3_0 with two equivalents of lithium diisopropylamide (LDA) afforded the dianion 31^  (the synthetic equivalent of 2) . Reaction of 3_1 with one equiv-alent of an a l k y l a t i n g reagent i n the presence of hexamethyl-- 9 -Q Q OLi -> LDA > *t y ^ C N 30 V 31 -Li = CN X HMPA OLi RX Y ^ V CN 32 (9) phosphoramide (HMPA) resulted i n monoalkylation alpha to the n i t r i l e f u n c t i o n a l i t y . Warming of the enolate 32^  thus obtained, effected g-elimination of cyanide ion to afford the substituted enone 3_3. However, i n some cases the keto n i t r i l e 3_6 was formed, apparently derived from the intermediate 3_5, which i n turn was formed by base extraction of an a 1 -proton from 3_4 (eq. 10). Treatment of 36 with base afforded a mixture of H DRX ^ 'Ll 2)H20 CN R CN Base ^ (10) - 10 -the a,g- and g,Y-unsaturated ketones 37. Recently Fuchs et a l . developed a novel method for the 13 preparation of a,g-unsaturated ketones (eq. 11). Reaction of the g-epoxy sulfone 3_8 with one equivalent of an a l k y l l i t h i u m reagent produced the a,g-unsaturated sulfone intermediate 39, which re a d i l y underwent conjugate addition of a second equivalent of an a l k y l l i t h i u m reagent to afford the dianion 40. P a r t i c i p a t i o n of the alkoxide oxygen was probably Q OLi R L L > \' ^ ^ S 0 2 P h 38 RLi > y^so 2Ph 39 1) RX 2) NH4Cl' OH OLi R Li R S0 2 Ph 41 40 1) H 2 Cr 20 7 v > \ 2) Base 42 S0 2 Ph (ii) 14 responsible for the p r e v a i l i n g stereochemistry. Treatment of 40 with a l k y l a t i n g reagents afforded the corresponding yhydroxy sulfones 4_1. Oxidation of 4_1 followed by elimination of the g-sulfonyl moiety generated the enones 4_2 i n good o v e r a l l y i e l d . For example, the enone 44 was produced i n 89% o v e r a l l y i e l d (eq.12) - 11 -O UPhLi V 2) Mel 3 )H 2 Cr 20 7 B0 2 P h 4)Base > 0 Me Ph (12) 43 44 Thus, the 3-epoxy s u l f o n e s 3_8 were used as p r e c u r s o r s t o t h e s y n t h e t i c e q u i v a l e n t o f the d o u b l y charged s p e c i e s 45. A n o t h e r approach t o 3 - a c y l v i n y l a n i o n e q u i v a l e n t s i s t h e m e t a l a t i o n o f c e r t a i n B - h a l o - a , B - u n s a t u r a t e d c a r b o x y l i c a c i d s and t e r t i a r y amides. For example, l i t h i u m - b r o m i n e exchange 15 16 o f the g-bromo a c i d 4_6 and amide 49_ w i t h two e q u i v a l e n t s o f n - b u t y l l i t h i u m and t e r t - b u t y l l i t h i u m r e s p e c t i v e l y , f o l l o w e d by t r e a t m e n t o f the r e s u l t a n t v i n y l l i t h i u m r e a g e n t s 4_7 and 5_0 w i t h c a r b o n y l e l e c t r o p h i l e s a f f o r d e d the c o r r e s p o n d i n g y - l a c t o n e s 48_ and 5_1 (eq. 13 and 1 4 ) . 0 45 - 12 -- 13 -DISCUSSION I Attempted Preparation of 3-tert-Butyldimethylsiloxy-1,3-cyclohexadiene Although a variety of methods have been developed for the preparation of 6-acylvinyl anion equivalents, few have involved the intermediacy of 3-iodo enones 4_. Recently however, the conversion of these l a t t e r compounds into the mixed vinylcuprate reagents 5_2, a process quite s i m i l a r to the one which we wished 17-20 to accomplish, has been reported. These vinylcuprate t± 5_2 P=protecting group reagents 5_2 reacted smoothly with a variety of e l e c t r o p h i l i c reagents. For example, reduction of the c y c l i c g-iodo enones 53 with sodium borohydride, followed by protection of the 21 r e s u l t i n g alcohols 5_4 using the procedure developed by Corey 18 19 gave the s i l y l ethers 5_5 (eq. 15). ' Lithium-iodine exchange of 5_5 was accomplished by treatment of the l a t t e r substances with two equivalents of t e r t - b u t y l l i t h i u m . Treat-ment of the resultant v i n y l l i t h i u m reagents 5_6_ with 3-methoxy-3-methyl-l-butynylcopper resulted i n the formation of the mixed - 14 -59 60 cuprate reagents 5_7_. Reaction of 57_ with the benzoate 58 followed by treatment of the resultant mixtures with tetra-n-butylammonium fl u o r i d e gave the alcohols 5_9 i n excellent 18 19 y i e l d . ' The conversion of 5_9_ into the corresponding enones 60^  was not attempted. However, these transformations should pose no problem.* Although a variety of other carbonyl protecting groups could be envisaged, we f e l t that an enol s i l y l ether function-a l i t y (cf. 6^ 1) might be a good choice. This functional group, i n addition to being amenable to introduction and removal under mild reaction conditions, i s i t s e l f s y n t h e t i c a l l y 22 very v e r s a t i l e . Thus, i t was hoped that lithium-iodine exchange of the enol s i l y l ether 6_1 would r e s u l t i n the formation of the v i n y l l i t h i u m reagent 6_2 (the synthetic equivalent of 2). The l a t t e r species could then be allowed to react with a variety of e l e c t r o p h i l i c reagents. * For a number of related examples a c y c l i c 3-iodo enones as precursors equivalents, see reference 20. involving the use of to 3-acylvinyl anion - 16 -2 However, attempted conversion of the 3-iodo enone 63 into the enol s i l y l ether derivative 6_4, under a variety of experimental conditions, f a i l e d to produce s y n t h e t i c a l l y useful y i e l d s of the desired product- For example, reaction of 6_3 with 1.1 equivalents of lithium diisopropylamide (LDA) in tetrahydrofuran at -78°C for 90 min, followed by treatment of the resultant enolate anion(s) with t e r t - b u t y l d i m e t h y l s i l y l chloride i n the presence of hexamethylphosphoramide (HMPA) afforded a yellow o i l in ^ 45% y i e l d (based on unrecovered 23 st a r t i n g material). Spectral analysis of t h i s material indicated that i t was composed of a mixture of the enol s i l y l ethers 6_4 and 6_5 along with 6_3 i n a r a t i o of 62:23:15, respectively (eq. 16).* The 1H nmr spectrum of t h i s material P. 0SiMe2But OSiM^Bu 1 63 2) t-BuMe2SiCI k-^M ~ ( 1 6 ) 63 64 exhibited a t r i p l e t (J=2Hz) at 66.30 and a multiplet at 64.92 which were attributed to the C-2 and C-4 o l e f i n i c protons, respectively, of the enol s i l y l ether 64.** There was also * Similar r e s u l t s were obtained when lithium 2,2,6,6-tetra-methylpiperidide was employed as base. ** The chemical s h i f t s are r e l a t i v e to C H C I 3 . These assignments were based on subsequent ^-U nmr analysis of the corresponding 1 - t r i a l k y l s t a n n y l derivatives of 64. - 17 -p r e s e n t i n the H nmr spectrum o f t h i s m i x t u r e a broad s i n g l e t a t 6 5.37 and a m u l t i p l e t a t 6 5.97. These were a t t r i b u t e d t o the C-2 and C-4 o l e f i n i c p r o t o n s o f the i s o m e r i c e n o l s i l y l e t h e r 6_5, r e s p e c t i v e l y . A l l a t t e m p t s t o s e p a r a t e the e n o l s i l y l e t h e r s 6_4 and 6_5_ were u n s u c c e s s f u l . F u r t h e r m o r e , t h i s m i x t u r e , even when s t o r e d under an atmosphere o f argon i n a f r e e z e r , would dar k e n and decompose f a i r l y r a p i d l y ( s e v e r a l I n v iew o f the o b s e r v a t i o n s summarized above, a n o t h e r means f o r p r o d u c i n g the 3 - a c y l v i n y l a n i o n e q u i v a l e n t 6_2 was sought. I n t h i s c o n n e c t i o n , the f o r m a t i o n o f v i n y l l i t h i u m r e a g e n t s by t r a n s m e t a l a t i o n o f t r i a l k y l v i n y l s t a n n a n e s i s a w e l l known p r o c e s s (eq. 1 7 ) . T h e r e f o r e , the ( p r o j e c t e d ) f o r m a t i o n o f the 3 - a c y l v i n y l a n i o n e q u i v a l e n t 6_2 v i a the t r i a l k y l s t a n n y l d e r i v a t i v e 6_6 became an a t t r a c t i v e p o s s i b i l i t y . P resumably, p u t t i n g t h i s i d e a i n t o p r a c t i c e would i n v o l v e (a) the c o n v e r s i o n o f the 3-iodo enones 4_ i n t o the c o r r e s p o n d i n g days) . 3 (17) - 18 -g-trialkylstannyl - a,g-unsaturated ketones 11_, (b) protection of the carbonyl group of L l as the enol s i l y l ether 6_6, and (c) transmetalation of the protected species 6_6 to produce 62.. II Preparation of g-Trialkylstannyl-ct, g-unsaturated Ketones Recently the addition of a l k y l l i t h i u m reagents to t e t r a -hydrofuran (THF) solutions of hexaalkyldistannanes has provided an e f f i c i e n t route to the corresponding t r i a l k y l s t a n n y l l i t h i u m 24 reagents (eq. 18). The l a t t e r reagents can also be prepared by the t i t r a t i o n of a cold (-70°C) solution of lithium i n R3Sn-SnR3 RLi -> R3Snl_i + R^ Sn (18) - 19 -l i q u i d ammonia w i t h a t e t r a h y d r o f u r a n s o l u t i o n o f the 24 a p p r o p r i a t e h e x a a l k y l d i s t a n n a n e . However, r e g a r d l e s s o f t h e method of p r e p a r a t i o n , t e t r a h y d r o f u r a n o r t e t r a h y d r o f u r a n -ammonia s o l u t i o n s o f t r i a l k y l s t a n n y l l i t h i u m r e a g e n t s (R=Me, n-Bu) r e a d i l y undergo M i c h a e l - t y p e a d d i t i o n s t o a , p - u n s a t u r a t e d k e t o n e s and e s t e r s t o a f f o r d the c o r r e s p o n d i n g g - t r i a l k y l s t a n n y l 24 25 c a r b o n y l compounds 6J7 i n e x c e l l e n t y i e l d (eq. 19) . ' F o r example, 2 - c y c l o h e x e n - l - o n e 68_ r e a c t e d c l e a n l y w i t h a t e t r a h y d r o f u r a n s o l u t i o n o f t r i m e t h y l s t a n n y l l i t h i u m (-78°C, 5 min) t o g i v e the g - t r i m e t h y l s t a n n y l ketone 69_ i n 96% y i e l d (eq. 2 0 ) . None o f the c o r r e s p o n d i n g 1,2 adduct c o u l d be d e t e c t e d . - 20 -E a r l i e r work i n our l a b o r a t o r y had found t h a t the B - i o d o enones £ s e r v e as e x c e l l e n t s y n t h e t i c e q u i v a l e n t s o f B - a c y l v i n y l c a t i o n s 5 (summarized e a r l i e r i n t h i s t h e s i s ) . I t was t h e r e f o r e o f i n t e r e s t t o i n v e s t i g a t e whether o r n o t t h e s e compounds c o u l d be c o n v e r t e d i n t o the c o r r e s p o n d i n g 3 - t r i a l k y l s t a n n y l d e r i v a t i v e s 11 by r e a c t i o n w i t h t r i a l k y l s t a n n y l l i t h i u m r e a g e n t s . o 0 A 5 © A v ^ S n R 3 i i T reatment o f 3 - i o d o - 2 - c y c l o h e x e n - l - o n e 63^ w i t h one e q u i v a l e n t o f t r i m e t h y l s t a n n y l l i t h i u m i n t e t r a h y d r o f u r a n a t -78°C f o r l h a f f o r d e d a y e l l o w o i l . A g l c a n a l y s i s o f t h i s m a t e r i a l showed t h a t i t was composed o f t h r e e major components. Other minor u n i d e n t i f i e d p r o d u c t s (^11%) were a l s o p r e s e n t . The major components were shown t o be the enone 70 (^32%), the ketone 71 (^15%) , and t h e s t a r t i n g m a t e r i a l 63_ (^42%) (eq. 21) (21) - 21 -A pure sample o f each o f t h e t h r e e major components was o b t a i n e d by p r e p a r a t i v e g l c . The s t r u c t u r e s a s s i g n e d t o the r e a c t i o n p r o d u c t s 7_0 and 7_1 were s u p p o r t e d by t h e i r s p e c t r a l d a t a . The uv spectrum o f the enone 7_0 e x h i b i t e d a s t r o n g a b s o r p t i o n maximum a t 236 nm, w i t h e = 12,000 (TT—»TT* t r a n s i t i o n o f a , 3 - u n s a t u r a t e d k e t o n e ) . A s t r o n g a b s o r p t i o n band a t 1670 cm ^ i n the i r spectrum o f t h i s compound a l s o i n d i c a t e d the p r e s e n c e o f an a , B - u n s a t u r a t e d k e t o n e . The i r spectrum a l s o showed a s t r o n g a b s o r p t i o n band a t 766 cm ^ w h i c h was 26 1 a t t r i b u t e d t o the t r i m e t h y l s t a n n y l group. The H nmr spectrum o f t h i s m a t e r i a l e x h i b i t e d a n i n e - p r o t o n s i n g l e t a t 60.17 ( w i t h s a t e l l i t e peaks due t o t i n c o u p l i n g , Jg n_ H=54Hz) whi c h was a t t r i b u t e d t o the s t a n n y l m e t h y l p r o t o n s . * The o l e f i n i c p r o t o n o f t h i s compound gave r i s e t o a o n e - p r o t o n t r i p l e t (J=2Hz) a t 66.22 ( w i t h s a t e l l i t e peaks, J 0 =64Hz). £>n—H The ketone 71 was found t o be a c r y s t a l l i n e s o l i d w i t h mp 50-51°C. A s t r o n g a b s o r p t i o n band a t 1701 c m - 1 i n the i r spectrum o f t h i s compound i n d i c a t e d the p r e s e n c e o f a s a t u r a t e d k e t o n e . The "'"H nmr spectrum o f t h i s m a t e r i a l e x h i b -i t e d an e i g h t e e n - p r o t o n s i n g l e t a t 6 0.04 ( w i t h s a t e l l i t e peaks * The p r o t o n c h e m i c a l s h i f t s o f the t r i m e t h y l s t a n n y l compounds are r e l a t i v e t o C H C I 3 . There a r e t h r e e n a t u r a l l y o c c u r i n g t i n i s o t o p e s w h i c h have magnetic moments (1=^): 1 1 5 S n , 1 1 7 S n , and H 9 s n . Due t o t h e i r h i g h e r r e l a t i v e abundance, 117Sn (7.67%) and H 9 g n (8.68%) a r e the i m p o r t a n t ones. As a g e n e r a l r u l e the v a l u e o f the i n d i r e c t t i n - p r o t o n c o u p l i n g s J(Sn-C-H) and J(Sn-C-C-H) i s always s l i g h t l y l a r g e r ( ~5%) f o r 1 1 9 S n t h a n f o r H 7 s n . 2 7 However, t h r o u g h o u t t h i s t h e s i s the magnitude o f t h e s e c o u p l i n g s i s always g i v e n as the average o f t h e H ^ S n and l l ^ S n v a l u e s . - 22 -due to t i n coupling, J g n_ H=49Hz) which was attributed to the stannyl methyl protons. The structure of the ketone 7_1 was further confirmed by a s a t i s f a c t o r y elemental analysis. Although the reaction of trimethylstannyllithium with the g-iodo enone 63_ led to the formation of the desired 0-t r i a l k y l s t a n n y l enone 7_0, the o v e r a l l y i e l d of the p u r i f i e d product was low. Furthermore, this transformation was not •very reproducible. Therefore, the use of other reagents to e f f e c t the formation of 11^  was considered. The conjugate addition of organocuprate reagents to 28 — 30 a ,g-unsaturated ketones i s a well known reaction. E a r l i e r work i n our laboratory had shown that the reaction of the g-iodo enones 4_ with various lithium phenylthio (alkyl) cuprate reagents resulted in the formation of the corresponding 3 g - a l k y l - a , g-unsaturated ketones 6_ (eq. 22). These phenylthio (alkyl)cuprates could be prepared e a s i l y from the reaction of 31 the corresponding a l k y l l i t h i u m reagent with phenylthiocopper. Thus, i t was of i n t e r e s t to investigate whether or not t h i s type of methodology could be extended to include the conjugate add-i t i o n of the trimethylstannyl group. - 23 -A d d i t i o n o f one e q u i v a l e n t o f s o l i d p h e n y l t h i o c o p p e r t o a c o l d (-20°C) s o l u t i o n o f t r i m e t h y l s t a n n y l l i t h i u m i n t e t r a -h y d r o f u r a n (THF) r e s u l t e d i n the f o r m a t i o n o f a dark r e d s o l u t i o n o f l i t h i u m p h e n y l t h i o ( t r i m e t h y l s t a n n y l ) c u p r a t e 7_2 (eq. 2 3 ) . S i m i l a r l y , a d d i t i o n o f one e q u i v a l e n t o f s o l i d Me3SnLi + PhSCu > PhS(Me3Sn)CuLi (23> 11 p h e n y l t h i o c o p p e r t o a c o l d (-20°C) t e t r a h y d r o f u r a n s o l u t i o n o f t r i - n - b u t y l s t a n n y l l i t h i u m gave a d a r k r e d s o l u t i o n o f l i t h i u m p h e n y l t h i o ( t r i - n - b u t y l s t a n n y l ) c u p r a t e 7_3 (eq. 2 4 ) . n-Bu3SnLi + PhSCu > PhS(n-Bu3Sn)Cul_i ( 2*> 7_3_ R e a c t i o n o f 3 - i o d o - 2 - c y c l o h e x e n - l - o n e 6_3 w i t h 1.1 e q u i v a l e n t s o f the c u p r a t e r e a g e n t s 7_2 and 7_3 i n t e t r a h y d r o -f u r a n (-20°C, 15 min; room t e m p e r a t u r e , 30 min) a f f o r d e d the c o r r e s p o n d i n g g - t r i a l k y l s t a n n y l - a , 3 - u n s a t u r a t e d k e t o n e s 70 and 74 i n 86% and 81% y i e l d , r e s p e c t i v e l y (eq. 25 and 2 6 ) . - 24 -None o f the c o r r e s p o n d i n g d i a d d i t i o n p r o d u c t s ( c f . 71) c o u l d be d e t e c t e d . The s p e c t r a l p r o p e r t i e s o f 7 0 were i d e n t i c a l w i t h t h o s e r e p o r t e d f o r the same compound p r e p a r e d e a r l i e r . 0 PhS (Me 3Sn)CuLi Q 72 63 (25) SnMe3 70 0 PhS(n-Bu 3Sn)CuLi 73 63 X (26) \ ^ S n B u n 3 74 The s t r u c t u r e o f the enone 7_4 was c o n f i r m e d by i t s s p e c t r a l d a t a . I t e x h i b i t e d a s t r o n g a b s o r p t i o n i n the uv spectrum a t 242.5 nm, w i t h e = 10,900 (TT-^TT* o f a , B -u n s a t u r a t e d k e t o n e ) . Two s t r o n g a b s o r p t i o n bands a t 167 2 and 1575 cm i n the i r spectrum a l s o i n d i c a t e d the p r e s e n c e o f an a , B - u n s a t u r a t e d k e t o n e . I n the "''H nmr spectrum the o l e f i n i c p r o t o n gave r i s e t o a o n e - p r o t o n t r i p l e t (J=2Hz) a t 66.22 - 25 -( w i t h s a t e l l i t e peaks due t o t i n c o u p l i n g , J 0 =57Hz). fan — ri S i m i l a r t r a n s f o r m a t i o n s were c a r r i e d o u t u s i n g the 3-i o d o enones 7 5-78, i n c l u s i v e , as s t a r t i n g m a t e r i a l s . The r e s u l t s a r e summarized i n Table 1. In each c a s e , the p r o d u c t e x h i b i t e d s p e c t r a l d a t a i n f u l l a c c o r d w i t h t h e a s s i g n e d s t r u c t u r e , and gave a s a t i s f a c t o r y e l e m e n t a l a n a l y s i s and/or m o l e c u l a r w e i g h t d e t e r m i n a t i o n ( h i g h r e s o l u t i o n mass s p e c t r o m e t r y ) . 0 75 X=I 79 X=SnMe. 80 X=SnBu. 77 X=I 83 X=SnMe. 84 X=SnBu. 0 76 X=I 81 X=SnMe 3 82 X=SnBu" 0 78 X=I 85 X=SnMe 3 86 X=SnBu" - 26 -A l t h o u g h the d a t a summarized i n Table 1 a r e r e l a t i v e l y s t r a i g h t f o r w a r d , i t i s a p p r o p r i a t e t o make a few comments. I t i s i n t e r e s t i n g t o note t h a t the t r i m e t h y l s t a n n y l c u p r a t e r e a g e n t 7_2 produced s l i g h t l y h i g h e r y i e l d s o f the B - t r i a l k y l -s t a n n y l enones th a n d i d i t s t r i - n - b u t y l s t a n n y l c o u n t e r p a r t 73 ( e n t r i e s 1,3,5,7, and 9 vs e n t r i e s 2,4,6,8, and 10, Table 1) . I t was found t h a t the c o n v e r s i o n o f the 3-iodo enone 78 i n t o the c o r r e s p o n d i n g ct-( t r i a l k y l s t a n n y l m e t h y l e n e ) c y c l o -hexanones 8_5 and 8_6 was n o t e n t i r e l y r e p r o d u c i b l e . The y i e l d s o f the i s o l a t e d p u r i f i e d p r o d u c t s (8_5 and 8_6) o b t a i n e d from s e v e r a l a t t e m p t s v a r i e d c o n s i d e r a b l y (31-77% f o r 85, 43-69% f o r 8_6) . Low y i e l d c o n v e r s i o n s were accompanied w i t h a c o n s i d e r a b l e amount o f u n i d e n t i f i e d s i d e p r o d u c t s . B e s t r e s u l t s were o b t a i n e d when the cru d e r e a c t i o n m i x t u r e s were chromatographed on s i l i c a g e l p r i o r t o d i s t i l l a t i o n ( a i r -bath) . The p r i n c i p l e used i n a s s i g n i n g the s t e r e o c h e m i s t r y o f the a- ( t r i a l k y l s t a n n y l m e t h y l e n e ) c y c l o h e x a n o n e s 8_5 and 86 were based on the e m p i r i c a l o b s e r v a t i o n t h a t , i n the "*"H nmr spectrum, the B - o l e f i n i c p r o t o n s c i s t o the c a r b o n y l group i n enones o f t h i s type r e s o n a t e d o w n f i e l d from t h e i r t r a n s c o u n t e r p a r t s . F o r example, the B - o l e f i n i c p r o t o n c i s t o the c a r b o n y l group o f the enone 8_7_ r e s o n a t e s a t 66.22 whereas the c o r r e s p o n d i n g p r o t o n t r a n s t o the c a r b o n y l group i n the isomer 8_8_ g i v e s r i s e t o a s i g n a l a t 6 5.60 i n the "^H nmr - 27 -T a b l e 1. R e a c t i o n o f PhS (Me 3Sn) C u L i 7_2_ and PhS (n-Bu..Sn) C u L i 73 w i t h 3-Iodo Enones E n t r y S t a r t i n g m a t e r i a l (3-iodo enone) R e a c t i o n C o n d i t i o n 3 P r o d u c t ( 3 - t r i a l k y l - ^ s t a n n y l e n o n e ) ( % Y i e l d ) 1 63 A 11 (86) 2 63 B 11 (81) 3 7_5 A 79 (84) 4 75 C 80 (79) 5 7_6 A 81 (83) 6 Z i B 82 (76) 7 77 A 83 (82) 8 77 C 84 (79) 9 78 D 8_5 ( 7 7 ) C 10 78_ B 86_ ( 6 9 ) C a A l l r e a c t i o n s were c a r r i e d o u t i n t e t r a h y d r o f u r a n a t -20°C f o r 15-30 min , and a t room te m p e r a t u r e f o r 30 min. R e a c t i o n c o n d i t i o n A: 1.1 e q u i v . o f PhS (Me^SnjCuLi 7J2; B: 1.1 e q u i v . o f PhS (n-Bu 3Sn) C u L i 73_;C: 1.3 e q u i v . o f PhS ( n - B u 3 S n ) C u L i 73; D: 1.3 e q u i v . o f P h S ( M e 3 S n ) C u L i 72. ^*The y i e l d was based on i s o l a t e d p u r i f i e d p r o d u c t s . C S e e T e x t . - 28 -3 2 spectrum. However, s i n c e o n l y one s t e r e o i s o m e r was i s o l a t e d from each o f our r e a c t i o n s a d i r e c t comparison o f g e o m e t r i c isomers ( e . g . , 8 5 vs 91) c o u l d n o t be made. 87 V H 66.22 88 Me3Sn V H ' CdHc 89 0 H<57.03 H 65.60 r ^ \ ^ S n M e 3 6 5 . 4 0 u / V u 6 5 . 9 2 -4 M 9 M U 4 H 9 90 85 0 SnMe3 91 Our assignments were based on the f o l l o w i n g arguments. The o l e f i n i c p r o t o n s a t o the m e t h y l group i n the a l k e n e 8J9 and t o the t r i m e t h y l s t a n n y l group o f the stannane 9_0 r e s o n a t e 33 34 a t 6 5 . 4 0 and 6 5 . 9 2 , r e s p e c t i v e l y . Thus, c h a n g i n g the a - s u b s t i t u e n t on the hexene d e r i v a t i v e from m e t h y l t o t r i -m e t h y l s t a n n y l caused a change i n the c h e m i c a l s h i f t o f the o l e f i n i c p r o t o n ( A = 0 . 5 2 ppm). T h e r e f o r e , on the b a s i s o f t h i s c o m p a r i s o n , a l o n g w i t h the o b s e r v a t i o n r e g a r d i n g the c h e m i c a l s h i f t s o f the o l e f i n i c p r o t o n s i n the enones 87 and 8 8 , the o l e f i n i c p r o t o n s o f the t r i m e t h y l s t a n n y l enone - 29 -85 and i t s isomer 91 might be e x p e c t e d t o r e s o n a t e a t a p p r o x i m a t e l y 67.14 (6.62 + 0.52) and 66.12 (5.60 -+ 0.52), r e s p e c t i v e l y . The o b s e r v e d v a l u e was 6 7.03, thus p r o v i d i n g e x c e l l e n t e v i d e n c e f o r the s t e r e o c h e m i s t r y o f 8_5 as shown. In the "^H nmr spectrum o f the a - ( t r i - n - b u t y l s t a n n y l -methylene) c y c l o h e x a n o n e 8_6, the o l e f i n i c p r o t o n r e s o n a t e d a t 67.08. T h i s v a l u e d i f f e r e d from t h a t o f the c o r r e s p o n d i n g s i g n a l i n the 0 - t r i m e t h y l s t a n n y l ketone 85_ by o n l y 0.05 ppm. T h i s d i f f e r e n c e would appear t o be too s m a l l f o r the two compounds t o have the o p p o s i t e s t e r e o c h e m i s t r y . F u r t h e r m o r e , r e c e n t work i n our l a b o r a t o r y has shown t h a t the r e a c t i o n o f 78_ w i t h l i t h i u m p h e n y l t h i o ( c y c l o p r o p y l ) c u p r a t e proceeds i n a c o m p l e t e l y s t e r e o s e l e c t i v e manner w i t h r e t e n t i o n o f 3b c o n f i g u r a t i o n (eq. 2 7 ) . Thus i t seems c l e a r t h a t compounds (27) 78 92 85 and 8_6_ p o s s e s s the s t e r e o c h e m i s t r y as shown. We have a l s o e x p l o r e d the use o f o t h e r r e a g e n t s t o e f f e c t the c o n v e r s i o n o f the 0 - i o d o enones 4 i n t o t h e i r 3 - t r i a l k y l -s t a n n y l d e r i v a t i v e s 11. Treatment of a c o l d (-48°C) t e t r a -- 30 -h y d r o f u r a n s o l u t i o n o f t r i m e t h y l s t a n n y l l i t h i u m w i t h 0.5 35 e q u i v a l e n t s o f d i m e t h y l s u l f i d e - c u p r o u s bromide r e s u l t e d i n the immediate f o r m a t i o n o f a d a r k r e d s o l u t i o n o f the l i t h i u m b i s ( t r i m e t h y l s t a n n y l ) c u p r a t e r e a g e n t 93 (eq. 2 8 ) . * 2Me 3 SnLi + CuBr.SMe 2 > (Me3Sn)2CuLi.SMe2 (28) 93 R e a c t i o n o f 3 - i o d o - 2 - c y c l o h e x e n - l - o n e 6_3 w i t h 1.1 e q u i v a l e n t s o f 9_3_ i n t e t r a h y d r o f u r an (-48°C, l h ; -20°C, l h ) a f f o r d e d the 0 - t r i m e t h y l s t a n n y l enone 7_0 i n 76% y i e l d (eq. 29). A g l c a n a l y s i s of t h i s m a t e r i a l showed t h a t i t was c o n t a m i n a t e d w i t h a s m a l l amount (^6%) o f the d i a d d i t i o n p r o d u c t 71. * R e c e n t l y , Hudec r e p o r t e d the a d d i t i o n o f t r i m e t h y l s t a n n y l -l i t h i u m i n the p r e s e n c e o f cuprous i o d i d e t o a , 3 - u n s a t u r a t e d k e t o n e s . 36 - 31 -However, s i n c e two e q u i v a l e n t s o f t r i m e t h y l s t a n n y l l i t h i u m a r e r e q u i r e d t o p r e p a r e 1 e q u i v a l e n t o f 93_, i t seems c l e a r t h a t PhS (Me^Sn) C u L i 7_2 i s the p r e f e r r e d r e a g e n t . A l t e r n a t i v e l y , t r e a t m e n t o f a c o l d (-48°C) t e t r a h y d r o f u r a n s o l u t i o n o f t r i m e t h y l s t a n n y l l i t h i u m w i t h 1 e q u i v a l e n t o f 35 d i m e t h y l s u l f i d e - c u p r o u s bromide a f f o r d e d a dark r e d s o l u t i o n o f the t r i m e t h y l s t a n n y l c o p p e r r e a g e n t 9_4 (eq. 3 0 ) . R e a c t i o n Me3SnLi + CuBr-SMe2 > Me3SnCu.|_iBr-SMe2 94 o f 3 - i o d o - 2 - c y c l o h e x e n - l - o n e 6_3 (-48°C, 2h; -20°C, l h ; room t e m p e r a t u r e , l h ) w i t h 1.3 e q u i v a l e n t s o f 9_4 gave the 3-t r i a l k y l s t a n n y l enone 70_ i n 84% y i e l d (eq. 31) . S i m i l a r l y , 0 Me3SnCu-LiBr.SMe2 94 (31) SnMe3 63 70 - 32 -a number o f o t h e r g-iodo enones 7_6, 7_7, and 7_8 were c o n v e r t e d e f f i c i e n t l y i n t o the c o r r e s p o n d i n g g - t r i m e t h y l s t a n n y l enones 81^ , 8 3 > a n d 85/ r e s p e c t i v e l y . The r e s u l t s a r e summarized i n T a b l e 2. In a l l c a s e s , the y i e l d s o f the i s o l a t e d p u r i f i e d p r o d u c t s were comparable w i t h those o b t a i n e d from the c u p r a t e r e a g e n t 72. I n p a r t i c u l a r , the c o n v e r s i o n o f 7_8 i n t o the a - ( t r i m e t h y l -s t a n n y l m e t h y l e n e ) c y c l o h e x a n o n e 8_5 w i t h the t r i m e t h y l s t a n n y l -copper r e a g e n t 9_4 was found t o be much more r e p r o d u c i b l e than t h a t employing 7_2. I t i s however, of i n t e r e s t t o note t h a t when the copper r e a g e n t 9_4 was p r e p a r e d a t t e m p e r a t u r e s h i g h e r than -48°C (e.g., -20°C) v a r y i n g amounts of the g-iodo enone s t a r t i n g m a t e r i a l s were r e c o v e r e d . I t was a l s o found t h a t f o r m a t i o n o f the g - t r i m e t h y l s t a n n y l enone 8_3 under r e a c t i o n c o n d i t i o n s i d e n t i c a l w i t h those used - 33 -Table 2. Reaction of Me 3SnCu•LiBr'SMe 2 3-Iodo Enones. 94 with Entry Starting material Reaction (3-iodo enone) Condition Product (3-trimethyl-stannyl enone) 0 I Y i e l d ) b 1 63 A 70 (84) 2 76 A 81 (80) 3 77_ B 8_3 (82) 4 78 C 85 (75) A l l reactions employed 1.3 equiv. of Me3SnCu•LiBr?SMe^-94. Reaction condition A: tetrahydrofuran was used as solvent; -48°C, 2h; -20°C, l h ; room temperature,lh; B: tetrahydro-furan - HMPA in a r a t i o of 3:1 was used as solvent; -48°C, 2h; -20°C, l h ; room temperature, l h ; C: tetrahydrofuran was the solvent; -48°C, 2h. k The y i e l d was based on iso l a t e d p u r i f i e d products. The spectral properties ( i r , ^"H nmr) of these materials were i d e n t i c a l with those of the same compounds reported e a r l i e r . - 34 -f o r the g - i o d o enones 6_3 and 7_5 gave i n a d d i t i o n t o t h e d e s i r e d p r o d u c t a s i g n i f i c a n t amount o f s t a r t i n g m a t e r i a l . However, the a d d i t i o n o f hexamethylphosphoramide (HMPA) as co-solvent improved the e f f i c i e n c y o f t h i s c o n v e r s i o n ( e n t r y 3, T a b l e 2 ) . I t has been w e l l e s t a b l i s h e d t h a t a , g - u n s a t u r a t e d c a r b o n y l compounds e x h i b i t i n t e n s e a b s o r p t i o n bands i n t h e i r 37 u l t r a v i o l e t s p e c t r a (TT—>TT * t r a n s i t i o n ) . The w a v e l e n g t h a t w hich the a b s o r p t i o n maximum (A ) o c c u r s can u s u a l l y be ^ max J p r e d i c t e d w i t h a good degree of a c c u r a c y by use o f the Woodward-38 3 9 F i e s e r r u l e s . ' For example, a c c o r d i n g t o t h e s e r u l e s , a g - a l k y l s u b s t i t u e n t causes a b a t h o c h r o m i c s h i f t (a s h i f t t o l o n g e r wavelength) of ^12nm i n the a b s o r p t i o n maximum, 37 r e l a t i v e t o t h a t o f the g - u n s u b s t i t u t e d compound. However, s i n c e no g - t r i a l k y l s t a n n y l enones had been r e p o r t e d i n the •chemical l i t e r a t u r e p r i o r t o our i n v e s t i g a t i o n , n o t h i n g was known about the e f f e c t o f a g - t r i a l k y l s t a n n y l s u b s t i t u e n t on the p o s i t i o n o f the TT-MT * a b s o r p t i o n maximum o f an a , g - u n s a t u r a t e d k e tone. Some of the r e s u l t s we have o b t a i n e d a l o n g w i t h a number of p a r e n t g - u n s u b s t i t u t e d enones a r e summarized i n T a b l e 3. In c o n n e c t i o n w i t h the d a t a t a b u l a t e d i n Table 3 the f o l l o w i n g p o i n t s s h o u l d be n o t e d . Compared w i t h the c o r r e s -p onding g - u n s u b s t i t u t e d enones, the a b s o r p t i o n maxima o f the g - t r i a l k y l s t a n n y l enones e x h i b i t e d a s i g n i f i c a n t b a t h ochromic s h i f t . I n g e n e r a l , f o r a g i v e n enone, the magnitude o f the - 35 -in c r e m e n t a s s o c i a t e d w i t h t h e B - t r i - n - b u t y l s t a n n y l group (17-22.5 nm) was c o n s i s t e n t l y l a r g e r than t h a t o f the t r i m e t h y l s t a n n y l group (10-16.5 nm). F o r example, 3 - t r i - n -b u t y l s t a n n y l - 2 - m e t h y l - 2 - c y c l o h e x e n - l - o n e 8_0 showed an a b s o r p t i o n maximum a t 256 nm w h i c h was 22 nm h i g h e r t h a n t h a t o f the p a r e n t 2 - m e t h y l - 2 - c y c l o h e x e n - l - o n e 9_5 ( e n t r i e s 4 and 6, Ta b l e 3 ) . The c o r r e s p o n d i n g 3 - t r i m e t h y l s t a n n y l enone 7_9 had an a b s o r p t i o n maximum a t 250 nm whi c h was 16 nm h i g h e r than t h a t o f the p a r e n t enone 9_5 ( e n t r i e s 4 and 5, Table 3 ) . I t was a l s o found t h a t the magnitude of the e x t i n c t i o n c o e f f i c i e n t s ( e ) a s s o c i a t e d w i t h the a b s o r p t i o n maxima o f the 3 - t r i - n - b u t y l s t a n n y l enones were c o n s i s t e n t l y l e s s t h a n t h o s e o f t h e c o r r e s p o n d i n g 3 - t r i m e t h y l s t a n n y l compounds ( e n t r i e s 3,6,9,12, and 15 vs e n t r i e s 2,5,8,11, and 14, Table 3 ) . Owing t o the l a c k o f uv s p e c t r a l d a t a on 3 - t r i a l k y l s t a n n y l - c t , 3 - u n s a t u r a t e d c a r b o n y l compounds, i t i s n o t c e r t a i n whether o r not the above o b s e r v a t i o n s r e p r e s e n t g e n e r a l t r e n d s . However, t h e uv s p e c t r a o f s e v e r a l 3 - t r i a l k y l s t a n n y l - a , 3 - u n s a t u r a t e d e s t e r s w i l l be d i s c u s s e d i n a l a t t e r s e c t i o n o f t h i s t h e s i s . I n g e n e r a l , t h e t r i a l k y l s t a n n y l r e a g e n t s PhS(Me^Sn)CuLi 72, PhS (n-Bu 3Sn) C u L i 1_2_, (Me 3Sn) 2 C u L i • SMe 2 93, and Me 3SnCu • L i B r • SMe 2  94 c o u l d be p r e p a r e d i n a s i m p l e manner. F u r t h e r m o r e , t h e s e r e a g e n t s r e a c t e d w i t h c y c l i c 3-iodo enones t o produce the c o r r e s p o n d i n g 3 - t r i a l k y l s t a n n y l enones, a h i t h e r t o unknown c l a s s o f compounds, i n good y i e l d . These 3 - t r i a l k y l s t a n n y l - 36 -T a b l e 3. The UV A b s o r p t i o n Maxima (* m a x' °- Some V - T r i a l k y l s t a n n y l Enones and T h e i r P a r e n t B - U n s u b s t i t u t e d Enones E n t r y a, B - U n s a t u r a t e d k e t o n e Observed X (nm)(e) max D i f f e r e n c e i n xmax between 6 - t r i a l k y l s t a n n l enones and t h e i r p a r e n t B-unsub-s t i t u t e d enones R e f e r e n c e 226 (10,400) 40 236 (12,000) 10 SnMei 242.5 (10,900) 16.5 SnBu n 3 234 41 250 (14,300) 16 SnMe3 256 (12,00) 22 SnBun3 218 (9,500) 42 96 81 S n M e 3 0 - 37 -233 (15,200) 15 10 11 12 13 14 15 82 SnBu n 3 97 0 83 SnMeg 0 84 SnBu 3 98 0 235 (12,100) 226 (8,550) 242.5 (15,800) 246.5 (13,200) 231 (7,550) SnMe 3 246 (8, 300) 85 250 (7,400) 17 16.5 20.5 15 19 43 44 aThe uv spectra of the B - t r i a l k y l s t a n n y l enones were recorded using methanol solutions. For the B-unsubstituted enones ethanol was the solvent. - 38 -enones were found t o be s t a b l e and c o u l d be s t o r e d under an atmosphere o f argon i n a f r e e z e r f o r s e v e r a l months w i t h o u t s u b s t a n t i a l d e c o m p o s i t i o n . However, th e s e compounds s h o u l d be h a n d l e d w i t h c a r e s i n c e i t i s w e l l known t h a t o r g a n o t i n compounds ar e t o x i c . ^ I I I P r e p a r a t i o n o f l - L i t h i o - 3 - t e r t - b u t y l d i m e t h y l s i l o x y -1,3-c y c l o h e x a d i e n e 111 and i t s R e a c t i o n w i t h E l e c t r o p h i l e s As mentioned p r e v i o u s l y , t h e f o r m a t i o n o f v i n y l a n i o n s by the t r a n s m e t a l a t i o n o f t r i l k y l v i n y l s t a n n a n e s i s a w e l l known p r o c e s s . ^ F o r example, t r e a t m e n t of the stannane 9_9 w i t h 1 e q u i v a l e n t o f n - b u t y l l i t h i u m r e s u l t e d i n the f o r m a t i o n o f the v i n y l l i t h i u m r e a g e n t 100 (eq. 3 2 ) . 6 a I t can r e a d i l y (32) 99 100 be seen t h a t the B - t r i a l k y l s t a n n y l enones 11_ i n c o r p o r a t e i n t o t h e i r s t r u c t u r e s the t r i a l k y l v i n y l s t a n n y l m o i e t y . T h e r e f o r e , w i t h t h e s e l a t t e r compounds a t hand, i t was o f i n t e r e s t t o i n v e s t i g a t e whether o r n o t they c o u l d s e r v e as e f f i c i e n t - 39 -p r e c u r s o r s t o the 0 - a c y l v i n y l a n i o n e q u i v a l e n t 62 (Scheme 1) X -> OSiR--> c v ^ S n R 3 y ^ S n R 3 Li i i 66 62 Scheme 1 Our i n i t i a l work i n t h i s a r e a employed the e n o l t r i m e t h y l -s i l y l d e r i v a t i v e 101. Treatment o f 3 - t r i - n - b u t y l s t a n n y l - 2 -c y c l o h e x e n - l - o n e 7_4 w i t h 1.1 e q u i v a l e n t s o f l i t h i u m d i i s o p r o p y l -amide (LDA) i n t e t r a h y d r o f u r a n (-78°C, l h ; 0°C, 30 min) f o l l o w e d by the a d d i t i o n o f t r i m e t h y l s i l y l c h l o r i d e i n t r i e t h y l a m i n e (-78°C t o room t e m p e r a t u r e , l h ) a f f o r d e d the e n o l s i l y l e t h e r 46 101 in 93% y i e l d (eq. 3 4 ) . T h i s r e a c t i o n was v e r y c l e a n , 74 101 - 40 -p r o d u c i n g a s i n g l e e n o l s i l y l e t h e r which c o u l d be p u r i f i e d by a s i m p l e d i s t i l l a t i o n . F u r t h e r m o r e , the p r o d u c t 101 was q u i t e s t a b l e . The s t r u c t u r e o f the e n o l s i l y l e t h e r 101 was s u p p o r t e d by i t s s p e c t r a l d a t a . The "*"H nmr spectrum o f t h i s compound e x h i b i t e d a n i n e - p r o t o n s i n g l e t a t 6 0.16* which was a t t r i b u t e d t o the t r i m e t h y l s i l o x y group. The C-2 and C-4 o l e f i n i c p r o t o n s o f 101 gave r i s e t o two on e - p r o t o n m u l t i p l e t s a t 6 5.83 ( w i t h s a t e l l i t e s due t o t i n c o u p l i n g , Jg n_ H=60Hz) and 64.86, r e s p e c t i v e l y . The i r spectrum o f t h i s m a t e r i a l showed a medium i n t e n s i t y a b s o r p t i o n band a t 1637 cm ^. T r a n s m e t a l a t i o n o f 101 was a c c o m p l i s h e d by t r e a t m e n t (-90°C, 2h; 0°C, 30 min) o f a t e t r a h y d r o f u r a n s o l u t i o n o f t h i s compound w i t h 1.1 e q u i v a l e n t s o f n - b u t y l l i t h i u m . P r o t o n a t i o n o f the r e s u l t a n t m i x t u r e w i t h a s o l u t i o n o f a c e t i c a c i d (1.1 e q u i v a l e n t s ) i n e t h e r a f f o r d e d an 81% y i e l d o f a y e l l o w o i l . A g l c a n a l y s i s o f t h i s m a t e r i a l i n d i c a t e d t h a t i t was composed o f a m i x t u r e o f the e n o l s i l y l 46b c 47 e t h e r 102 ' and the ketone 103 i n a r a t i o o f 1:5, r e s p e c t i v e l y (eq. 35). T e t r a - n - b u t y l t i n and o t h e r minor 0SiMe3 0SlMe3 pg-BuLi ; n B u n 3 2)H0Ac > + n-Bu 4Sn (35) SiMe*-101 102 103 * The c h e m i c a l s h i f t s o f a l l e n o l s i l y l e t h e r s d e s c r i b e d h e r e i n a r e r e l a t i v e t o CHC1 3. - 41 -impurities were also present. The two major components were separated by careful d i s t i l l a t i o n (air-bath) of the mixture. The structures assigned to the reaction products 102 and 103 were supported by the spectral data. The "^H nmr spectrum of the enol s i l y l 46b c ether 102 ' showed a one-proton multiplet at 6 4.87 which was attributed to the C - l o l e f i n i c proton. The C-3 and C-4 protons gave r i s e to a two-proton multiplet centered at 6 5.73. A nine-proton s i n g l e t due to the trimethylsiloxy group appeared at 6 0.15. The i r spectrum of t h i s material exhibited two weak absorption bands at 1643 and 1592 cm . 47 The i r spectrum of 103 exhibited two absorption bands at 1675 and 1595 cm which indicated the presence of an a , 3-unsaturated ketone f u n c t i o n a l i t y . In the "^H nmr spectrum of 103 the o l e f i n i c proton gave r i s e to a one-proton t r i p l e t (J=2Hz) at 6 6.22 while the t r i m e t h y l s i l y l group gave r i s e to a nine-proton s i n g l e t at 6 0.10. The ( i n i t i a l l y unexpected) formation of the ketone 103 may be r a t i o n a l i z e d as follows. Reaction of the i n i t i a l l y formed v i n y l l i t h i u m reagent 104 with the t r i m e t h y l s i l y l f u n c t i o n a l i t y of another molecule of 104 would generate the dianion 105 and the v i n y l s i l a n e 106. A second oxygen to carbon migration of the t r i m e t h y l s i l y l group between 105 and 106 would give the enolate 107. Protonation of 107 would then afford the ketone 103 (Scheme 2). - 42 -When th e t r a n s m e t a l a t i o n o f 101 was c a r r i e d o u t a t -78 C f o r l h , and the r e s u l t a n t m i x t u r e was quenched (HOAc) a t t h a t t e m p e r a t u r e , the e n o l s i l y l e t h e r 102 and the ketone 103 were formed i n a r a t i o o f 2:1, r e s p e c t i v e l y . Thus, a l t h o u g h the t r a n s m e t a l a t i o n o f 101 d i d g i v e the e x p e c t e d e n o l s i l y l e t h e r 102, even a t low t e m p e r a t u r e s a c o n s i d e r a b l e amount o f the u n d e s i r e d ketone 103 was a l s o formed. I t has been shown t h a t the t e r t - b u t y l d i m e t h y l s i l o x y group, due t o the s t e r i c h i n d r a n c e o f the t e r t - b u t y l s u b s t i t u e n t , i s much more s t a b l e than the t r i m e t h y l s i l o x y group towards 21 n u c l e o p h i l i c r e a g e n t s . T h e r e f o r e , i t was hoped t h a t p r o t e c t i o n o f the c a r b o n y l group o f 74 as t h e e n o l t e r t - b u t y l d i m e t h y 1 s i l y l - 43 -e t h e r would p r e v e n t the f o r m a t i o n o f the ketone 103. T r e a t -ment o f 3 - t r i - n - b u t y l s t a n n y l - 2 - c y c l o h e x e n - l - o n e 7_4 w i t h 1.1 e q u i v a l e n t s o f l i t h i u m d i i s o p r o p y l a m i d e (LDA) i n t e t r a h y d r o -f u r a n (-78°C, l h ; 0°C, 30 min) f o l l o w e d by the a d d i t i o n o f t e r t - b u t y l d i m e t h y l s i l y l c h l o r i d e i n hexamethylphosphoramide (HMPA) (-78°C t o room t e m p e r a t u r e , 2h) a f f o r d e d the e n o l s i l y l e t h e r 108 i n 94% y i e l d (eq. 3 6 ) . The s t r u c t u r e 1) LDA SnBun3 2) t-BuMe2SiCI SiMe 2Bu t SnBun3 (36) 74 108 a s s i g n e d t o t h e e n o l s i l y l e t h e r 108 was s u p p o r t e d by i t s s p e c t r a l d a t a . The 1 H nmr spectrum o f 108 e x h i b i t e d two one - p r o t o n m u l t i p l e t s a t 64.86 and 65.85 (the l a t t e r w i t h s a t e l l i t e peaks due t o t i n c o u p l i n g , J" S n_ H=60Hz) wh i c h were a t t r i b u t e d t o the C-4 and C-2 o l e f i n i c p r o t o n s , r e s p e c t i v e l y . A s i x - p r o t o n s i n g l e t due t o the s i l y l m e t h y l s appeared a t 60.08.while a n i n e - p r o t o n s i n g l e t due t o t h e t e r t - b u t y l m e t h y l s appeared a t 6 0.89. The i r spectrum o f t h i s m a t e r i a l e x h i b i t e d a weak a b s o r p t i o n band a t 1640 cm ^. - 44 -Treatment o f the e n o l s i l y l e t h e r 108 w i t h 1.1 e q u i v a l e n t s o f n - b u t y l l i t h i u m i n t e t r a h y d r o f u r a n (-78°C, 1.5h; 0°C, 30 m i n ) , f o l l o w e d by p r o t o n a t i o n o f the r e s u l t a n t t r a n s m e t a l a t i o n p r o d u c t w i t h 1.1 e q u i v a l e n t s o f a c e t i c a c i d a f f o r d e d the e n o l s i l y l e t h e r 109 i n 87% y i e l d (eq. 3 7 ) . T h i s r e a c t i o n 0SiMe2But Dp-BuLi > 0SiMe2But + n-Bi^ Sn (37) 108 109 was v e r y c l e a n and the p r o d u c t c o u l d be s e p a r a t e d from t e t r a -n - b u t y l t i n by a s i m p l e d i s t i l l a t i o n ( a i r - b a t h ) . None o f t h e ketone w h i c h would have r e s u l t e d from m i g r a t i o n o f the , j t e r t -b u t y l d i m e t h y l s i l y l group ( c f . 103) c o u l d be d e t e c t e d . The s t r u c t u r e o f 109 was c o n f i r m e d by i t s s p e c t r a l d a t a . The ''"H nmr spectrum o f t h i s m a t e r i a l showed a one-pr o t o n m u l t i p l e t a t 6 4.87 w h i c h was a t t r i b u t e d t o t h e C - l o l e f i n i c p r o t o n . The C-3 and C-4 o l e f i n i c p r o t o n s appeared as a two - p r o t o n m u l t i p l e t c e n t e r e d a t 6 5.78. A s i x - p r o t o n s i n g l e t due t o th e s i l y l m e t h y l groups appeared a t 6 0.08 w h i l e a n i n e - p r o t o n s i n g l e t due t o t h e t e r t - b u t y l m e t h y l s appeared a t 6 0.89. The i r spectrum o f t h i s m a t e r i a l e x h i b i t e d two weak bands a t - 45 -1643 and 1590 cm" 1. The e n o l s i l y l e t h e r 110 was p r e p a r e d (96%) v i a a p r o c e d u r e i d e n t i c a l w i t h t h a t employed f o r t h e p r e p a r a t i o n o f 108 (eq. 3 8 ) . T r a n s m e t a l a t i o n o f 110 was a c c o m p l i s h e d 1) LDA SnMeo 2) t-BuMe2SiCI SiMe 2Bu t SnMe 3 (38) 70 110 by t r e a t m e n t o f a t e t r a h y d r o f u r a n s o l u t i o n of t h i s compound w i t h 1.1 e q u i v a l e n t s o f m e t h y l l i t h i u m a t -78°C f o r l h . P r o t o n a t i o n o f t h e r e s u l t a n t v i n y l l i t h i u m i n t e r m e d i a t e 111 (HOAc, 1.1 e q u i v a l e n t s ) a f f o r d e d t h e e n o l s i l y l e t h e r 109 i n 84% y i e l d . The s p e c t r a l p r o p e r t i e s o f t h i s m a t e r i a l were i d e n t i c a l w i t h t h o s e o f the same compound p r e p a r e d p r e v i o u s l y . 0SiMe9Bu i n - 46 -Thus, t r a n s m e t a l a t i o n o f t h e e n o l s i l y l e t h e r s 108 and 110 was r e a d i l y a c c o m p l i s h e d by t r e a t m e n t (THF, -78°C, 1-1.5h) o f t h e s e s u b s t a n c e s w i t h 1.1 e q u i v a l e n t s o f n - b u t y l l i t h i u m and m e t h y l l i t h i u m , r e s p e c t i v e l y . P r o t o n a t i o n (HOAc) o f the r e s u l t a n t v i n y l l i t h i u m i n t e r m e d i a t e 111 a f f o r d e d 2 - t e r t - b u t y l d i m e t h y l s i l o x y - 1 , 3 - c y c l o h e x a d i e n e 109 i n good y i e l d . More i m p o r t a n t l y , the i n t e r m e d i a t e 111 a l s o r e a c t e d smoothly w i t h a v a r i e t y o f o t h e r e l e c t r o p h i l i c r e a g e n t s t o produce the c o r r e s p o n d i n g s u b s t i t u t e d 1,3-cyc.lohexadienes. Some o f the r e s u l t s a r e summarized i n Tab l e 4. A t y p i c a l p r o c e d u r e f o l l o w s . To a c o l d (-78°C), s t i r r e d s o l u t i o n o f 110 (0.27 mmol) i n 5 mL o f anhydrous t e t r a h y d r o f u r a n , under an atmosphere o f a r g o n , was added d r o p w i s e a s o l u t i o n o f m e t h y l l i t h i u m i n e t h e r (0.30 mmol) and the r e s u l t a n t y e l l o w s o l u t i o n was s t i r r e d a t -78°C f o r l h . Cyclohexanone (0.35 mmol) was added and the r e a c t i o n m i x t u r e was s t i r r e d f o r an a d d i t i o n a l p e r i o d o f l h . A f t e r s u c c e s s i v e a d d i t i o n o f s a t u r a t e d aqueous sodium b i c a r b o n a t e and e t h e r , the m i x t u r e was a l l o w e d t o warm t o room t e m p e r a t u r e . The e t h e r s o l u t i o n was then washed w i t h s a t u r a t e d aqueous sodium b i c a r b o n a t e and d r i e d o ver anhydrous magnesium s u l f a t e . E v a p o r a t i o n o f s o l v e n t , f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h ) o f the r e s i d u a l o i l gave 76 mg (92%) o f pure 1 - ( 1 - h y d r o x y c y c l o h e x y l ) - 3 - t e r t -b u t y l d i m e t h y l s i l o x y - 1 , 3 - c y c l o h e x a d i e n e 120. The s t r u c t u r e - 47 -o f 120 was c o n f i r m e d by i t s s p e c t r a l d a t a . The "'"H nmr spectrum o f t h i s compound e x h i b i t e d two one-pr o t o n m u l t i p l e t s a t 6 4.82 and 6 5.74 w h i c h were a t t r i b u t e d t o the C-4 and C-2 o l e f i n i c p r o t o n s , r e s p e c t i v e l y . A broad u n r e s o l v e d t e n - p r o t o n s i g n a l c e n t e r e d a t 61.56 was a t t r i b u t e d t o the c y c l o h e x y l methylene p r o t o n s . The uv spectrum o f t h i s m a t e r i a l e x h i b i t e d a s t r o n g a b s o r p t i o n a t 268 nm, w i t h e = 5,250 (TT-^ TT * o f 1 , 3 - d i e n e ) . Two weak a b s o r p t i o n bands a t 1653 and 1610 cm ^ i n the i r spectrum a l s o i n d i c a t e d the p r e s e n c e o f a 1,3-diene system. There a l s o appeared an a b s o r p t i o n band a t 3420cm w h i c h was due t o the hydroxy f u n c t i o n a l i t y . S i m i l a r l y , the v i n y l l i t h i u m i n t e r m e d i a t e 111 a l s o r e a c t e d w i t h a v a r i e t y o f o t h e r e l e c t r o p h i l i c r e a g e n t s . The r e s u l t s a r e summarized i n Ta b l e 4. A l l o f the p r o d u c t s l i s t e d i n Tab l e 4 gave s p e c t r a l d a t a i n f u l l a c c o r d w i t h the a s s i g n e d s t r u c t u r e s . Each o f t h e s e p r o d u c t s a l s o gave a s a t i s f a c t o r y m o l e c u l a r w e i g h t d e t e r m i n a t i o n ( h i g h r e s o l u t i o n mass s p e c t r o m e t r y ) . 120 - 48 -In c o n n e c t i o n w i t h the d a t a summarized i n T a b l e 4, t h e f o l l o w i n g p o i n t s s h o u l d be n o t e d . A l t h o u g h , t h e r e a c t i o n o f the v i n y l l i t h i u m r e a g e n t 111 w i t h c a r b o n y l compounds ( e n t r i e s 5-9, T a b l e 4) proceeded t o c o m p l e t i o n a t -78°C ( l h ) , the a l k y l a t i o n r e a c t i o n s ( e n t r i e s 1-4, T a b l e 4) as w e l l as t h e 48 r e a c t i o n w i t h dimethyl(methylene)ammonium i o d i d e ( e n t r y 10, T a b l e 4) were c a r r i e d o ut f o r l h a t -78°C and l h a t room te m p e r a t u r e . G l c a n a l y s i s o f the crude r e a c t i o n p r o d u c t s showed t h a t e s s e n t i a l l y o n l y one p r o d u c t , c o n t a m i n a t e d w i t h s m a l l amounts o f the p r o t o n a t e d s p e c i e s 109, was o b t a i n e d from each r e a c t i o n . I n g e n e r a l , the p r o d u c t s c o u l d be p u r i f i e d by a s i m p l e d i s t i l l a t i o n ( a i r - b a t h ) . Of t h e two p r e c u r s o r s (108, 110) o f the v i n y l l i t h i u m 111, the use o f 110 was somewhat more c o n v e n i e n t s i n c e the r e l a t i v e l y v o l a t i l e t e t r a m e t h y l t i n c o u l d be s e p a r a t e d v e r y e a s i l y from t h e v a r i o u s r e a c t i o n p r o d u c t s 112. In f a c t , i n some c a s e s m e t h y l l i t h i u m was used f o r the t r a n s m e t a l a t i o n o f 108, s i n c e m e t h y l t r i - n -b u t y l t i n c o u l d be s e p a r a t e d from the r e a c t i o n p r o d u c t s more r e a d i l y t h a n t e t r a - n - b u t y l t i n ( e n t r i e s 3 and 4, Table 4 ) . I t was found t h a t t r e a t m e n t o f t h e v i n y l l i t h i u m r e a g e n t 111 w i t h l - b r o m o - 4 - c h l o r o b u t a n e gave a m i x t u r e o f t h e bromide 116 and the c h l o r i d e 117 i n a r a t i o o f 13:87, r e s p e c t i v e l y ( e n t r y 4, T a b l e 4 ) . The i d e n t i t y o f t h i s m i x t u r e was s u p p o r t e d by i t s s p e c t r a l d a t a . The 1 H nmr spectrum of t h i s m a t e r i a l e x h i b i t e d two o n e - p r o t o n m u l t i p l e t s a t 6 4.75 and 6 5.44 w h i c h - 49 -Tab l e 4. R e a c t i o n o f l - L i t h i o - 3 - t e r t - b u t y l d i n i e t h y l s i l o x y -1 , 3 - c y c l o h e x a d i e n e 111 w i t h E l e c t r o p h i l e s OSiMe2But 111 -> OSiMe2But 112 E n t r y P r e c u r s o r o f 111 E l e c t r o p h i l e P r o d u c t E i n 112 (% Y i e l d ) ' 1 2 3 4 5 6 7 108  110 1 0 8 b 1 0 8 b 108  110 108,110 10 108 110 CH 3 I C H 3 ( C H 2 ) 3 B r R ( C H 2 ) 2 B r C C l ( C H 2 ) 4 B r C 6H 5CHO 113  114 115 CH 3" C H 3 ( C H 2 ) 3 -R ( C H 2 ) 2 -116(X=Br) X ( C H 2 ) 4 -+117(X=Cl) d 118 - - C 5 H 1 1 C H ° 119 cy c l o h e x a n o n e 120 108,110 c y c l o p e n t a n o n e 121 2 - c y c l o h e x e n -1-one 122 (CH 3) 2N=CH 2 I " 123 C gH 5CH(OH) n-C cH,.CH(OH) — b 11 1-hydroxy-c y c l o h e x y l 1-hydroxy-c y c l o p e n t y l Hydroxy-2-c y c l o h e x e n y l ( C H 3 ) 2 N C H 2 ~ (86) (72) (72) (78) (92) (71) (91,92) (81,88) (84) (81) - 50 -Y i e l d o f d i s t i l l e d p u r i f i e d p r o d u c t . In t h i s c a s e the t r a n s m e t a l a t i o n o f 108 was a c c o m p l i s h e d w i t h 1.1 e q u i v . o f m e t h y l l i t h i u m (THF, -78°C, l h ) . R = 2 - c y c l o p e n t e n y l . T h i s p r o d u c t c o n s i s t e d o f a m i x t u r e o f the bromide 116 and the c h l o r i d e 117 i n a r a t i o o f 13:87, r e s p e c t i v e l y . - 51 -116 X=Br 117 X=C1 were a t t r i b u t e d t o the C-4 and C-2 o l e f i n i c p r o t o n s , r e s p e c t -i v e l y . There a l s o appeared i n t h e "'"H nmr spectrum two t r i p l e t s (both J=6Hz) a t 63.40 and 63.52. These were a t t r i b u t e d t o the bromomethylene and c h l o r o m e t h y l e n e p r o t o n s o f 116 and 117, r e s p e c t i v e l y . The i r spectrum of t h i s m a t e r i a l e x h i b i t e d two weak a b s o r p t i o n bands a t 1655 and 1610 cm . H y d r o l y s i s o f a crude p r e p a r a t i o n o f the e n o l s i l y l e t h e r 114 (prepared from 108) w i t h IN h y d r o c h l o r i c a c i d i n t e t r a h y d r o f u r a n f o r l h a t room tem p e r a t u r e gave, a f t e r removal of t e t r a - n - b u t y l t i n , 3 - n - b u t y l - 2 - c y c l o h e x e n - l - o n e 49 124 i n 67% o v e r a l l y i e l d (eq. 3 9 ) . The enone 124 gave aq. HCI (39) 108 114 124 s p e c t r a l d a t a i n f u l l a c c o r d w i t h t h e a s s i g n e d s t r u c t u r e . In t he "*"H nmr spectrum o f 124 the o l e f i n i c p r o t o n gave r i s e t o a o n e - p r o t o n m u l t i p l e t a t 6 5.92. The i r spectrum o f t h i s m a t e r i a l showed two a b s o r p t i o n bands a t 1672 and 1622 cm ^ due t o the a , 3 - u n s a t u r a t e d ketone f u n c t i o n a l i t y . * Thus, the v i n y l l i t h i u m r e a g e n t 111 s e r v e s as an e f f i c i e n t 3 - a c y l v i n y l a n i o n e q u i v a l e n t . I n g e n e r a l , t h e p r e p a r a t i o n o f the e n o l s i l y l e t h e r s 108 and 110 from the c o r r e s p o n d i n g 3 - t r i a l k y l s t a n n y l enones 7_4 and 7_0 was c a r r i e d o u t i n h i g h y i e l d . These p r o d u c t s were q u i t e s t a b l e and, w i t h r e a s o n a b l e p r e c a u t i o n s (e.g. e x c l u s i o n o f a i r ) , t h e s e compounds c o u l d be s t o r e d i n a f r e e z e r f o r s e v e r a l months w i t h -o u t s u b s t a n t i a l d e c o m p o s i t i o n . The f o r m a t i o n o f the v i n y l l i t h i u m 0SiMe 2Bu t OSiM^Bu* 0SiMe 2Bu t SnBun3 ^ ^ ^ N S n M e 3 108 110 U 1 * Two o t h e r e n o l s i l y l e t h e r s (113 and 121) were a l s o smoothly c o n v e r t e d (THF, aq. HCI) i n t o the c o r r e s p o n d i n g enones. A l t h o u g h these l a t t e r compounds gave s a t i s f a c t o r y s p e c t r a l d a t a ( i r , ^H nmr) they were not f u l l y c h a r a c t e r -i z e d . reagent 111 from the enol s i l y l ethers 108 and 110 was a simple process. Furthermore, the v i n y l l i t h i u m reagent 111 reacted smoothly with various e l e c t r o p h i l i c reagents to produce the corresponding substituted enol s i l y l ethers 112 in good y i e l d . F i n a l l y , hydrolysis of enol s i l y l ether 114 afforded the corresponding enone 124 i n good y i e l d . IV Preparation of g-Trialkylstannyl Ketones and Esters With the successful formation of the 0-acylvinyl anion equivalent 111 accomplished, our attention turned to further investigating the synthetic u t i l i t y of the lithium phenylthio-(tr i a l k y l s t a n n y l ) cuprates 7_2 and 7_3, and the trimethylstannyl-copper reagent 9_4. As mentioned previously, i t has been PhS(Me3Sn)CuLi PhS(n-Bu3Sn)Cul_i Me3SnCu.|_iBr.SMe2 72 73 94 reported that tetrahydrofuran or tetrahydrofuran-ammonia solutions of t r i a l k y l s t a n n y l l i t h i u m reagents r e a d i l y undergo Michael-type additions to a,g-unsaturated ketones and esters to give, a f t e r protonation, the corresponding 0 - t r i a l k y l s t a n n y l compounds i n 24 excellent yxeld. Certain of these l a t t e r compounds have 24 proven to be very useful and v e r s a t i l e synthetic intermediates. ' 54 -Fo r example, r e a c t i o n o f 2 - c y c l o p e n t e n - l - o n e w i t h t r i m e t h y l -s t a n n y l l i t h i u m i n 2:1 t e t r a h y d r o f u r a n - a m m o n i a f o l l o w e d by a l k y l a t i o n o f the r e s u l t a n t e n o l a t e a n i o n 125 w i t h n - p e n t y l i o d i d e , a f f o r d e d the ketone 126 i n 90% y i e l d (eq. 4 0 ) . Treatment o f 126 w i t h m e t h y l l i t h i u m gave the a l c o h o l 127. O x i d a t i o n o f the t r i m e t h y l s t a n n y l m o i e t y w i t h C o l l i n s r e a g e n t ^ 1 a f f o r d e d the hydroxy c y c l o p e n t a n o n e 128. B a s i c d e h y d r a t i o n then gave dihydrojasmone 129 i n 71% o v e r a l l y i e l d from 126. 24 MegSnLi SnMeg 125 Q-CgH I^ > 126 MeLi (40) N ^ C ^ NaOH C5 H11 C"%2pyr C 5 H 11 SnMe 3 129 128 127 The c o n j u g a t e a d d i t i o n o f or g a n o c u p r a t e r e a g e n t s t o a,3-unsaturated ketones and e s t e r s i s a w e l l known p r o -28_3o c e s s . I n p a r t i c u l a r , the r e a c t i o n o f l i t h i u m p h e n y l t h i o ( a l k y l ) c u p r a t e s (PhS(R)CuLi) w i t h enones r e a d i l y 31 a f f o r d s t h e c o r r e s p o n d i n g 3 - a l k y l k e t o n e s i n h i g h y i e l d . ' Some a l k y l c o p p e r d e r i v a t i v e s (RCu) can a l s o undergo such 2 8 — 3 0 53 c o n j u g a t e a d d i t i o n s . ' T h e r e f o r e , i n vi e w o f t h e o b s e r v a t i o n s summarized above, i t was o f i n t e r e s t t o i n v e s t i g a t e whether o r n o t t h e t r i a l k y l s t a n n y l r e a g e n t s 7_2, 73, and 9_4 c o u l d be employed f o r t h e c o n j u g a t e a d d i t i o n o f the t r i a l k y l s t a n n y l group t o a,3-unsaturated c a r b o n y l systems. R e a c t i o n o f m e s i t y l o x i d e 13 0 w i t h 1.3 e q u i v a l e n t s of l i t h i u m p h e n y l t h i o ( t r i m e t h y l s t a n n y l ) c u p r a t e 7_2 i n t e t r a h y d r o f u r a n (-20°C, 15 min; room t e m p e r a t u r e , l h ) , f o l l o w e d by p r o t o n a t i o n and workup, gave the g - t r i a l k y l -24 s t a n n y l ketone 131 i n 76% y i e l d (eq. 4 1 ) . The s t r u c t u r e 1) PhS(Me3Sn)CuLi > > 72 > 0 > 0 2)MeOH 130 131 a s s i g n e d t o 131 was c o n f i r m e d by i t s s p e c t r a l d a t a . The i r spectrum o f t h i s m a t e r i a l i n d i c a t e d the p r e s e n c e o f a s a t u r a t e d ketone (1713 cm . A l s o p r e s e n t i n the i r spectrum o f 131 was an a b s o r p t i o n band a t 765 cm ^ w h i c h was a t t r i b u t e d t o the t r i m e t h y l s t a n n y l group. The "^H nmr spectrum o f t h i s m a t e r i a l e x h i b i t e d a n i n e - p r o t o n s i n g l e t a t 5-0.02 ( w i t h s a t e l l i t e s due t o t i n c o u p l i n g , Jg n_ H=50Hz) which was a t t r i b u t e d t o the t r i m e t h y l s t a n n y l p r o t o n s . * A s i x - p r o t o n s i n g l e t ( s a t e l l i t e s , J =61Hz) due t o the on—n two m e t h y l groups a d j a c e n t t o the t r i m e t h y l s t a n n y l m o i e t y appeared a t 61.06, w h i l e a two-proton s i n g l e t ( s a t e l l i t e s , J e =66Hz) due t o t h e a-keto methylene p r o t o n s appeared a t 6 2.49. A l s o p r e s e n t i n the H nmr spectrum o f 131 was a t h r e e - p r o t o n s i n g l e t a t 6 2.10 w h i c h was a t t r i b u t e d t o the a c e t y l m e t h y l group. R e a c t i o n o f m e s i t y l o x i d e 130 w i t h 1.3 e q u i v a l e n t s o f the t r i m e t h y l s t a n n y l c o p p e r r e a g e n t 94_ i n t e t r a h y d r o f u r a n (-48°C, 2h; -20°C, l h ; room t e m p e r a t u r e , l h ) gave a y e l l o w o i l . A g l c a n a l y s i s o f t h i s m a t e r i a l showed t h a t i t c o n t a i n e d o n l y t r a c e amounts (^1%) o f the ketone 131; h e x a m e t h y l d i t i n and m e s i t y l o x i d e 130 were the major components. The l a t t e r was r e c o v e r e d i n h i g h y i e l d (79%) by chromatography o f the m i x t u r e on s i l i c a g e l . * C h e m i c a l s h i f t s o f t r i m e t h y l s t a n n y l compounds a r e r e l a t i v e t o CHC1„. - 57 -Reaction of mesityl oxide 130 with 1.5 equivalents of the tri-n-butylstannylcuprate reagent 7_3 i n tetrahydrof uran (-78°C, l h ; -20°C, l h ; room temperature, lh) afforded the 54 ketone 132 i n 69% y i e l d (eq. 42). The structure of 132 was confirmed by i t s spectral data. The i r spectrum of 1) PhS(n-Bu 3Sn)CuLi 73 n-Bu 3Sn-0 > / (42) 2) MeOH 130 132 132 exhibited a strong absorption band at 1718 cm indicating the presence of a saturated ketone. The nmr spectrum of th i s material exhibited a six-proton s i n g l e t at 61.12 which was attributed to the two t e r t i a r y methyl groups. A two-proton s i n g l e t (with s a t e l l i t e s due to t i n coupling, J Q _ =60Hz) due to the methylene protons adjacent to the uD r l carbonyl group appeared at 6 2 . 52. Also present i n the "^H nmr spectrum of 132 was a three-proton s i n g l e t at 6 2.11 due to the acetyl methyl group. Similar transformations were carried out using a variety of a,3-unsaturated ketones and esters as s t a r t i n g materials. The r e s u l t s are summarized i n Table 5. Each of the reaction products exhibited spectral data i n f u l l accord with the - 58 -assigned structure, and gave sa t i s f a c t o r y elemental analysis and/or molecular weight determination (high resolution mass spectrometry). In connection with the data summarized i n Table 5, the following points should be noted. In terms of i t s a b i l i t y to transfer conjugately the trimethylstannyl group to a,0-unsaturated carbonyl systems, the trimethylstannyl-cuprate reagent 7_2 was found to be more selec t i v e than trimethylstannyllithium. Thus, the data i n the Table show that although 7_2_ readi l y transferred the trimethylstannyl group to mesityl oxide 130, 2-cyclohexen-l-one 68_, isophorone 133, and methyl (E)-2-butenoate 134, i t f a i l e d to react with ethyl 3-methyl-2-butenoate 140 or with the B,B-disubstituted esters 141 and 142. On the other hand, trimethylstannyllithium smoothly converted a l l these substrates into the corresponding trimethylstannyl derivatives (entries 1,3,5,7,9,10, and 11, Table 5). The tri-n-butylstannylcuprate PhS (n-Bu^Sn) CuLi 7_3 also rea d i l y converted mesityl oxide 130, 2-cyclohexen-l-one 68, isophorone 133, and methyl (E)-2-butenoate 134 into the corresponding t r i a l k y l s t a n n y l derivatives 132, 135, 137, and 139 (entries 2,4,6, and 8, Table 5). In view of the obser-vations c i t e d above the reaction of 73_ with the B , B-disubstituted-a, B-unsaturated esters 14 0-142 was not attempted. From the res u l t s summarized i n Table 5 i t i s clear that the trimethylstannylcopper reagent 9_4 i s r e l a t i v e l y unreactive - 59 -140 141 142 Table 5. R e a c t i o n o f V a r i o u s T r i a l k y l s t a n n y l Reagents w i t h a , 3 - U n s a t u r a t e d Ketones and E s t e r s Y i e l d (%) ( R e a c t i o n C o n d i t i o n s ) Sntry S u b s t r a t e P r o d u c t M e 3 S n L i PhS(Me 3Sn)CuLi Me 3SnCu PhS(n-Bu 3 • L i B r - S M e 2 72 94 73 1 130 131 9 3 c 76(B) t r a c e ( E ) d 2 130 132 69 (F) 3 68 69 9 6 c 91(C) 32 ( E ) e 4 68 135 78 (F) 5 133 136 7 7 C 69(C) - ( E ) d 6 133 137 64 (F) 7 134 138 71(A) 67 (D) t r a c e (E) 8 134 139 74 (G) 9 140 143 74(A) " ( B ) d f _ f 10 141 144 8 0 C " ( B ) d f f 11 142 145 75 (A) " ( B ) d f f o - 61 -a d e f Y i e l d s from the p r e s e n t work r e f e r t o i s o l a t e d , p u r i f i e d m a t e r i a l . A l l r e a c t i o n s from the p r e s e n t work were c a r r i e d o u t i n t e t r a h y d r o f u r a n . R e a c t i o n c o n d i t i o n A: 1.1 e q u i v . o f Me^SnLi; -78°C, 15 min. A l l r e a c t i o n s employing PhS(Me^Sn)CuLi were c a r r i e d o u t a t -20°C, 15 min; room temp e r a t u r e l h . R e a c t i o n c o n d i t i o n B: 1.3 e q u i v . PhS(Me^Sn)CuLi; C: 2.0 e q u i v . ; D: 1.1 e q u i v a l e n t . R e a c t i o n c o n d i t i o n E: 1.3 e q u i v . Me^Sn•LiBr•SMe 2, -48°C, 2h; -20°C, l h ; room t e m p e r a t u r e , l h . A l l r e a c t i o n s employing PhS(n-Bu^Sn)CuLi were c a r r i e d o u t a t -78°C, l h ; -20°C, l h ; room t e m p e r a t u r e , l h . R e a c t i o n c o n d i t i o n F: 1.5 e q u i v . P h S ( n - B u 3 S n ) C u L i ; G: 1.3 e q u i v a l e n t . Taken from r e f . 24. S t a r t i n g m a t e r i a l r e c o v e r e d i n h i g h y i e l d . The d i k e t o n e 146 (48% y i e l d ) was a l s o formed i n t h i s r e a c t i o n . See t e x t . Not a t t e m p t e d . towards a , B - u n s a t u r a t e d c a r b o n y l compounds. In f a c t , the o n l y s u b s t r a t e t o w h i c h the copper r e a g e n t 9_4 e f f e c t i v e l y t r a n s f e r r e d the t r i m e t h y l s t a n n y l group was 2 - c y c l o h e x e n - l - o n e 68 ( e n t r y 3, Table 5 ) . However, t h i s r e a c t i o n gave i n a d d i t i o n t o the d e s i r e d ketone 6_9 a c o n s i d e r a b l e amount (48% y i e l d ) o f the d i k e t o n e 146 (eq. 4 3 ) . The s t r u c t u r e a s s i g n e d t o 146 was c o n f i r m e d by i t s s p e c t r a l d a t a . The (43) 68 69 146 i r spectrum o f t h i s compound e x h i b i t e d an i n t e n s e ketone a b s o r p t i o n a t 1705 cm 1 . The "*"H nmr spectrum o f 146 showed a n i n e - p r o t o n s i n g l e t a t 6 0.04 ( w i t h s a t e l l i t e s due t o t i n c o u p l i n g , Jg n_ H=50Hz) a r i s i n g from the t r i m e t h y l s t a n n y l p r o t o n s . A s e v e n - p r o t o n m u l t i p l e t c e n t e r e d a t 6 2.40 was a t t r i b u t e d t o the a - k e t o methine and methylene p r o t o n s . The s t e r e o c h e m i c a l i d e n t i t y o f t h i s m a t e r i a l was not d e t e r m i n e d . We have a l s o i n v e s t i g a t e d the r e a c t i o n s o f t r i m e t h y l -s t a n n y l l i t h i u m and l i t h i u m p h e n y l t h i o ( t r i m e t h y l s t a n n y l ) c u p r a t e - 63 -72 with methyl v i n y l ketone and ethyl acrylate. Some of the resul t s we have obtained are summarized i n Table 6. Each of the reaction products exhibited spectral data i n f u l l accord with the assigned structure, and gave a sa t i s f a c t o r y elemental analysis. N/^ Sn V R 147 R=Me 149 R=C02Et MegSn 148 R=Me 150 R=C02Et In connection with the data summarized i n Table 6, the following points should be noted. Although the reactions of trimethylstannyllithium and the cuprate reagent 7_2 with methyl v i n y l ketone resulted i n the formation of moderate amounts of 55 . . . the ketone 147, these transformations gave, in addition to the desired product, a substantial amount of the diketone 148 (entries 1 and 2, Table 6). S i m i l a r l y , the reaction of trimethylstannyllithium with ethyl acrylate in tetrahydrofuran afforded the ester 149^ and the diester 150 (entry 3, Table 6). Reaction of the cuprate reagent 72 with ethyl acrylate - 64 -gave on l y a low y i e l d of the d i e s t e r 150 (entry 4, Table 6). The formation of the d i c a r b o n y l compounds 148 and 150 (as w e l l as t h a t of the diketone 146, d e s c r i b e d e a r l i e r ) can be r a t i o n a l i z e d as f o l l o w s . Michael-type a d d i t i o n of the i n i t i a l l y formed e n o l a t e s p e c i e s 151 to a molecule of unreacted s u b s t r a t e would a f f o r d the en o l a t e 152. P r o t o n a t i o n of 152 would then g i v e the corresponding d i c a r b o n y l compound (Scheme 3). OLi 151 152 H + H + V V R 148 R=Me 147 R=Me 150 R=0Et : 149 R=OEt Scheme 3 - 65 -Tab l e 6. R e a c t i o n o f M e 3 S n L i and PhS (Me 3Sn) C u L i 7_2 w i t h M e t h y l V i n y l Ketone and E t h y l A c r y l a t e R e a c t i o n E n t r y S u b s t r a t e C o n d i t i o n s P r o d u c t s (% y i e l d ) 1 m e t h y l v i n y l ketone A 147 (43) + 148 (31) 2 •I II II B 147 (27) + 148 (37) 3 e t h y l a c r y l a t e A 149 (20) + 150 (29) 4 II II B 149 ( t r a c e ) + 150 (18) 5 me t h y l v i n y l ketone C 147 (77) + 148 ( t r a c e ) 6 e t h y l a c r y l a t e D 149 (70) + 150 ( t r a c e ) I n each case the s u b s t r a t e was added t o a t e t r a h y d r o f u r a n s o l u t i o n o f the t r i a l k y l s t a n n y l r e a g e n t . A l l r e a c t i o n s e m p l o y i n g PhS (Me 3Sn) C u L i 7_2 were c a r r i e d o u t a t -78°C, 30 min; -2 0°C, l h ; room t e m p e r a t u r e , 3 0 min. R e a c t i o n c o n d i t i o n A: 1.0 e q u i v . M e 3 S n L i ; -7 8°C, l h ; B: 1.3 e q u i v . P h S ( M e 3 S n ) C u L i 72 ; C: 1.3 e q u i v . P h S ( M e 3 S n ) C u L i 72 + 1.3 e q u i v . HOAc; D: 4.0 e q u i v . PhS ( M e 3 S n ) C u L i 7_2 + 2.0 e q u i v . HOAc. Y i e l d s r e f e r t o i s o l a t e d p u r i f i e d p r o d u c t s . - 66 -We have found however, t h a t the i n c l u s i o n o f a c e t i c a c i d i n the r e a c t i o n m i x t u r e s e mploying PhS (Me^Sn) C u L i 7_2_ g r e a t l y i n c r e a s e d the e f f i c i e n c y o f th e s e c o n v e r s i o n s . ^ F o r example, t r e a t m e n t o f a c o l d (-78°C) t e t r a h y d r o f u r a n s o l u t i o n o f 7_2 (1.3 e q u i v a l e n t s ) w i t h a t e t r a h y d r o f u r a n s o l u t i o n o f m e t h y l v i n y l ketone which c o n t a i n e d a c e t i c a c i d (1.3 e q u i v a l e n t s ) a f f o r d e d the ketone 147 i n 77% y i e l d . A s m a l l amount (^1%) of the d i k e t o n e 148 was a l s o i s o l a t e d ( e n t r y 5, Table 6 ) . * Presumably, the a d d i t i o n o f the t r i m e t h y l s t a n n y l group t o me t h y l v i n y l ketone and the p r o t o n a t i o n o f the r e s u l t a n t e n o l a t e s p e c i e s 151 (R=Me) w i t h , a c e t i c a c i d a r e r e l a t i v e l y f a s t compared w i t h the p r o t o n a t i o n o f the c u p r a t e r e a g e n t 72 and w i t h the f o r m a t i o n o f the d i m e r i c s p e c i e s 152 (R=Me). S i m i l a r l y , t r e a t m e n t o f a c o l d (-78°C) t e t r a h y d r o f u r a n s o l -u t i o n o f PhS (Me^Sn) C u L i 7_2 (4 e q u i v a l e n t s ) w i t h a m i x t u r e o f e t h y l a c r y l a t e and a c e t i c a c i d (2.0 e q u i v a l e n t s ) i n t e t r a h y d r o f u r a n a f f o r d e d the e s t e r 149 i n 70% y i e l d ( e n t r y 6, Table 6 ) . In g e n e r a l , the t r i a l k y l s t a n n y l c u p r a t e r e a g e n t s PhS (Me 3Sn ) C u L i 7_2 and PhS (n-Bu 3Sn ) C u L i 7_3 smoothly c o n v e r t e d m e s i t y l o x i d e 130, 2 - c y c l o h e x e n - l - o n e 6_8_, i s o p h o r o n e 133, and m e t h y l (E)-2-butenoate 134 i n t o t h e i r c o r r e s p o n d i n g 8 - t r i a l k y s t a n n y l d e r i v a t i v e s . These c o n v e r s i o n s were c l e a n and proceeded i n good y i e l d . The t r i m e t h y l s t a n n y l c u p r a t e * The i n c l u s i o n o f a c e t i c a c i d i n the r e a c t i o n m i x t u r e employ-i n g M e 3 S n L i r e s u l t e d i n a v e r y low y i e l d o f the ketone 147. - 67 -r e a g e n t 7_2 was found t o be more s e l e c t i v e than t r i m e t h y l -s t a n n y l l i t h i u m , s i n c e t h e former f a i l e d t o r e a c t w i t h 3 , g - d i s u b s t i t u t e d e s t e r s . I t was a l s o found t h a t v e r y r e a c t i v e a , g - u n s a t u r a t e d c a r b o n y l compounds (e.g., m e t h y l v i n y l ketone and e t h y l a c r y l a t e ) c o u l d be e f f i c i e n t l y c o n v e r t e d i n t o t h e i r 3 - t r i m e t h y l s t a n n y l d e r i v a t i v e s by t r e a t m e n t w i t h PhS (Me^Sn) C u L i 72_ i n the p r e s e n c e o f a c e t i c a c i d . F i n a l l y , the t r i m e t h y l s t a n n y l c o p p e r r e a g e n t 94_ e x h i b i t e d poor r e a c t i v i t y towards a , 3 - u n s a t u r a t e d c a r b o n y l compounds. V P r e p a r a t i o n o f g - T r i a l k y l s t a r i n y l - c t , g - u n s a t u r a t e d E s t e r s R e c e n t l y , i t has been shown t h a t o r g a n o c u p r a t e r e a g e n t s r e a d i l y undergo c o n j u g a t e a d d i t i o n r e a c t i o n s t o a , g - a c e t y l e n i c 58 5 9 e s t e r s . ' The s t e r e o c h e m i s t r y o f the r e s u l t a n t g - s u b s t i t u t e d - a , g - u n s a t u r a t e d e s t e r s was r e p o r t e d t o be h i g h l y dependent upon the r e a c t i o n t emperature and t h e n a t u r e o f t h e r e a c t i o n s o l v e n t . For example, r e a c t i o n o f m e t h y l 2 - o c t y n o a t e w i t h l i t h i u m d i m e t h y l c u p r a t e i n t e t r a h y d r o f u r a n a t -78°C f o r 3h a f f o r d e d the e s t e r s 153 and 154 i n a r a t i o o f 99.8:0.2, r e s p e c t i v e l y (eq. 4 4 ) . However when the r e a c t i o n was c a r r i e d out i n t e t r a h y d r o f u r a n - e t h e r a t 0°C f o r %5 min, the e s t e r s 153 and 5 8 154 were formed i n a r a t i o o f 39:61, r e s p e c t i v e l y . Thus, i t was o f i n t e r e s t t o i n v e s t i g a t e whether o r n o t t h e c u p r a t e r e a g e n t s PhS (Me 3S n) C u L i 72 and PhS (n-Bu 3Sn) C u L i 7_3 c o u l d be used f o r the c o n v e r s i o n o f a , g - a c e t y l e n i c e s t e r s i n t o the - 68 -n-C5H11C=CC02Me Me2CuLi (A4) n-CbH}] p H-C5H1lv C02Me Me C02Me Me 154 153 c o r r e s p o n d i n g 3 - t r i a l k y l s t a n n y l - a , 3 - u n s a t u r a t e d e s t e r s . R e a c t i o n o f e t h y l 2-pentynoate 155 w i t h 1.3 e q u i v a l e n t s o f l i t h i u m p h e n y l t h i o ( t r i m e t h y l s t a n n y l ) c u p r a t e 7_2 i n t e t r a -h y d r o f u r a n a t -78°C f o r 3h f o l l o w e d by p r o t o n a t i o n and workup a f f o r d e d a c o l o r l e s s o i l (69%) . A g l c a n a l y s i s o f t h i s m a t e r i a l showed t h a t i t was composed o f a m i x t u r e o f the ( E ) - and ( Z ) - 3 - t r i m e t h y l s t a n n y l e s t e r s 156 and 157 i n a r a t i o o f 68:32, r e s p e c t i v e l y (eq. 4 5 ) . An a n a l y t i c a l EtC=CC02Et 155 1) PhS(Me3Sn)CuLi II 2) MeOH -> Me3Sn H M e 3 S n £ 0 2 E t Et C02Et Et H 156 (45) 157 - 69 -sample o f each o f the s e p r o d u c t s was o b t a i n e d by p r e p a r a t i v e t i c . The s t r u c t u r e s a s s i g n e d t o 156 and 157 were s u p p o r t e d by t h e i r s p e c t r a l d a t a . The uv spectrum o f t h e (E)-isomer 156 e x h i b i t e d a s t r o n g a b s o r p t i o n a t 220 nm, w i t h £=13,800 ( TT—»TT* t r a n s i t i o n o f ct, B - u n s a t u r a t e d e s t e r ) . Two a b s o r p t i o n bands a t 1715 and 1598 cm i n the i r spectrum o f t h i s compound a l s o i n d i c a t e d the p r e s e n c e o f an a, B - u n s a t u r a t e d e s t e r . The "^H nmr spectrum e x h i b i t e d a n i n e - p r o t o n s i n g l e t a t 6 0.12 ( w i t h s a t e l l i t e peaks due t o t i n c o u p l i n g , J =54Hz) which was fan — H d e r i v e d from the t r i m e t h y l s t a n n y l p r o t o n s . A broad two-p r o t o n q u a r t e t (J^8Hz) due t o the a l l y l i c methylene p r o t o n s appeared a t 6 2.85 . A l s o p r e s e n t i n t h e "^H nmr spectrum o f 156 was a on e - p r o t o n t r i p l e t (J^2Hz) a t 66.91 ( s a t e l l i t e peaks J _ =73Hz) whi c h was a t t r i b u t e d t o the v i n y l p r o t o n . Sn-H The uv spectrum o f the (Z_)-isomer 157 e x h i b i t e d a s t r o n g a b s o r p t i o n a t 218 nm, w i t h £ = 9,300 ( TT->TT* o f a,B-u n s a t u r a t e d e s t e r ) . The i r spectrum o f t h i s m a t e r i a l a l s o i n d i c a t e d the presence o f an a , B - u n s a t u r a t e d e s t e r (1701 and 1601 cm "*") . In the "^ H nmr spectrum o f 157 the t r i m e t h y l -s t a n n y l p r o t o n s gave r i s e t o a n i n e - p r o t o n s i n g l e t a t 6 0.12 ( w i t h s a t e l l i t e peaks due t o t i n c o u p l i n g , J S n _ H = 5 4 H z ) . The a l l y l i c methylene p r o t o n s gave r i s e t o a broad two-p r o t o n q u a r t e t (J^8Hz) a t 62.41, w h i l e the o l e f i n i c p r o t o n - 70 -gave r i s e t o a one - p r o t o n t r i p l e t (Jo,2Hz) a t 66. 34 ( s a t e l l i t e p eaks, J„ =12lHz). S n - H Thus, the "^"H nmr o f t h e s e p r o d u c t s f u l l y c o r r o b o r a t e d the s t e r e o c h e m i c a l a s s i g n m e n t s . F o r example, the a l l y l i c methylene p r o t o n s o f the (E)-isomer 156 ( e t h y l group c i s to the C 0 2 E t group) gave r i s e t o a broad q u a r t e t (J^8Hz) a t 6 2.85. The c o r r e s p o n d i n g s i g n a l d e r i v e d from t h e (Z^-isomer 157 ( e t h y l group and C 0 2 E t i n a t r a n s r e l a t i o n s h i p ) was found, as e x p e c t e d , a t h i g h e r f i e l d (62.41, q, J^8Hz). A l s o , the magnitude o f the observ e d Sn -H c o u p l i n g c o n s t a n t (J„ „) o f t h e o l e f i n i c p r o t o n o f t h e (E ) - i s o m e r 156 (Me^Sn c i s t o the o l e f i n i c p r o t o n ) was 73Hz, which was about o n e - h a l f t h a t found f o r t h e c o r r e s p o n d i n g p r o t o n o f t h e (Z)-isomer 157 (Me^Sn t r a n s t o the o l e f i n i c p r o t o n , Ja = 1 2 l H z ) . — j i n — r i 34 T h i s i s c o n s i s t e n t w i t h t h e f i n d i n g s o f p r e v i o u s w o r k e r s . When e t h y l 2-pentynoate 155 was a l l o w e d t o r e a c t w i t h 2.5 e q u i v a l e n t s o f PhS (Me^Sn) C u L i 7_2 i n t e t r a h y d r o f uran a t -100°C f o r 6h and the r e s u l t a n t s o l u t i o n was t r e a t e d w i t h m e t h a n o l , t h e two g e o m e t r i c isome r s 156 and 157 were o b t a i n e d (81%) i n a r a t i o o f 97:3. However, the r e a c t i o n c o u l d be c a r r i e d o u t i n a s h o r t e r time and w i t h an even h i g h e r s t e r e o s e l e c t i v i t y by a d d i n g a t e t r a h y d r o f u r a n s o l u t i o n o f e t h y l 2-pentynoate c o n t a i n i n g 1.7 e q u i v a l e n t s o f methanol t o a s o l u t i o n (THF) o f 2.0 e q u i v a l e n t s o f the c u p r a t e r e a g e n t 72 (-100°C, 15 min; -78°C, 3 h ) . Under th e s e c o n d i t i o n s the c o n j u g a t e a d d i t i o n p r o d u c t c o n s i s t e d o f e s s e n t i a l l y pure - 71 -(E)-isomer 156 (79% y i e l d , <1% 157). The s p e c t r a l p r o p e r t i e s of t h i s m a t e r i a l were i d e n t i c a l w i t h t h o s e o f the same mat-e r i a l r e p o r t e d e a r l i e r . On the o t h e r hand, r e a c t i o n o f e t h y l 2-pentynoate 155 w i t h 1.2 e q u i v a l e n t s o f PhS (Me^Sn) C u L i 7_2 a t -78°C f o r 15 min and a t ^-48°C f o r 4h, f o l l o w e d by p r o t o n a t i o n (MeOH) and workup, a f f o r d e d (76%) the two isomers 156 and 157 i n a r a t i o o f 2:98, r e s p e c t i v e l y . The s p e c t r a l p r o p e r t i e s o f t h i s m a t e r i a l were e s s e n t i a l l y i d e n t i c a l w i t h t h o s e o f the (Z,)-isomer 157 r e p o r t e d e a r l i e r . I t i s c l e a r from the above r e s u l t s t h a t the ( E ) -isomer 156 i s the p r o d u c t o f k i n e t i c c o n t r o l , w h i l e the (Z)- i s o m e r 157 i s produced under t h e r m o d y n a m i c a l l y c o n t r o l l e d c o n d i t i o n s . A p p a r e n t l y , a t low t e m p e r a t u r e s (e.g., -100°C) the " k i n e t i c " i n t e r m e d i a t e ( c f . 158)* i s r e a s o n a b l y s t a b l e and i s o m e r i z e s o n l y v e r y s l o w l y . A t somewhat h i g h e r * We do not i n t e n d t o i m p l y a c t u a l s t r u c t u r e s by t h e s e f o r m u l a s ( c f . 158), b u t use them m a i n l y f o r the sake o f c o n v e n i e n c e . t e m p e r a t u r e s (e.g., -78°C) i s o m e r i z a t i o n o f 158 i n t o 159 does o c c u r , b u t t h i s t r a n s f o r m a t i o n can be m i n i m i z e d by the p r e s e n c e o f a p r o t o n s o u r c e such as methanol ( p r o t o n a t i o n o f 158 f a s t e r than i s o m e r i z a t i o n ) . I f the r e a c t i o n m i x t u r e MeoSn CuSPh MeoSn COoEt H — H Et C02Et Et CuSPh U 158 159 i s a l l o w e d t o warm t o -48 UC i n the absence o f m ethanol, e q u i l i b r a t i o n (158 ^ 1 5 9 ) t a k e s p l a c e , w i t h the e q u i l i b r i u m l a r g e l y f a v o r i n g i n t e r m e d i a t e 159. Subsequent p r o t o n a t i o n r e s u l t s i n the f o r m a t i o n o f n e a r l y pure (Z_)-isomer 157. These o b s e r v a t i o n s p a r a l l e l t o some e x t e n t t h o s e made f o r t h e r e a c t i o n o f l i t h i u m d i a l k y l c u p r a t e s w i t h a , B - a c e t y l e n i c e s t e r s . ^ 8 , 5 9 However i n the l a t t e r t r a n s f o r m a t i o n s , the " t h e r m o d y n a m i c a l l y c o n t r o l l e d " r e a c t i o n s d i d n o t l e a d t o h i g h s t e r e o s e l e c t i v i t y . S i m i l a r t r a n s f o r m a t i o n s were c a r r i e d o u t u s i n g the a , 3 - a c e t y l e n i c e s t e r s 160-162. The r e s u l t s a r e summarized i n T able 7. Each of the r e a c t i o n p r o d u c t s e x h i b i t e d s p e c t r a l d a t a i n f u l l a c c o r d w i t h the a s s i g n e d s t r u c t u r e , and gave a s a t i s f a c t o r y e l e m e n t a l a n a l y s i s and/or a m o l e c u l a r w e i g h t d e t e r m i n a t i o n ( h i g h r e s o l u t i o n mass s p e c t r o m e t r y ) . * PhS(Me3Sn)CuLi 72 RC=CCO 2 R' > 155 160 161 162 MeoSn H MeoSn C09R' H + H R COoR' R H R 3f5 6 163 164 165 157 166 167 168 155 156 157 R=Et, R=Et 160 163 166 R=Me, R=Et 161 164 167 R=Me 2 tBuSiOCH 2CH 2, R=Me 162 165 168 R=t-Bu, R=Et In c o n n e c t i o n w i t h t h e d a t a t a b u l a t e d i n Table 7, t h e f o l l o w i n g p o i n t s s h o u l d be n o t e d . The t r i m e t h y l s t a n n y l c u p r a t e r e a g e n t 7_2 r e a d i l y r e a c t e d w i t h the a, g - a c e t y l e n i c e s t e r s and depending on e x p e r i m e n t a l c o n d i t i o n s gave, h i g h l y s t e r e o s e l e c t i v e l y , e i t h e r t he (E) - o r the ( Z ) - g - t r i m e t h y l -s t a n n y l - a , 3 - u n s a t u r a t e d e s t e r s . F o r example, r e a c t i o n o f the a , B - a c e t y l e n i c e s t e r s 155, 160, and 161 w i t h the c u p r a t e * J?he mass s p e c t r a o f the B-Me^Sn e s t e r s l i s t e d i n Ta b l e 7 f a i l e d t o show m o l e c u l a r i o n peaks = M + ) . However, the mass s p e c t r a o f a l l t h e s e compounds c o n s i s t e n t l y e x h i b i t e d M+-Me peaks. T h i s i s c o n s i s t e n t w i t h p r e v i o u s s t u d i e s c o n c e r n i n g t h e f r a g m e n t a t i o n o f the m o l e c u l a r i o n s o f o r g a n o t i n compounds.60 T h e r e f o r e , the m o l e c u l a r w e i g h t d e t e r m i n a t i o n s o f the compounds l i s t e d i n T a b l e 7 were c a r r i e d o u t on the M+-Me fragment. - 74 -Tab l e 7. P r e p a r a t i o n o f 8 - T r i m e t h y l s t a n n y l - a , g - u n s a t u r a t e d E s t e r s E n t r y S u b s t r a t e R e a c t i o n a C o n d i t i o n P r o d u c t s ( R a t i o ) b (% Y i e l d ) 0 1 155 A 156 + 157 (^99:1) (79) 2 155 B 156 + 157 ( 2:98) (76) 3 160 A 163 + 166 (^99:1) (78) 4 160 B 163 + 166 ( 2:98) (76) 5 161 A 164 + 167 ( 96:4) (82) 6 161 B 164 + 167 ( 4:96) (81) 7 162 C 165 + 168 ( 8:92) (84) 8 162 D 165 168 ( 2:98) (86) A l l r e a c t i o n s were c a r r i e d o u t i n t e t r a h y d r o f u r a n . R e a c t i o n c o n d i t i o n A: 2.0 e q u i v . PhS(Me^Sn)CuLi, 1.7 e q u i v . MeOH; -100°C, 15 min; -78°C, 3h; B: 1.2 e q u i v . P h S ( M e 3 S n ) C u L i ; -78°C, 15 min; -48°C, 4h; quenched w i t h MeOH; C: 3.0 e q u i v . P h S ( M e 3 S n ) C u L i , 1.7 e q u i v EtOH: -100°C, 15 min; -78°C, 6h; D: 1.4 e q u i v . P h S ( M e 3 S n ) C u L i ; -78°C, 15 min; -48°C, 4h. k The p r o d u c t r a t i o s were d e t e r m i n e d by g l c , employing a column ( 1/8 i n . x 6 f t ) packed w i t h 3% OV-17 on chromosorb W(HP) (80-100 mesh). C Y i e l d r e f e r s t o i s o l a t e d p u r i f i e d m i x t u r e s o f the s t e r e o i s o m e r s . - 75 -r e a g e n t 7_2 i n t h e pr e s e n c e o f meth a n o l * a f f o r d e d t h e ( E ) - t r i m e t h y l s t a n n y l e s t e r s 156, 163, and 164 r e s p e c t i v e l y (>96% s t e r e o s e l e c t i v i t y ) ( e n t r i e s 1,3, and 5, Table 7 ) . On the o t h e r hand, i f t h e s e r e a c t i o n m i x t u r e s were a l l o w e d t o warm t o -4 8°C i n the absence o f meth a n o l , subsequent p r o t o n a t i o n and workup gave the c o r r e s p o n d i n g ( Z _ ) - 0 - t r i m e t h y l -s t a n n y l e s t e r s 157, 166, and 167 (>96% s t e r e o s e l e c t i v i t y ) ( e n t r i e s 2,4, and 6, Table 7 ) . However, i t was found t h a t r e a c t i o n (-100°C, 15 min; -78°C, 6h) o f e t h y l 4 , 4 - d i m e t h y l - 2 - p e n t y n o a t e 162 w i t h PhS (Me 3Sn) C u L i 7_2 i n the pre s e n c e o f e t h a n o l * * g a v e (84%) a m i x t u r e o f the ( E ) - and ( Z ) - e s t e r s 165 and 168 i n a r a t i o o f 8:92, r e s p e c t i v e l y ( e n t r y 7, Table 7 ) . * The use o f e t h a n o l as the p r o t o n s o u r c e f o r the c o n v e r s i o n o f 160 i n t o 163 gave e q u i v a l e n t r e s u l t s . * When methanol was used as the p r o t o n s o u r c e t h i s c o n v e r s i o n gave, i n a d d i t i o n t o 165 and 168 (10:90), a moderate amount (^10%) o f the c o r r e s p o n d i n g m e t h y l e s t e r s . F u r t h e r m o r e , a c o n s i d e r a b l e e x c e s s (3.0 e q u i v a l e n t s ) o f 7_2 was r e q u i r e d t o e f f e c t complete c o n v e r s i o n o f the s t a r t i n g m a t e r i a l . A p p a r e n t l y , the s t e r i c a l l y b u l k y t e r t - b u t y l group not o n l y impeded c o n j u g a t e a d d i t i o n o f the c u p r a t e r e a g e n t t o t h i s a c e t y l e n i c e s t e r , b u t a l s o d e s t a b i l i z e d t h e " k i n e t i c " i n t e r m e d i a t e ( c f . 158) s u f f i c i e n t l y t o a l l o w i s o m e r i z a t i o n ( t o the "thermodynamic" i n t e r m e d i a t e , c f . 159) t o become f a s t e r than p r o t o n a t i o n . The use o f a c e t i c a c i d as the p r o t o n s o u r c e , i n the hope t h a t a s t r o n g e r a c i d might p r o t o n a t e the " k i n e t i c " i n t e r m e d i a t e ( c f . 158) more r e a d i l y than e t h a n o l , gave m o s t l y 168 as w e l l as a l a r g e amount of r e c o v e r e d s t a r t i n g m a t e r i a l . R e a c t i o n o f 162 w i t h the c u p r a t e r e a g e n t 7_2 a t -78°C f o r 15 min and a t -48°C f o r 4h a f f o r d e d the ( E ) - and ( Z ) - e s t e r s 165 and 168 i n a r a t i o o f 2:98, r e s p e c t i v e l y ( e n t r y 8, T a b l e 7 ) . I n i t i a l l y , we were concerned t h a t the major p r o d u c t i s o l a t e d from the c o n v e r s i o n s e mploying 162 as the s t a r t i n g m a t e r i a l m i g h t be t h e a-isomer 169. However, r e d u c t i o n o f the p r o d u c t o b t a i n e d the l a t t e r r e a c t i o n w i t h l i t h i u m 61 o ethoxyaluminum h y d r i d e i n e t h e r (0 C, 3 0 min; room t e m p e r a t u r e , l h ) a f f o r d e d (87%) the a l c o h o l 170. The s t r u c t u r e a s s i g n e d t o 170 was c o n f i r m e d by i t s s p e c t r a l d a t a . The i r spectrum of t h i s m a t e r i a l e x h i b i t e d an a l c o h o l a b s o r p t i o n a t 3310 cm 1 . I n the "'"H nmr spectrum - 77 -t-Bu SnMe3 Me3Sn pH o0H C0 2Et 169 170 two n i n e - p r o t o n s i n g l e t s a t 6 0.23 ( w i t h s a t e l l i t e peaks due t o t i n c o u p l i n g , J _ =52Hz) and 61.06 were a t t r i b u t e d t o an —ri the t r i m e t h y l s t a n n y l p r o t o n s and the t e r t - b u t y l p r o t o n s , r e s p e c t i v e l y . The methylene p r o t o n s of the hydroxymethylene m o i e t y appeared as a two-proton m u l t i p l e t a t 64.14. F i n a l l y , t h e o l e f i n i c p r o t o n gave r i s e t o a one - p r o t o n t r i p l e t (J=7Hz) a t 6 6.17 ( w i t h s a t e l l i t e peaks, J _ =148Hz) c l e a r l y b n ~ r l showing t h a t t h e a l c o h o l 170 p o s s e s s e s t h e s t r u c t u r e as shown.* I t s h o u l d a l s o be no t e d t h a t B - t r i a l k y l s t a n n y l e s t e r s have been p r e p a r e d p r e v i o u s l y by the h y d r o s t a n n y l a t i o n o f 34 63 64 a , 6 - a c e t y l e n i c e s t e r s . ' ' However t h e s e l a t t e r t r a n s -f o r m a t i o n s a r e not v e r y r e g i o s e l e c t i v e . F o r example, r e a c t i o n o f t r i m e t h y l t i n h y d r i d e w i t h e t h y l 2-butynoate 160 gave a m i x t u r e o f the a - t r i m e t h y l s t a n n y l e s t e r s 171 and 172 * C o u p l i n g c o n s t a n t s o f the type J a b a r e i n the o r d e r o f 4-10Hz, whereas c o u p l i n g c o n s t a n t s o f t h e type J^c u s u a l l y l i e w i t h i n the range o f 0.5-2.0Hz. 6 2 H c - C - H t as well as the B-trimethylstannyl ester 166 in a r a t i o of 64 59:9:32, respectively (eq. 4 6 ) . MeC=CC0 2Et + Me3SnH A > 160 Me. C0 2Et Me H H + H SnMe 3 Me3Sn 171 172 166 We have also investigated the reaction of the lithium phenylthio ( t r i a l k y l s t a n n y l ) cuprates 7_2 and 7_3 with ethyl solution of the trimethylstannyl cuprate 7_2 (1.1 equivalents) which contained 3.0 equivalents of ethanol with a solution (THF) of ethyl propiolate 173 gave, after workup, a yellow o i l . A glc analysis of th i s material showed that i t was composed of a mixture of the 0-trimethylstannyl 34 34 esters 174 and 175, along wxth what we believe to be 34 the a-trimethylstannyl ester 176 in a r a t i o of 90:3:7, respectively (eq. 4 7 ) . This l a t t e r component was not p u r i f i e d or f u l l y characterized i n th i s work, however, i t has been prepared previously by the hydrostannylation 34 of ethyl propiolate 173. P u r i f i c a t i o n of the mixture of propiolate 173. Treatment of a cold (-100°C) tetrahydrofuran - 79 -PhS(Me3Sn)CuLi 72 HC=CC0 2Et > 173 EtOH (47) H ,C02Et H SnMe 3 + H C0 2Et H H H COoEt 174 175 176 r e a c t i o n p r o d u c t s by means o f p r e p a r a t i v e t i c gave the ( E ) - g - t r i m e t h y l s t a n n y l - a , g - u n s a t u r a t e d e s t e r 174 i n 56% y i e l d . T h i s m a t e r i a l was c o n t a m i n a t e d w i t h a s m a l l amount o f the a - i s o m e r 176. The s t r u c t u r e o f 174 was c o n f i r m e d by i t s s p e c t r a l d a t a . The uv spectrum o f t h i s m a t e r i a l e x h i b i t e d a s t r o n g a b s o r p t i o n a t 215 nm, w i t h e = 11,800 (7T-»Tr* o f a, g - u n s a t u r a t e d e s t e r ) . Two a b s o r p t i o n s i n t h e i r spectrum a t 1720 and 1597 cm 1 a l s o i n d i c a t e d the p r e s e n c e o f an a , g - u n s a t u r a t e d e s t e r f u n c t i o n a l i t y . I n the "*"H nmr spectrum o f t h i s m a t e r i a l the t r i m e t h y l s t a n n y l p r o t o n s gave r i s e t o a n i n e - p r o t o n s i n g l e t a t 6 0.14 ( w i t h s a t e l l i t e peaks due t o t i n c o u p l i n g , J g n _ H = 5 4 H z ) . The a - o l e f i n i c p r o t o n o f 174 gave r i s e t o a o n e - p r o t o n d o u b l e t (J=19Hz) a t 66. 27 ( w i t h s a t e l l i t e p eaks, J., =63Hz) w h i l e bn —H the g - o l e f i n i c p r o t o n gave r i s e t o a o n e - p r o t o n d o u b l e t (J=19Hz) a t 67.73 ( s a t e l l i t e s , J„ =70Hz). A l s o p r e s e n t Sn-H ^ - 80 -i n t h e "*"H nmr spectrum o f t h i s m a t e r i a l were two (weak) d o u b l e t s (J^3Hz) a t 65.93 and 66.85. These were a t t r i b u t e d t o t h e 3 - o l e f i n i c p r o t o n s o f t h e s m a l l amount o f a-isomer 176 p r e s e n t . The 3 - t r i - n - b u t y l s t a n n y l e s t e r 177 was p r e p a r e d i n a s i m i l a r f a s h i o n . Treatment o f a c o l d (-100°C) t e t r a h y d r o f u r a n s o l u t i o n o f t h e t r i - n - b u t y l s t a n n y l c u p r a t e r e a g e n t 7_3 (1.1 e q u i v a l e n t s ) w h i c h c o n t a i n e d e t h a n o l (3.0 e q u i v a l e n t s ) w i t h a s o l u t i o n (THF) o f e t h y l p r o p i o l a t e 173 a f f o r d e d , a f t e r workup, a y e l l o w o i l . G l c and "*"H nmr a n a l y s e s i n d i c a t e d t h a t t h i s m a t e r i a l was composed m a i n l y o f t h e d e s i r e d e t h y l ( E ) - 3 - t r i - n - b u t y l s t a n n y l a c r y l a t e 177. A s m a l l amount o f t h e (Z^)-isomer 178 and what we b e l i e v e t o be t h e a-isomer 179 were a l s o p r e s e n t (eq. 4 8 ) . The l a t t e r compound was n o t p u r i f i e d o r f u l l y c h a r a c t e r i z e d . P u r i f i c a t i o n o f t h e crude p r o d u c t by p r e p -a r a t i v e t i c a f f o r d e d (59%) t h e 3 - 3 - t r i - n - b u t y l s t a n n y l e s t e r 177. The i d e n t i t y o f t h i s m a t e r i a l was c o n f i r m e d by i t s s p e c t r a l d a t a . The uv spectrum o f t h i s m a t e r i a l e x h i b i t e d an a b s o r -p t i o n a t 226 nm, w i t h e= 6,600. The i r s p e c t r u m o f 177 showed two a b s o r p t i o n bands a t 17 21 and 15 95 cm 1 w h i c h i n d i c a t e d t h e p r e s e n c e o f an u n s a t u r a t e d e s t e r . I n t h e "'"H nmr spectrum t h e a - o l e f i n i c p r o t o n gave r i s e t o a o n e - p r o t o n d o u b l e t (J=19Hz) a t 66.30 ( w i t h s a t e l l i t e peaks due t o t i n c o u p l i n g , J S n _ H = 5 4 H z ) . The 6 - o l e f i n i c p r o t o n gave r i s e t o a one-p r o t o n d o u b l e t ( J=19Hz) a t 67.76 ( s a t e l l i t e p eaks, J C t i _ u = 6 0 H Z ) . - 81 -PhS(n-Bu3Sn)CuLi 73 HC=CC02Et > 173 EtOH (48) H p02Et + H SnBcA H C02Et H H H COoEt 177 178 179 R e a c t i o n o f e t h y l p r o p i o l a t e 173 w i t h PhS(Me^Sn)CuLi 72 i n the absence o f a p r o t o n s o u r c e f a i l e d t o produce s y n t h e t i c a l l y u s e f u l y i e l d s o f the d e s i r e d 8 - t r i a l k y l s t a n n y l e s t e r s . Presumably, the r e l a t i v e l y a c i d i c p r o t o n o f the t e r m i n a l a c e t y l e n e m o i e t y i n t e r f e r e d w i t h t h i s c o n v e r s i o n . T h e r e f o r e , a n o t h e r means f o r p r e p a r i n g the (Z_)-esters 17 5 and 178 was sought. P r e v i o u s work d e s c r i b e d i n t h i s t h e s i s had shown t h a t t h e t r i m e t h y l s t a n n y l c o p p e r r e a g e n t 9_4 (Me^SnCu*LiBr•SMe2) i s a r e l a t i v e l y m i l d r e a g e n t f o r the c o n v e r s i o n o f 8-iodo enones i n t o t h e i r c o r r e s p o n d i n g 3 - t r i m e t h y l s t a n n y l d e r i v a t i v e s . T h e r e f o r e , i t was hoped t h a t t h i s r e a g e n t would e f f i c i e n t l y c o n v e r t t he ( Z ) - 3 - t o s y l o x y e s t e r 180* i n t o the c o r r e s p o n d i n g * I would l i k e t o thank Dr. G. S. Bates and Mr. S. Ramaswamy f o r a generous sample o f t h i s compound. The 3 - t o s y l o x y e s t e r 180 can be p r e p a r e d by t r a p p i n g t h e sodium e n o l a t e o f e t h y l 3-oxypropanoate65 w i t h p - t o l u e n e s u l f o n y l c h l o r i d e i n THF (0°C t o room t e m p e r a t u r e , ^ 2 h ) . - 82 -(Z^ - 3 - t r i m e t h y l s t a n n y l e s t e r 17 5. T h i s was ind e e d found t o be the c a s e . R e a c t i o n o f e t h y l ( Z ) - 3 - t o s y l o x y a c r y l a t e 180 w i t h 1.3 e q u i v a l e n t s o f the copper r e a g e n t 9_4 i n t e t r a h y d r o f u r an (-48°C, 2h; -20°C, l h ; room t e m p e r a t u r e , l h ) a f f o r d e d a y e l l o w o i l . A g l c a n a l y s i s o f t h i s m a t e r i a l showed t h a t 34 i t was composed o f the (E) - and (Z) - e s t e r s 174 and 34 175 i n a r a t i o o f 3:97, r e s p e c t i v e l y (eq. 4 9 ) . Other minor u n i d e n t i f i e d p r o d u c t s were a l s o p r e s e n t . P u r i f i c a t i o n o f the crude m i x t u r e by p r e p a r a t i v e t i c a f f o r d e d pure e t h y l ( Z ) - 3 - t r i m e t h y l s t a n n y l a c r y l a t e 17 5 i n 61% y i e l d . TsO N / H Me3SnCu-LiBr.SMe2 /C02Et 94 M e 3 S n -> H + 174 (49) 180 H H 175 The s t r u c t u r e a s s i g n e d t o 17 5 was s u p p o r t e d by i t s s p e c t r a l d a t a . The uv spectrum o f t h i s compound e x h i b i t e d a s h o u l d e r a t 214 nm, w i t h e= 6,900. The i r spectrum o f t h i s compound showed two bands a t 1710 and 1590 cm 1 w h i c h i n d i c a t e d t h e p r e s e n c e o f an a , 3 - u n s a t u r a t e d e s t e r . I n t h e - 83 -"*"H nmr spectrum o f 17 5 the t r i m e t h y l s t a n n y l p r o t o n s gave r i s e t o a n i n e - p r o t o n s i n g l e t a t 60.19 ( w i t h s a t e l l i t e peaks due t o t i n c o u p l i n g , J =55Hz). A on e - p r o t o n d o u b l e t ( w i t h s a t e l l i t e p eaks, J„ =124Hz) due t o the c Sn-H a - o l e f i n i c p r o t o n appeared a t 66.72 (J=12Hz), w h i l e a second o n e - p r o t o n d o u b l e t ( s a t e l l i t e peaks, J^, =68Hz) c Sn-H due t o the B - o l e f i n i c p r o t o n appeared a t 67.17 (J=12Hz). S i m i l a r l y , r e a c t i o n o f e t h y l ( Z ) - 3 - t o s y l o x y a c r y l a t e 180 w i t h 1.2 e q u i v a l e n t s o f the t r i - n - b u t y l s t a n n y l c o p p e r r e a g e n t 181* i n 5:1 t e t r a h y d r o f u r a n - h e x a m e t h y l p h o s p h o r a m i d e * * (-48°C, 2h; -20°C, l h ) gave, a f t e r workup and p r e p a r a t i v e t i c , e t h y l ( Z _ ) - 3 - t r i - n - b u t y l s t a n n y l a c r y l a t e 178 i n 63% y i e l d (eq. 5 0 ) . The i d e n t i t y o f t h i s m a t e r i a l was c o n f i r m e d TsO N / H C0 2Et H n-B^SnCu-LiBr-SN/^ 181 > Q-Bu3Sn pc^Et (50) 180 H H 178 * P r e p a r e d by r e a c t i o n o f n - B u 3 S n L i w i t h Me 2SCuBr i n t e t r a h y d r o f u r a n a t -48°C. ** When t h i s r e a c t i o n was c a r r i e d o u t i n the absence o f HMPA a s l i g h t l y lower y i e l d o f 178 was r e a l i z e d . - 84 -by i t s s p e c t r a l d a t a . The uv spectrum o f 178 e x h i b i t e d an a b s o r p t i o n a t 228 nm, w i t h e= 3,500. Two a b s o r p t i o n bands i n the i r spectrum a t 1697 and 1577 cm 1 c o n f i r m e d the p r e s e n c e o f an a , 3 - u n s a t u r a t e d e s t e r . The nmr spectrum o f compound e x h i b i t e d two o n e - p r o t o n d o u b l e t s (both J=13Hz) a t 6 6.74 ( w i t h s a t e l l i t e peaks due t o t i n c o u p l i n g , J e =110Hz) and a t 67.15 ( w i t h s a t e l l i t e p e a ks, J_, =61Hz). on—ti o n - r i These were a t t r i b u t e d t o the a - o l e f i n i c and 0 - o l e f i n i c p r o t o n s , r e s p e c t i v e l y . A l t h o u g h s e v e r a l 3 - t r i a l k y l s t a n n y l - a , 3 - u n s a t u r a t e d e s t e r s have been p r e p a r e d p r e v i o u s l y , the uv s p e c t r a o f t h e s e 34 compounds have n o t been r e p o r t e d . Some of the r e s u l t s we have o b t a i n e d a l o n g w i t h the uv a b s o r p t i o n maxima o f a number o f s i m p l e a,3-unsaturated e s t e r s a r e summarized i n T a b l e 8. I n c o n n e c t i o n w i t h the d a t a t a b u l a t e d i n T a b l e 8, the f o l l o w i n g p o i n t s s h o u l d be n o t e d . Compared w i t h e t h y l a c r y l a t e t h e a b s o r p t i o n maxima o f t h e e t h y l B - t r i a l k y l s t a n n y l -a c r y l a t e s 174, 175, 177, and 178 e x h i b i t e d s i g n i f i c a n t b a t h o chromic s h i f t s ( e n t r y 1 y_£ e n t r i e s 2, 3, 4, and 5, T a b l e 8 ) . The i n c r e m e n t a s s o c i a t e d w i t h t h e t r i m e t h y l s t a n n y l d e r i v a t i v e s 174 and 175 (17 and 18 nm, r e s p e c t i v e l y ) was l e s s t han t h a t a s s o c i a t e d w i t h the t r i - n - b u t y l d e r i v a t i v e s 177 and 178 (30 and 32 nm, r e s p e c t i v e l y ) . However, t h e magnitude o f the e x t i n c t i o n c o e f f i c i e n t s (e) o f t h e t r i m e t h y l s t a n n y l derivatives (174 and 17 5) were larger than those of the corresponding tri-n-butylstannyl derivatives (177 and 178). These observations p a r a l l e l those made for the TT-^TT* absorp-tion maxima i n the uv spectra of the g - t r i a l k y l s t a n n y l enones described e a r l i e r . It has been found that the average value of the absorp-tion maxima ( T T - * T T * ) of the monosubstituted 0 - a l k y l - a , 3-unsaturated 6 6 esters i s approximately 208 nm. The maxima of the g-trimethylstannyl-3-alkyl-a,3-unsaturated esters outlined i n Table 8 ranged between 216-220 nm. Thus, the magnitude of the increment associated with the 3-trimethylstannyl group in the l a t t e r compounds was 8-12 nm. For example, ethyl (Z^-3-trimethylstannyl-2-butenoate 166 showed an absorption maximum at 218.5 nm which was 10.5 nm higher than that reported for ethyl (E)-2-butenoate 183 (entries 8 and 10, Table 8). The stereochemical e f f e c t s on the position of the absor-ption maxima of the g-trialkylstannyl-a,3-unsaturated esters were small. For example, both ethyl (E)-3-trimethylstannyl-2-butenoate 163 and the corresponding (Z^-isomer 166 exhib-i t e d abosprtion maxima at 218.5 nm (entries 11 and 12, Table 8). This i s consistent with that observed for other a , g -6 7 unsaturated systems. For example, the absorption maximum of methyl (E)-2-butenoate 134 i s 204.5 nm while that of the corresponding (Z^-isomer 182 i s 205.5 nm (entries 6 and 7, Table 8). The stereochemical e f f e c t s on the in t e n s i t y of the absorption maxima of the g-trialkylstannyl-a,g-unsaturated - 86 -e s t e r s were found to be q u i t e s i g n i f i c a n t . In g e n e r a l , the magnitude of the e x t i n c t i o n c o e f f i c i e n t s (e) a s s o c i a t e d w i t h the a b s o r p t i o n maxima of the (E) - isomers were l a r g e r than those a s s o c i a t e d w i t h the (Z)- isomers. For example, the e x t i n c t i o n c o e f f i c i e n t of e t h y l ( E ) - 3 - t r i m e t h y l s t a n n y l - 2 -butenoate 163 was 14,8 00, c o n s i d e r a b l y l a r g e r than t h a t of the corresponding (Z)- isomer 166 (e= 9,300) ( e n t r i e s 11 and 12, Table 8 ) . However, i t should a l s o be noted t h a t the e x t i n c t i o n c o e f f i c i e n t of e t h y l (E)-4,4-dimethyl-3-t r i m e t h y l s t a n n y l - 2 - p e n t e n o a t e 165 (e = 6,900) was l e s s than t h a t a s s o c i a t e d w i t h the (Z_) - isomer 168 (e= 9,8 00) ( e n t r i e s 15 and 16, Table 8 ) . Presumably, i n the (E)-isomer 165 ( t e r t - b u t y l c i s to C 0 2 E t ) the bulky t e r t - b u t y l group causes some l o s s of p l a n a r i t y of the a,B-unsaturated system by s t e r i c hinderance. In g e n e r a l , l i t h i u m p h e n y l t h i o ( t r i m e t h y l s t a n n y l ) c u p r a t e 72 smoothly t r a n s f e r r e d one Me^Sn group to 0 - a l k y l a , B - a c e t y l e n i c e s t e r s . The course of t h i s r e a c t i o n can be c o n t r o l l e d e x p e r i m e n t a l l y so as to produce, h i g h l y s t e r e o s e l e c t i v e l y , e i t h e r the (E)- or the ( Z ) - B - t r i m e t h y l s t a n n y l - a , 3 - u n s a t u r a t e d e s t e r s . I t was a l s o found t h a t the t r i a l k y l s t a n n y l c o p p e r reagents 9_4 and 181 r e a c t e d smoothly w i t h e t h y l (Z_)-3-t o s y l o x y a c r y l a t e 180 to a f f o r d the corres p o n d i n g (Z_)-3-t r i a l k y l s t a n n y l a c r y l a t e s 175 and 178, r e s p e c t i v e l y . Furthermore, a l l of the 8 - t r i a l k y l s t a n n y l - c t , B-unsaturated - 8 7 -T a b l e 8. The UV A b s o r p t i o n Maxima (\ ) o f some max a , 6 - U n s a t u r a t e d E s t e r s and B - T r i a l k y l s t a n n y l -ct, 8-Unsaturated E s t e r s E n t r y ct, 6-Unsaturated E s t e r Observed X (nm)(E) Ref, rricix C02Et 195.8 ( l l , 5 0 0 ) b 68 Me^ IT* CO^t 213 (11,800) 175 214 (6,900) n- Bu^Sn 177 CC^Et 226 (6,600) n-Bu-,Sn COoEt " w 178 228 (3,500) Me COzMe 132 205.5 (14,000)° 69 Me 183 COjMe 204.5 (16,500)* 69 - 83 -CC^Et f=/ 208 (13,115) Me is* 163 Me 3 Sn C02Et 10 218.5 (9,100) Me 166 157 164 167 165 Me 3 Sn C02Et 168 c Me^Sn M / c O j E t 2 1 8 - 5 (14,800) Me 3 Sn 11 220 (13,800) Et CO^t 156 Me 3 Sn C02Et 12 218 (9,300) Me 3 Sn 13 ) = \ 217 (12,200) r t-BuMejSO Me 3 Sn C0 2Me 14 * 218 (8,900) r t-BuMe^SO Me 3Sn 1 5 t - B u ^ C 0 2 E t 2 1 6 ( 6 ' 9 0 ° ) 16 218 (9,800) t-Bu 70 a T h e uv s p e c t r a o f t h e B - t r i a l k y l s t a n n y l e s t e r s were r e c o r d e d u s i n g methanol as t h e s o l v e n t , was t h e s o l v e n t . c E t O H was th e s o l v e n t - 90 -and ( E ) - 4 - l i t h i o - l , 3 - p e n t a d i e n e s 186 and 187, r e s p e c t i v e l y . These l a t t e r s p e c i e s c o u l d then be a l l o w e d t o r e a c t w i t h a v a r i e t y o f e l e c t r o p h i l i c r e a g e n t s . R e d u c t i o n o f e t h y l ( E ) - 3 - t r i m e t h y l s t a n n y l - 2 - b u t e n o a t e 71 163 w i t h ^1 e q u i v a l e n t o f d u s o b u t y l a l u m i n u m h y d r i d e (DIBAL) i n n-pentane a t -127°C f o r l h gave, a f t e r chromato-graphy of the crude p r o d u c t on s i l i c a g e l , the aldehyde 188 i n 86% y i e l d . A s m a l l amount (5%) o f the a l c o h o l 189 was a l s o i s o l a t e d from t h i s r e a c t i o n . However, the l a t t e r compound c o u l d be smoothly o x i d i z e d t o the aldehyde 188 by t r e a t m e n t w i t h b a r i u m manganate i n d i c h l o r o m e t h a n e 72 (eq. 5 1 ) . The s t r u c t u r e s a s s i g n e d t o the r e a c t i o n p r o d u c t s BaMn04 (51) 163 188 189 were i n f u l l a c c o r d w i t h t h e i r s p e c t r a l d a t a . The i r spectrum of 188 showed a s t r o n g a b s o r p t i o n band a t 1675 cm 1 which i n d i c a t e d the p r e s e n c e o f an a , 3 - u n s a t u r a t e d a l d e h y d e . The "*"H nmr spectrum o f t h i s m a t e r i a l e x h i b i t e d a n i n e - p r o t o n s i n g l e t a t 60.19 ( w i t h s a t e l l i t e peaks due t o t i n c o u p l i n g , J„ =54Hz) which c o u l d be a t t r i b u t e d t o the t r i m e t h y l s t a n n y l Sn-H group. The v i n y l m e t h y l p r o t o n s gave r i s e t o a t h r e e - p r o t o n d o u b l e t (J=2Hz) a t 62.46 ( w i t h s a t e l l i t e peaks, J _ =48Hz), b n - n w h i l e the o l e f i n i c p r o t o n gave r i s e t o a o n e - p r o t o n d o u b l e t • o f q u a r t e t s (J=2Hz, J =7Hz) a t 66.21 ( s a t e l l i t e peaks, J„ =68Hz) . There was a l s o p r e s e n t i n the "'"H nmr spectrum fan—n of 188 a one p r o t o n d o u b l e t (j'=7Hz) a t 610.05, w h i c h c l e a r l y c o n f i r m e d the p r e s e n c e o f t h e a l d e h y d e f u n c t i o n a l i t y . The i r spectrum o f the a l c o h o l 189 e x h i b i t e d a broad a l c o h o l a b s o r p t i o n a t 3220 cm . I n the "*"H nmr spectrum o f t h i s m a t e r i a l the t r i m e t h y l s t a n n y l p r o t o n s gave r i s e t o a n i n e - p r o t o n s i n g l e t a t 60.12 ( w i t h s a t e l l i t e peaks due t o t i n c o u p l i n g J g n _ H = 5 2 H z ) . A broad two-proton d o u b l e t (J^6Hz) a t 6 4.26 c o u l d be a t t r i b u t e d t o the hydroxymethylene p r o t o n s . The o l e f i n i c p r o t o n appeared as a o n e - p r o t o n t r i p -l e t o f q u a r t e t s (J=2Hz, j'=6Hz) a t 55.80 ( w i t h s a t e l l i t e p e a k s, J„ T=78Hz). r Sn-H Treatment o f the aldehyde 188 w i t h 1.3 e q u i v a l e n t s o f 73 m e t h y l e n e t n p h e n y l p h o s p h o r a n e i n t e t r a h y d r o f u r a n a t room temperature f o r 2h gave the ( E ) - t r i m e t h y l s t a n n y l d i e n e 184 i n 74% y i e l d (eq. 5 2 ) . The s t r u c t u r e a s s i g n e d t o 184 was c o n f i r m e d by i t s s p e c t r a l d a t a . The uv spectrum o f t h i s m a t e r i a l e x h i b i t e d a s t r o n g a b s o r p t i o n a t 236 nm, w i t h E= 22,700 (TT-*TT* o f 1 , 3 - d i e n e ) . Two a b s o r p t i o n bands a t - 92 -Me3Sn Ph3P=CH2 Me3Sn H d y=\ — > >=<_^b ( 5 2 ) / CHO ' 188 ' c 184 to H 1620 and 1575 cm 1 i n the i r spectrum a l s o i n d i c a t e d the presence o f a 1,3-diene. In the nmr spectrum o f t h i s compound the t r i m e t h y l s t a n n y l p r o t o n s gave r i s e t o a n i n e -p r o t o n s i n g l e t a t 6 0.16 ( w i t h s a t e l l i t e peaks due t o t i n c o u p l i n g , J g n _ H = 5 3 H z ) . A one-pr o t o n d o u b l e t o f d o u b l e t s (J ak=2Hz, Jj_ ) c=16Hz) c e n t e r e d a t 65.10 and a on e - p r o t o n d o u b l e t o f d o u b l e t s ( J a b = 2 H z , J b c=16Hz) c e n t e r e d a t 65.17 were a t t r i b u t e d t o the two g e m i n a l o l e f i n i c p r o t o n s H and 3. H^, r e s p e c t i v e l y . A o n e - p r o t o n d o u b l e t o f q u a r t e t s (J c^=10.5Hz, i J =2Hz) due t o was c e n t e r e d a t 66.16 ( s a t e l l i t e p eaks, J c _ =72Hz), w h i l e a o n e - p r o t o n m u l t i p l e t ( J =10Hz, J, =16Hz, J =10.5Hz) due t o H was c e n t e r e d a t 66.76. be cd c The ( Z ) - 4 - t r i m e t h y l s t a n n y l - l , 3 - p e n t a d i e n e 185 was p r e p a r e d from t h e ( Z ) - 3 - t r i m e t h y l s t a n n y l e s t e r 166 i n a s i m i l a r manner. R e d u c t i o n o f 166 w i t h ^1 e q u i v a l e n t o f d i i s o b u t y l a l u m i n u m h y d r i d e ^ 1 (DIBAL) (pentane, -127°C, l h ) - 93 -a f f o r d e d the aldehyde 190 and the a l c o h o l 191 i n 82% and 7% y i e l d s , r e s p e c t i v e l y (eq. 53) . The l a t t e r c o u l d be smoothly o x i d i z e d t o the aldehyde 190 by t r e a t m e n t w i t h 72 barium manganate i n d i c h l o r o m e t h a n e . Treatment o f the aldehyde 190 w i t h 1.3 e q u i v a l e n t s o f m e t h y l e n e t r i p h e n y l -7 3 phosphorane (THF, room t e m p e r a t u r e , 2h) gave the d i e n e BaMnQi V MeoSn n n c*. MeoSn ~.,~ MeoSn 3 \ C0 2Et DIBAL 3 \ PHO , e 3 ° ^ 166 / 190 V Ph3P=CH2 PH^OH 191 (53) Me3Sn 185 185 i n 72% y i e l d . The s t r u c t u r e s a s s i g n e d t o the r e a c t i o n p r o d u c t s o u t l i n e d i n e q u a t i o n 53 were i n f u l l a c c o r d w i t h t h e i r s p e c t r a l d a t a . T r a n s m e t a l a t i o n o f the d i e n e s 184 and 185 was a c c o m p l i s h e d - 94 -by t r e a t m e n t o f t h e s e s u b s t a n c e s w i t h 1.2 e q u i v a l e n t s o f m e t h y l l i t h i u m i n t e t r a h y d r o f u r a n (-78°C, 10 m i n ) . The r e s u l t a n t 4 - l i t h i o - l , 3 - p e n t a d i e n e s (186 and 187) r e a c t e d smoothly w i t h a v a r i e t y o f e l e c t r o p h i l e s ("E+") t o produce the c o r r e s p o n d i n g s u b s t i t u t e d d i e n e s (192 and 193, e q u a t i o n s 54 and 55). Some o f the r e s u l t s which were o b t a i n e d a r e summarized i n Table 9. Each o f the r e a c t i o n p r o d u c t s l i s t e d i n T a b l e 9 e x h i b i t e d s p e c t r a l d a t a i n f u l l a c c o r d w i t h the a s s i g n e d s t r u c t u r e and gave a s a t i s f a c t o r y m o l e c u l a r w e i g h t d e t e r m i n a t i o n ( h i g h r e s o l u t i o n mass s p e c t r o m e t r y ) . MeoSn Li < > ) = \ > 7—\ (54) 184 186 192 MegSn 185 187 193 (55) A t y p i c a l p r o c e d u r e f o r the c o n v e r s i o n o f the s t a n n y l d i e n e s i n t o the c o r r e s p o n d i n g s u b s t i t u t e d d i e n e s f o l l o w s . To a c o l d (-78°C), s t i r r e d s o l u t i o n o f 184 (0.25 mmol) i n 4mL o f anhydrous t e t r a h y d r o f u r a n , under an atmosphere o f arg o n , was added d r o p w i s e a s o l u t i o n o f m e t h y l l i t h i u m i n - 95 -ether (0.30 mmol). The resultant yellow solution was s t i r r e d at -78°C for 10 min. A solution of cyclopentanone (THF, 0.33 mmol) was added and the reaction mixture was s t i r r e d for an additional period of l h . After successive addition of saturated aqueous ammonium chloride and ether, the mixture was allowed to warm to room temperature. The layers were separated and the ether solution was washed with brine and dried over anhydrous magnesium su l f a t e . Evaporation of solvent, followed by d i s t i l l a t i o n (air-bath) of the residual o i l gave 28 mg (74%) of pure (E)-4-(1-hydroxycyclopentyl)-1, 3-pentadiene 197 (entry 4, Table 9 ) . The id e n t i t y of thi s material was confirmed by i t s spectral data. In connection with the data summarized i n Table 9 the following points should be noted. In each case a s l i g h t excess (1.3 equivalents) of the ele c t r o p h i l e was used. When the e l e c t r o p h i l e was an a l k y l halide, the reaction mixture was s t i r r e d at -7 8°C for l h , allowed to warm to room temperature over a period of l h , and then quenched with aqueous ammonium chloride. The reaction product was then separated from recovered a l k y l halide by preparative t i c on 12% (w/w) s i l v e r n i t r a t e - s i l i c a gel (entries 1, 2, and 5, Table 9 ) . With carbonyl e l e c t r o p h i l e s , the reaction mixture was s t i r r e d at -78°C for l h and treated at this temperature with aqueous ammonium chloride. The reaction product was then p u r i f i e d by a simple d i s t i l l a t i o n (air bath) (entries 3, 4, and 6, Table 9 ) . - 96 -Table 9. R e a c t i o n o f the 4 - L i t h i o - l , 3 - p e n t a d i e n e s 18 6 and 187 w i t h E l e c t r o p h i l e s E n t r y N u c l e o p h i l e E l e c t r o p h i l e P r o d u c t E i n 192 and 193 (% Y i e l d ) 1 186 n - C 8 H 1 7 B r 194 E=n-C 8H 1 7 (71) 2 186 RCH 2CH 2Br C 195 E=RCH 2CH 2° (69) 3 186 RCH 2CHO° 196 E=RCH 2CH(OH)° (82) 4 186 c y c l o p e n t a n o n e 197 E=l-hydroxy-c y c l o p e n t y l (74) 5 187 n - C 8 H 1 7 B r 198 E=n-C 8H 1 7 (62) 6 187 R-CH 2CH 2CHO 199 E=RCH 2CH(OH) C (76) a A l l r e a c t i o n s were c a r r i e d o u t i n THF. Fo r r e a c t i o n b c o n d i t i o n s see t e x t . Y i e l d o f d i s t i l l e d p u r i f i e d p r o d u c t . R = 2 - c y c l o p e n t e n y l . - 97 -In g e n e r a l , the p r e p a r a t i o n o f the t r i m e t h y l s t a n n y l d i e 184 and 185 from the c o r r e s p o n d i n g e s t e r s 163 and 166 was c a r r i e d o u t i n good y i e l d . These p r o d u c t s were q u i t e s t a b l e and c o u l d be s t o r e d (under an atmosphere o f argon) i n a f r e e z e r f o r s e v e r a l months w i t h o u t s u b s t a n t i a l d e c o m p o s i t i o n . The f o r m a t i o n o f the ( Z ) - and ( E ) - 4 - l i t h i o -3 -pentadienes 18 6 and 187 from the t r i m e t h y l s t a n n y l d i e n e s (184 and 185) was a s i m p l e p r o c e s s . F u r t h e r m o r e , t h e s e l i t h i o r e a g e n t s r e a c t e d smoothly w i t h v a r i o u s e l e c t r o p h i l e s t o produce t h e c o r r e s p o n d i n g s u b s t i t u t e d d i e n e s 192 and 193, r e s p e c t i v e l y . - 98 -EXPERIMENTAL G e n e r a l I n f o r m a t i o n M e l t i n g p o i n t s were d e t e r m i n e d w i t h a F i s h e r - J o h n s m e l t i n g p o i n t a p p a r a t u s and a r e u n c o r r e c t e d . B o i l i n g p o i n t s are a l s o u n c o r r e c t e d and t h o s e i n d i c a t e d as a i r - b a t h temp-e r a t u r e s r e f e r t o s h o r t p a t h ( K u g e l r o h r ) d i s t i l l a t i o n s . U l t r a v i o l e t (uv) s p e c t r a were o b t a i n e d i n methanol s o l u t i o n w i t h a Cary 15 s p e c t r o p h o t o m e t e r . I n f r a r e d ( i r ) s p e c t r a were r e c o r d e d on P e r k i n Elmer model 710 or 710B i n f r a r e d s p e c t r o p h o t o m e t e r s and were c a l i b r a t e d u s i n g the 1601 cm 1 band o f p o l y s t y r e n e f i l m . The p r o t o n n u c l e a r magnetic resonance ("''H nmr) s p e c t r a were t a k e n i n d e u t e r o c h l o r o f o r m s o l u t i o n and r e c o r d e d u s i n g V a r i a n A s s o c i a t e s T-60, HA-100 or XL-100 s p e c t r o m e t e r s o r a B r u k e r WP-80 s p e c t r o m e t e r . The 270 MHz s p e c t r a were r e c o r d e d on a u n i t c o m p r ised o f an O x f o r d I n s t r u m e n t s 63.4 KG s u p e r c o n d u c t i n g magnet and a N i c o l e t 16K computer a t t a c h e d t o a B r u k e r TT-23 c o n s o l e . A l l nmr s p e c t r a were e i t h e r 8 0 o r 100 MHz s p e c t r a u n l e s s s t a t e d o t h e r w i s e . S i g n a l p o s i t i o n s a r e g i v e n i n p a r t s per m i l l i o n (ppm) d o w n f i e l d from t e t r a m e t h y l s i l a n e (TMS) as i n t e r n a l s t a n d a r d . I n c a s e s o f compounds c o n t a i n i n g t r i m e t h y l s t a n n y l and/or t r i a l k y l s i l y l groups t h e resonance p o s i t i o n s were d e t e r m i n e d r e l a t i v e t o the c h l o r o f o r m s i g n a l 74 (67.25 ). The m u l t i p l i c i t y , number o f p r o t o n s , c o u p l i n g c o n s t a n t s (where p o s s i b l e ) and assignments a r e i n d i c a t e d - 99 -i n p a r e n t h e s e s . The t i n - p r o t o n c o u p l i n g c o n s t a n t s ( J S n _ H ) ~ 117_ , 1 1 9 e , ar e g i v e n as an average o f the Sn and Sn v a l u e s . Low r e s o l u t i o n mass s p e c t r a were r e c o r d e d w i t h a Varian/MAT CH4B mass s p e c t r o m e t e r . High r e s o l u t i o n mass s p e c t r a were r e c o r d e d w i t h a K r a t o s / A E I MS 50 or MS 902 mass s p e c t r o m e t e r . In c a s e s o f compounds c o n t a i n i n g t r i a l k y l s t a n n y l groups t h e m o l e c u l a r w e i g h t d e t e r m i n a t i o n s ( h i g h r e s o l u t i o n mass 120 s p e c t r o m e t r y ) were based on Sn. M i c r o a n a l y s e s were performed by Mr. P. Borda, M i c r o a n a l y t i c a l L a b o r a t o r y , U n i v e r s i t y o f B r i t i s h Columbia. A n a l y t i c a l gas l i q u i d chromatography ( g l c ) was performed on a H e w l e t t - P a c k a r d HP 5832A gas chromatograph. The f o l l o w -i n g columns were used: (A) 6 f t x 0.125 i n , 3-5% OV-17 on Chromosorb W (HP) (80-100 mesh); (B) 6 f t x 0.125 i n , 5% OV-210 on Chromosorb W (HP) (80-100 mesh). P r e p a r a t i v e g l c was done u s i n g a V a r i a n A erograph 90-P gas chromatograph on t h e f o l l o w i n g c o l u m n : (C) 1 0 f t x 0.25 i n , 10% OV-17 on Chromosorb W (60-80 mesh). T h i n l a y e r chromatography ( t i c ) was c a r r i e d o ut on 20 x 5 cm g l a s s p l a t e s c o a t e d w i t h 0.5 mm o f s i l i c a g e l (E. Merck, S i l i c a G e l 60) o r on commercial s i l i c a g e l p l a t e s (Eastman Chromagram Sheet Type 13181). P r e p a r a t i v e t h i n l a y e r chromatography was c a r r i e d o u t on 20 x 20 cm g l a s s p l a t e s c o a t e d w i t h 0.7 mm o f s i l i c a g e l (E. Merck, S i l i c a G e l 6 0 ) . Column chromatography was done on e i t h e r s i l i c a g e l (E. Merck, 70-230 mesh) o r f l o r i s i l ( J . T. Baker C h e m i c a l Co., 100-200 mesh). - 100 -A l l r e a c t i o n s i n v o l v i n g a i r and m o i s t u r e s e n s i t i v e r e a g e n t s were c a r r i e d o u t under an atmosphere o f argon u s i n g e i t h e r oven o r c a r e f u l l y flame d r i e d g l a s s w a r e . S o l v e n t s and Reagents H e x a m e t h y l d i t i n and h e x a - n - b u t y l d i t i n were o b t a i n e d from the A l f a D i v i s i o n o f the V e n t r o n C o r p o r a t i o n and were p u r i f i e d (when n e c e s s a r y ) by d i s t i l l a t i o n . S o l u t i o n s o f m e t h y l l i t h i u m and n - b u t y l l i t h i u m were o b t a i n e d from A l d r i c h C h e m i c a l Co., I n c . and were s t a n d a r d i z e d 7 5 u s i n g Gilman's p r o c e d u r e . 3-Iodo enones were p r e p a r e d by the r e a c t i o n o f c y c l i c 3 - d i k e t o n e s (or a-( h y d r o x y m e t h y l e n e ) c y c l o h e x a n o n e ) w i t h 2 t r i p h e n y l p h o s p h m e d u o d i d e i n the presence o f t r i e t h y l a m i n e . L i t h i u m d i i s o p r o p y l a m i d e (LDA) was p r e p a r e d by the a d d i t i o n o f a s o l u t i o n o f n - b u t y l l i t h i u m i n hexane t o a s o l u t i o n o f d i i s o p r o p y l a m i n e (1.1 eq u i v . ) i n anhydrous t e t r a h y d r o f u r a n a t -78°C under argon. The r e s u l t i n g s o l u t i o n was then s t i r r e d a t 0°C f o r 10 min b e f o r e b e i n g used. 31 P h e n y l t h i o c o p p e r was p r e p a r e d by r e f l u x i n g a m i x t u r e of cuprous o x i d e (36g, 0.25 mmol) and t h i o p h e n o l (63g, 0.57 mmol) i n a b s o l u t e e t h a n o l (1000 mL) f o r seven days. The r e s u l t a n t y e l l o w s l u r r y was s u c t i o n f i l t e r e d , washed t h o r o u g h l y w i t h e t h a n o l , and d r i e d f o r s e v e r a l days under h i g h vacuum. The y i e l d o f p h e n y l t h i o c o p p e r was e s s e n t i a l l y q u a n t i t a t i v e . Methylenetriphenylphosphorane was prepared by the addition of a solution of n-butyllithium in hexane to a cold (-78°C), s t i r r e d suspension of (methyl)triphenyl-phosphonium bromide (1 equiv.) i n anhydrous tetrahydrofuran under argon. The r e s u l t i n g mixture was then s t i r r e d at room temperature for 4 5 min to afford a yellow solution of methylenetriphenylphosphorane. Tetrahydrofuran (THF) and d i e t h y l ether were d i s t i l l e d 7 6 from lithium aluminum hydride or sodium benzophenone k e t y l . Triethylamine and diisopropylamine were d i s t i l l e d from calcium hydride and kept over 4$ molecular sieves or a piece of calcium hydride. Pentane was also d i s t i l l e d from calcium hydride. Hexamethylphosphoramide (HMPA) was d i s t i l l e d from barium oxide and stored over 13x molecular sieves. Dichloromethane and a c e t o n i t r i l e were both d i s t i l l e d from phosphorous pentoxide and a c e t o n i t r i l e was stored over o 4A molecular sieves. N,N-Dimethylformamide was d i s t i l l e d from calcium hydride o and sequentially dried over 4A molecular sieves. Anhydrous methanol was obtained by d i s t i l l i n g methanol from magnesium methoxide. D i s t i l l a t i o n from magnesium ethoxide afforded dry ethanol. - 102 -Typical Procedures for the Preparation of T r i a l k y l s t a n n y l  Reagents 24 Preparation of Trimethylstannyllithium To a cold (-20°C) s t i r r e d solution of hexamethylditin in anhydrous tetrahydrofuran, under an atmosphere of argon, was added a solution of methyllithium i n ether (1.0 equiv-alent) . The resultant mixture was s t i r r e d at -20°C for 15 min to afford a yellow solution of trimethylstannyllithium. 24 74 Preparation of Tri-n-butylstannyllithium ' To a cold (0°C) s t i r r e d solution of hexa-n-butylditin in anhydrous tetrahydrofuran, under an atmosphere of argon, was added a solution of n-butyllithium i n hexane (1.0 equiv-alent) . The resultant mixture was s t i r r e d at 0°C for 15 min to give a yellow solution of tri-n-butylstannyllithium. Preparation of Lithium Phenylthio(trimethylstannyl)cuprate 72 PhS(Me3Sn)CuLi 72 To a cold (-20°C), s t i r r e d solution of trimethylstannyllithium (0.75 mmol, prepared as outlined above) i n 10 mL of anhydrous tetrahydrofuran, under an atmosphere of argon, was added in one portion s o l i d phenylthiocopper (132 mg, 0.75 mmol). The re s u l t i n g yellow slur r y was s t i r r e d at -20°C for 15 min to - 103 -a f f o r d a dark r e d s o l u t i o n o f l i t h i u m p h e n y l t h i o ( t r i m e t h y l -s t a n n y l ) c u p r a t e 7_2 (0.75 mmol). P r e p a r a t i o n o f L i t h i u m P h e n y l t h i o ( t r i - n - b u t y l s t a n n y l ) c u p r a t e 73 PhS(n-Bu3Sn)CuLi 73 To a c o l d (-20°C), s t i r r e d s o l u t i o n o f t r i - n - b u t y l s t a n n y l -l i t h i u m (0.55 mmol, p r e p a r e d as o u t l i n e d above) i n 10 mL o f anhydrous t e t r a h y d r o f u r a n , under an atmosphere o f arg o n , was added s o l i d p h e n y l t h i o c o p p e r (97 mg, 0.55 mmol) i n one p o r t i o n . The r e s u l t i n g y e l l o w s l u r r y was s t i r r e d a t -20°C f o r 15 min to a f f o r d a dark r e d s o l u t i o n o f the c u p r a t e r e a g e n t 7_3 (0.55 mmol). P r e p a r a t i o n o f the L i t h i u m B i s ( t r i m e t h y l s t a n n y l ) c u p r a t e  Reagent 93 (N/^Sn^CuLi •SMe2 93 To a c o l d (-48°C), s t i r r e d s o l u t i o n o f t r i m e t h y l s t a n n y l -l i t h i u m (1.1 mmol, p r e p a r e d as o u t l i n e d above) i n 10 mL o f anhydrous t e t r a h y d r o f u r a n , under an atmosphere o f argon, was added i n one p o r t i o n s o l i d d i m e t h y l s u l f i d e - c u p r o u s bromide - 104 -(117 mg, 0.55 mmol). The r e s u l t i n g m i x t u r e was s t i r r e d a t -48°C f o r 20 min t o a f f o r d a d a r k r e d s o l u t i o n . o f the c u p r a t e r e a g e n t 93_ (0.55 mmol). P r e p a r a t i o n o f the T r i m e t h y l s t a n n y l c o p p e r Reagent 94 MegSnCu • Li Br • SMe2 94 To a c o l d (-48°C), s t i r r e d s o l u t i o n o f t r i m e t h y l s t a n n y l -l i t h i u m (0.65 mmol, p r e p a r e d as o u t l i n e d above) i n 5 mL o f anhydrous t e t r a h y d r o f u r a n , under an atmosphere o f a r g o n , was added i n one p o r t i o n s o l i d d i m e t h y l s u l f i d e - c u p r o u s bromide (133 mg, 0.65 mmol). The r e s u l t i n g m i x t u r e was s t i r r e d a t -48°C f o r 10 min t o g i v e a dark r e d s o l u t i o n o f 9_4 (0.65 mmol). P r e p a r a t i o n o f the T r i - n - b u t y l s t a n n y l c o p p e r Reagent 181 n-BugSnCu-LiBr'SN/^ 181 To a c o l d (-48°C), s t i r r e d s o l u t i o n o f t r i - n - b u t y l s t a n n y l -l i t h i u m (0.60 mmol, p r e p a r e d as o u t l i n e d e a r l i e r ) i n anhydrous t e t r a h y d r o f u r a n (5 mL), under an atmosphere o f a r g o n , was added i n one p o r t i o n s o l i d d i m e t h y l s u l f i d e - c u p r o u s bromide (123 mg, 0.60 mmol). The r e s u l t i n g d a r k r e d m i x t u r e was s t i r r e d a t -48°C f o r 10 min t o a f f o r d the copper r e a g e n t 181 (0.60 mmol). - 105 -P r e p a r a t i o n o f g - T r i a l k y l s t a n n y l Enones  G e n e r a l P r o c e d u r e A To a c o l d (-20°C), s t i r r e d s o l u t i o n o f l i t h i u m p h e n y l t h i o -( t r i m e t h y l s t a n n y l ) c u p r a t e 7_2_ (0.75 mmol) i n 10 mL o f anhydrous t e t r a h y d r o f u r a n , under an atmosphere o f a r g o n , was added a s o l u t i o n (THF, ^ 1 mL) o f the a p p r o p r i a t e 3-iodo enone. The r e s u l t i n g d a r k r e d m i x t u r e was s t i r r e d a t -20°C f o r 15 min, warmed t o room t e m p e r a t u r e , and s t i r r e d f o r an a d d i t i o n a l p e r i o d o f 30 min. Methanol (^0.2 mL) and e t h e r (^30 mL) were added, and the m i x t u r e was s t i r r e d a t room temperature f o r s e v e r a l m i n u t e s . The r e s u l t i n g y e l l o w s l u r r y was f i l t e r e d t h r o u g h a s h o r t column o f f l o r i s i l (10 g, 100-200 mesh). The column was e l u t e d w i t h a f u r t h e r 50 mL o f e t h e r and the e l u a n t was combined. Removal o f the s o l v e n t , f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h ) o f the r e s i d u a l o i l a f f o r d e d the c o r r e s p o n d i n g p r o d u c t . G e n e r a l P r o c e d u r e B To a c o l d (-48°C), s t i r r e d s o l u t i o n o f the t r i m e t h y l s t a n n y l -copper r e a g e n t 9_4 (0.65 mmol) i n 5 mL o f anhydrous t e t r a h y d r o -f u r a n , under an atmosphere o f arg o n , was added a s o l u t i o n o f the a p p r o p r i a t e B-iodo enone (0.50 mmol) i n anhydrous t e t r a -h y d r o f u r a n (^0.5 mL). The dark r e d s o l u t i o n was s t i r r e d a t -48°C f o r 2h, warmed t o -20°C, and s t i r r e d a t t h i s t e mperature f o r l h . S a t u r a t e d (pH 8) aqueous ammonium c h l o r i d e (^ 5 mL) and e t h e r (^3 0 mL) were added, and the r e s u l t i n g m i x t u r e was - 106 -s t i r r e d f o r s e v e r a l m i n u t e s . The e t h e r l a y e r was s e p a r a t e d , washed w i t h pH 8 s a t u r a t e d aqueous ammonium c h l o r i d e , and d r i e d o v e r anhydrous magnesium s u l f a t e . Removal o f the s o l v e n t , f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h ) a f f o r d e d the c o r r e s p o n d i n g p r o d u c t . G e n e r a l P r o c e d u r e C To a c o l d (-20°C), s t i r r e d s o l u t i o n o f l i t h i u m p h e n y l t h i o ( t r i - n - b u t y l s t a n n y l ) c u p r a t e 7_3 (0.55 - 0.65 mmol) i n 10 mL o f anhydrous t e t r a h y d r o f u r a n , under an atmosphere of a r g o n , was added a s o l u t i o n (THF, ^ 0.5 mL) o f the a p p r o p r i a t e g-iodo enone. The r e a c t i o n m i x t u r e was s t i r r e d a t -20°C f o r 15 min and a t room temperature f o r 30 min. Methanol (^0.2 mL) and e t h e r (*^ 30 mL) were s e q u e n t i a l l y added and the r e s u l t i n g m i x t u r e was s t i r r e d a t room temper-a t u r e f o r s e v e r a l m i n u t e s . The r e s u l t a n t y e l l o w s l u r r y was f i l t e r e d t h r o u g h a s h o r t column o f f l o r i s i l (10 g, 100-200 mesh). The column was e l u t e d w i t h a f u r t h e r 50 mL of e t h e r and the e l u a n t was combined. Removal o f the s o l v e n t a f f o r d e d a y e l l o w o i l , w h i c h was chromatographed on 20g o f s i l i c a g e l . E l u t i o n o f t h e column w i t h a 9:1 m i x t u r e o f p e t r o l e u m e t h e r and e t h e r gave, a f t e r c o n c e n t r a t i o n o f the a p p r o p r i a t e f r a c t i o n s , a m i x t u r e o f t e t r a - n - b u t y l t i n and h e x a - n - b u t y l d i t i n . F u r t h e r e l u t i o n o f the column gave, a f t e r c o n c e n t r a t i o n o f t h e a p p r o p r i a t e f r a c t i o n s and d i s t i l l a t i o n ( a i r - b a t h ) o f the r e s i d u e , the c o r r e s p o n d i n g B - t r i - n - b u t y l s t a n n y l enone. - 107 -P r e p a r a t i o n o f 3 - T r i m e t h y l s t a n n y l - 2 - c y c l o h e x e n - l - o n e 70 A I 7_0 a) R e a c t i o n o f T r i m e t h y l s t a n n y l l i t h i u m w i t h  3 - I o d o - 2 - c y c l o h e x e n - l - o n e 63 To a c o l d (-78°C), s t i r r e d s o l u t i o n o f t r i m e t h y l s t a n n y l -l i t h i u m (0.5 mmol) i n 10 mL o f anhydrous t e t r a h y d r o f u r a n , under an atmosphere o f arg o n , was added a s o l u t i o n (THF, ^ 0.25 mL) o f 3 - i o d o - 2 - c y c l o h e x e n - l - o n e 63 (111 mg, 0.5 mmol). The r e s u l t a n t orange s o l u t i o n was s t i r r e d a t -78°C f o r l h . S a t u r a t e d aqueous ammonium c h l o r i d e (^ 5 mL) and e t h e r (^30 mL) were s e q u e n t i a l l y added and the r e s u l t i n g m i x t u r e was a l l o w e d t o warm t o room t e m p e r a t u r e . The e t h e r l a y e r was s e p a r a t e d , washed w i t h b r i n e , and d r i e d o v e r anhydrous magnesium s u l f a t e . Removal o f t h e s o l v e n t , f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 65-69°C, 0.15 t o r r ) o f the r e s i d u e a f f o r d e d a y e l l o w o i l (110 mg). A g l c a n a l y s i s (column A) o f t h i s m a t e r i a l showed t h a t i t was composed o f a m i x t u r e o f t h e ket o n e s 7_0 (^32%) and 7_1 (^15%) , a l o n g w i t h the s t a r t i n g m a t e r i a l 6_3 (M2%) . Other minor u n i d e n t i f i e d p r o d u c t s were a l s o p r e s e n t . A pure sample o f each o f the major p r o d u c t s was o b t a i n e d by p r e p a r a t i v e g l c (column C, 180°C). SnMec SnMe' - 108 -T i c and g l c a n a l y s e s ( s i l i c a g e l and column A, r e s p e c t -i v e l y ) o f the p u r i f i e d 3 - t r i m e t h y l s t a n n y l - 2 - c y c l o h e x e n - l - o n e 70 showed t h e p r e s e n c e o f one component. T h i s m a t e r i a l e x h i b i t e d uv (MeOH) A : 236 nm (e= 12,000); i r ( f i l m ) : max 1670, 1582, 766 cm" 1; 1 H nmr (CDC1 3) 6: 0.17 ( s , 9H, s t a n n y l m e t h y l s , J c =54Hz), 1.82-2.14 fa, 2H, -CH„CH 0CH 0-), 2.28-on—n Z. — Z z 2.66 (m, 4H, -CH 2CH 2CH 2-), 6.22 ( t , IH, o l e f i n i c p r o t o n , J^2Hz, J _ =64Hz). E x a c t mass c a l c d . f o r C nH.,OSn: Sn-H 9 16 260.0223; found: 260.0216. The pure c r y s t a l l i n e 3 , 3 - b i s ( t r i m e t h y l s t a n n y l ) c y c l o -hexanone 71_ e x h i b i t e d mp 50-51°C; i r (CDClj) : 1701 cm" 1; 1H nmr (CDC1,,) 6: 0.04 ( s , 18H, s t a n n y l m e t h y l s , J 0„ =49Hz), J on—rl 1.76-2.18 (m, 4H, -CH_2CH2- (SnR 3) -) , 2.18-2.46 (m, 2H, -CO-CH 2CH 2-), 2.67 (broad s, 2H, -C)-CH 2C(SnR 3) - ) . A n a l , c a l c d . f o r C 1 2 H 2 6 O S n 2 : C 34.02, H 6.19; Found: C 34.08, H 6.26. b) R e a c t i o n o f L i t h i u m P h e n y l t h i o ( t r i m e t h y l s t a n n y l ) c u p r a t e 72 w i t h 3 - I o d o - 2 - c y c l o h e x e n - l - o n e 63 F o l l o w i n g the g e n e r a l p r o c e d u r e A o u t l i n e d above, 0.75 mmol o f l i t h i u m p h e n y l t h i o ( t r i m e t h y l s t a n n y l ) c u p r a t e 7_2 was a l l o w e d t o r e a c t w i t h 3 - i o d o - 2 - c y c l o h e x e n - l - o n e 6_3 (151 mg, 0.68 mmol) i n t e t r a h y d r o f u r a n a t -20°C f o r 15 min, and a t room temperature f o r 3 0 min. Normal workup, f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 65-80°C, 0.09 t o r r ) o f the crude p r o d u c t a f f o r d e d 153 mg (86%) o f 3 - t r i m e t h y l s t a n n y l -2 - c y c l o h e x e n - l - o n e 7_0. The s p e c t r a l p r o p e r t i e s o f t h i s m a t e r i a l were i d e n t i c a l w i t h t h o s e r e p o r t e d e a r l i e r . A n a l . - 109 -c a l c d . f o r CgH gOSn: C 41.75, H 6.23; f o u n d : C 41.75, H 6.22. c) R e a c t i o n o f t h e L i t h i u m B i s ( t r i m e t h y l s t a n n y l ) c u p r a t e Reagent 9_3 w i t h 3 - I o d o - 2 - c y c l o h e x e n - l - o n e 6_3 To a c o l d (-48°C), s t i r r e d s o l u t i o n o f t h e b i s c u p r a t e r e a g e n t 9_3 (0.55 mmol) i n 10 mL o f anhydrous t e t r a h y d r o f u r a n , under an atmosphere of a r g o n , was added a s o l u t i o n (THF, ^lmL) of 3 - i o d o - 2 - c y c l o h e x e n - l - o n e 6_3 (111 mg, 0.5 mmol). The r e a c t i o n m i x t u r e was s t i r r e d a t -48°C f o r l h , warmed t o -20°C, and s t i r r e d a t t h i s t e m p e r a t u r e f o r an a d d i t i o n a l p e r i o d o f l h . Methanol (^0.2 mL) and e t h e r (^30 mL) were added, and t h e r e s u l t i n g m i x t u r e was a l l o w e d t o warm t o room t e m p e r a t u r e . The d a r k s l u r r y was f i l t e r e d t h r o u g h a s h o r t column o f f l o r i s i l ( l O g , 100-200 mesh). The column was e l u t e d w i t h a f u r t h e r 50 mL o f e t h e r and the e l u a n t was combined. Removal o f the s o l v e n t , f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 69-83°C, 0.1 t o r r ) o f the r e s i d u a l o i l a f f o r d e d 99 mg (76%) o f 3 - t r i m e t h y l s t a n n y l - 2 - c y c l o h e x e n - l - o n e 73. A g l c a n a l y s i s (column A) o f t h i s m a t e r i a l showed t h a t i t was c o n t a m i n a t e d w i t h a s m a l l amount (^6%) o f the d i a d d i t i o n p r o d u c t 71. d) R e a c t i o n o f Me 3SnCu•LiBr•SMe 2 94 w i t h  3 - I o d o - 2 - c y c l o h e x e n - l - o n e 63 F o l l o w i n g the g e n e r a l p r o c e d u r e B o u t l i n e d above, 0.65 mmol o f the t r i m e t h y l s t a n n y l c o p p e r r e a g e n t 9_4 was a l l o w e d t o r e a c t w i t h 3 - i o d o - 2 - c y c l o h e x e n - l - o n e 6_3 (111 mg, 0.5 mmol) i n t e t r a h y d r o f u r a n a t -4 8°C f o r 2h, -2 0°C f o r l h , and room temperature f o r l h . Normal workup, f o l l o w e d by d i s t i l l a t i o n - 110 -( a i r - b a t h t e m p e r a t u r e 71-79°C, 0.1 t o r r ) o f the r e s i d u a l o i l a f f o r d e d 129 mg (84%) o f 3 - t r i m e t h y l s t a h n y l - 2 - c y c l o h e x e n -1-one 7_0. The s p e c t r a l p r o p e r t i e s o f t h i s m a t e r i a l were i d e n t i c a l w i t h t h o s e r e p o r t e d e a r l i e r . P r e p a r a t i o n o f 3 - T r i - n - b u t y l s t a n n y l - 2 - c y c l o h e x e n - l - o n e 74 \ ^ S n B u n 3 11 F o l l o w i n g the g e n e r a l p r o c e d u r e C o u t l i n e d above, 0.55 mmol o f l i t h i u m p h e n y l t h i o ( t r i - n - b u t y l s t a n n y l ) c u p r a t e 7_3 w a s a l l o w e d t o r e a c t w i t h 3 - i o d o - 2 - c y c l o h e x e n - l - o n e 6_3 (111 mg, 0.50 mmol) i n t e t r a h y d r o f u r a n a t -20°C f o r 15 min, and a t room temperature f o r 3 0 min. Normal workup, f o l l o w e d by column chromatography o f the crude p r o d u c t on s i l i c a g e l and d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 150-158°C, 0.2 t o r r ) o f the o i l o b t a i n e d from the a p p r o p r i a t e f r a c t i o n s a f f o r d e d 157 mg (81%) o f 3 - t r i - n - b u t y l s t a n n y l - 2 - c y c l o h e x e n - l - o n e 74. T h i s m a t e r i a l e x h i b i t e d uv (MeOH) X : 242.5 nm (e= 10,900); max i r ( f i l m ) : 1672, 1575 cm" 1, 1 H nmr (CDClj) 6: 0.78-1.05 (m, 15H, - S n ( CH 2CH 2CH 2CH 3)), 1.08-1.70 (m, 12H, -Sn(CH 2CH 2 C H 2 C H 3 ) 3 ) , 1.82-2.14 (m, 2H, -CH_2CH2-CO-) , 2.30-2.60 (m, 4H, -CH oCH„CH o-C0-), 6.22 ( t , IH, o l e f i n i c p r o t o n , J=2Hz, J _ =57Hz). - I l l -E x a c t mass c a l c d . f o r c 1 8 H 3 4 ° S n : 386.1632; fo u n d : 386.1632. A n a l . c a l c d . f o r C-^H^OSn: C 56.13, H 8.90; found: C 56.22, H 9.00. P r e p a r a t i o n o f 2 - M e t h y l - 3 - t r i m e t h y l s t a n n y l - 2 - c y c l o h e x e n - l - o n e 79 F o l l o w i n g the g e n e r a l p r o c e d u r e A, o u t l i n e d above, 0.7 5 mmol o f l i t h i u m p h e n y l t h i o ( t r i m e t h y l s t a n n y l ) c u p r a t e 7_2 was 2 a l l o w e d t o r e a c t w i t h 2 - m e t h y l - 3 - i o d o - 2 - c y c l o h e x e n - l - o n e 7_5 (160 mg, 0.68 mmol) i n t e t r a h y d r o f u r a n a t -20°C f o r 15 min, and a t room temperature f o r 3 0 min. Normal workup, f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h , 58-69°C, 0.07 t o r r ) o f t h e c r u d e o i l a f f o r d e d 158 mg (84%) o f 2 - m e t h y l - 3 - t r i m e t h y l s t a n n y l - 2 -c y c l o h e x e n - l - o n e 7_9. T i c and g l c a n a l y s e s ( s i l i c a g e l and column A, r e s p e c t i v e l y ) o f t h i s m a t e r i a l showed the p r e s e n c e of one component wh i c h e x h i b i t e d uv (MeOH) A : 250 nm c max ( e = 14,300); i r ( f i l m ) : 1665, 1595, 760 cm" 1; 1 H nmr (CDC1 3) <5: 0.22 ( s , 9H, s t a n n y l m e t h y l s , J c =54Hz), 1.78-2.08 o n — H (m, 2H, -CH2CH_2CH2-) , 1.86 ( t , 3H, v i n y l m e t h y l , J^1.8Hz), 2.32-2.56 (m, 4H, -CH 2CH 2CH 2-). E x a c t Mass c a l c d . f o r C 1 0 H 1 8 0 S n : 2 7 4 - 0 3 7 8 ' * found: 274.0373. P r e p a r a t i o n o f 2 - M e t h y l - 3 - t r i - n - b u t y l s t a n n y l - 2 - c y c l o h e x e n - l - o n e 80 80 F o l l o w i n g the g e n e r a l p r o c e d u r e C, o u t l i n e d above, 0.65 mmol o f l i t h i u m p h e n y l t h i o ( t r i - n - b u t y l s t a n n y l ) c u p r a t e 7_3 was 2 a l l o w e d t o r e a c t w i t h 2 - m e t h y l - 3 - i o d o - 2 - c y c l o h e x e n - l - o n e 7_5_ (118 mg, 0.50 mmol) i n t e t r a h y d r o f u r a n a t -20°C f o r 15 min, and a t room tem p e r a t u r e f o r 30 min. Normal workup, f o l l o w e d by column chromatography o f the crude p r o d u c t on s i l i c a g e l and d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 160-163°C, 0.2 t o r r ) o f the m a t e r i a l o b t a i n e d from the a p p r o p r i a t e f r a c t i o n s a f f o r d e d 157 mg (79%) o f 2 - m e t h y l - 3 - t r i - n - b u t y l s t a n n y l - 2 -c y c l o h e x e n - l - o n e 8_0. T i c and g l c a n a l y s e s ( s i l i c a g e l and column A, r e s p e c t i v e l y ) o f t h i s m a t e r i a l showed the p r e s e n c e o f one component wh i c h e x h i b i t e d uv (MeOH) * m a x : 256 nm (e= 12,000); i r ( f i l m ) : 1677, 1590 cm" 1; 1H nmr (CDC1 3) <5: 0.75-1.09 (m, 15H, -Sn(CH 2CH 2CH 2CH 3) ), 1.11-1.63 (m, 12H, - Sn(CH 2CH 2CH 2CH 3)), 1.29-1.59 (m, 2H, -CH 2CH 2CH 2~), - 113 -1.84 ( t , 3H, v i n y l m e t h y l , J=2Hz), 1.71-2.08 (m, 4H, -CH^Cri^CH^) . E x a c t mass c a l c d . f o r C i g H 3 6 0 S n : 400.1788; Found: 400.1801. P r e p a r a t i o n o f 3 - T r i m e t h y l s t a n n y l - 2 - c y c l o p e n t e n - l - o n e 81 „, SnMeq 81 J a) R e a c t i o n o f L i t h i u m P h e n y l t h i o ( t r i m e t h y l s t a n n y l ) c u p r a t e 7_2 w i t h 3 - i o d o - 2 - c y c l o p e n t e n - l - o n e 8_1 F o l l o w i n g the g e n e r a l p r o c e d u r e A o u t l i n e d above, 0.75 mmol of l i t h i u m p h e n y l t h i o ( t r i m e t h y l s t a n n y l ) c u p r a t e 7_2 was a l l o w e d t o r e a c t w i t h 3 - i o d o - 2 - c y c l o p e n t e n - l - o n e 7_6 (141 mg, 0.68 mmol) i n t e t r a h y d r o f u r a n a t -20°C f o r 15 min, and a t room tem p e r a t u r e f o r 3 0 min. Normal workup, f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 60-72°C, 0.17 t o r r ) o f the crude o i l a f f o r d e d 138 mg (83%) o f the enone 8_1. A g l c a n a l y s i s (column A) showed the presence o f one component. T h i s m a t e r i a l e x h i b i t e d uv (MeOH) A : 233 nm (e= 15,200); i r max ( f i l m ) : 1685, 1558, 762 cm" 1; 1 H nmr (CDC1 3) 6: 0.25 ( s , 9H, s t a n n y l m e t h y l s , J 0 =56Hz), 2.23-2.35 (m, 2H, o n - r l -CH 2-C0-), 2.73-2.90 (m, 2H, -CH 2CH 2"CO-), 6.37 ( t , IH, - 114 -v i n y l p r o t o n , J=2.3Hz, J g n _ H = 3 3 H z ) . E x a c t mass c a l c d . f o r CgH 1 40Sn: 247.0145, found: 247.0143. b) R e a c t i o n o f Me 3SnCu•LiBr•SMe 2 94 w i t h 3 - I o d o - 2 - c y c l o p e n t e n - l - o n e 7 6 F o l l o w i n g the g e n e r a l p r o c e d u r e B o u t l i n e d above, 0.65 mmol o f the t r i m e t h y l s t a n n y l c o p p e r r e a g e n t 9_4 was a l l o w e d t o r e a c t w i t h 3 - i o d o - 2 - c y c l o p e n t e n - l - o n e 7_6 (104 mg, 0.50 mmol) i n t e t r a h y d r o f u r a n a t -48°C f o r 2h, -20°C f o r l h , and a t room temperature f o r l h . Normal workup, f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 65-71°C, 0.15 t o r r ) o f the r e s i d u a l o i l a f f o r d e d 98 mg (80%) o f 3 - t r i m e t h y l s t a n n y l -2 - c y c l o p e n t e n - l - o n e 8_1. The s p e c t r a l p r o p e r t i e s o f t h i s m a t e r i a l were i d e n t i c a l w i t h those r e p o r t e d e a r l i e r . P r e p a r a t i o n o f 3 - T r i - n - b u t y l s t a n n y l - 2 - c y c l o p e n t e n - l - o n e 82 SnBiA 82 ° F o l l o w i n g the g e n e r a l p r o c e d u r e C o u t l i n e d above, 0.55 mmol o f l i t h i u m p h e n y l t h i o ( t r i - n - b u t y l s t a n n y l ) c u p r a t e 73_ was a l l o w e d t o r e a c t w i t h 3 - i o d o - 2 - c y c l o p e n t e n - l - o n e 76 (104 mg, 0.50 mmol) i n t e t r a h y d r o f u r a n a t -20°C f o r 15 min, and a t room temperature f o r 3 0 min. Normal workup, f o l l o w e d by column chromatography o f the crude p r o d u c t and d i s t i l l a t i o n ( a i r - b a t h t e mperature 150-154°C, 0.2 t o r r ) o f the o i l o b t a i n e d from the a p p r o p r i a t e f r a c t i o n s , a f f o r d e d 141 mg (76%) o f the enone 8_2. An a n a l y t i c a l sample was o b t a i n e d by p r e p a r a t i v e t i c on s i l i c a g e l ( d e v e l o p i n g s o l v e n t : p e t r o l e u m e t h e r - e t h e r , 9:1). T h i s m a t e r i a l e x h i b i t e d uv (MeOH) X : 235 nm max (e= 12,100); i r ( f i l m ) : 1705, 1555 cm" 1; 1 H nmr (CDC1 3) 6: 0.76-1.18 (m, 15H, -Sn(CH 2CH 2CH 2CH 3) ), 1.18-1.72 (m, 12H, - S n ( C H 2 C H 2 C H 2 C H 3 ) 3 ) ; 2.24-2.39 (m, 2H, -CH -CO-), 2.76-2.96 (m, 2H, -CH 2CH 2"CO-), 6.40 ( t , IH, v i n y l p r o t o n , J=2Hz, J 0 =29Hz) . E x a c t mass c a l c d . f o r C, -.H-. o 0 S n : 372.1475; found: 372.1488. A n a l , c a l c d . f o r C ^ H ^ O S n : C 55.02, H 8.69; f o u n d : C 54.79, H 8.70. P r e p a r a t i o n o f 2 - M e t h y l - 3 - t r i m e t h y l s t a n n y l - 2 - c y c l o p e n t e n - l - o n e 83 SnMeo 83 0 a) R e a c t i o n o f L i t h i u m P h e n y l t h i o ( t r i m e t h y l s t a n n y l ) c u p r a t e 72  w i t h 2 - M e t h y l - 3 - i o d o - 2 - c y c l o p e n t e n - l - o n e 77 F o l l o w i n g the g e n e r a l p r o c e d u r e A o u t l i n e d above, 0.7 5 mmol of l i t h i u m p h e n y l t h i o ( t r i m e t h y l s t a n n y l ) c u p r a t e 7_2 was a l l o w e d t o r e a c t w i t h 2 - m e t h y l - 3 - i o d o - 2 - c y c l o p e n t e n - l - o n e - 116 -77 (151 mg, 0.68 mmol) i n t e t r a h y d r o f u r a n a t -20°C f o r 15 min, and a t room temperature f o r 30 min. Normal workup, f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h t e mperature 65-73°C, 0.2 t o r r ) o f the r e s i d u a l o i l a f f o r d e d 144 mg (82%) o f 2 - m e t h y l - 3 - t r i m e t h y l -s t a n n y l - 2 - c y c l o p e n t e n - l - o n e 83_. T i c and g l c a n a l y s e s ( s i l i c a g e l and column A, r e s p e c t i v e l y ) showed the presence o f one component. T h i s m a t e r i a l e x h i b i t e d uv (MeOH) ^ m a x : 24 2.5 nm (e= 15,800); i r ( f i l m ) : 1690, 1601, 765 cm" 1; 1 H nmr (CDC1.J 6: 0.26 ( s , 9H, s t a n n y l m e t h y l s , J 0 =56Hz), 1.83 ( t , 3H, v i n y l m e t h y l , J=2Hz), 2.28-2.40 (m, 2H, -CH^-CO-), 2.58-2.76 (m, 2H, -CH 2CH 2-CO-). E x a c t mass c a l c d . f o r C 9H l 6OSn: 260.0224; found: 260.0234. b) R e a c t i o n o f Me 3SnCu•LiBr•SMe 2 94 w i t h 2 - M e t h y l - 3 - i o d o - 2 - c y c l o p e n t e n - l - o n e 7_7_ To a c o l d (-48°C), s t i r r e d s o l u t i o n o f the t r i m e t h y l s t a n n y l -copper r e a g e n t 94_ (0.65 mmol) i n 5 mL o f anhydrous t e t r a h y d r o -f u r a n , under an atmosphere o f arg o n , was s e q u e n t i a l l y added, hexamethylphosphoramide (2 mL) and a s o l u t i o n (THF, ^ 1 mL) o f 2 - m e t h y l - 3 - i o d o - 2 - c y c l o p e n t e n - l - o n e 7_7 (111 mg, 0.50 mmol). The r e s u l t i n g r e d s o l u t i o n was s t i r r e d a t -48°C f o r 2h, -20°C f o r l h , and a t room temperature f o r l h . Normal work-up (as i n g e n e r a l p r o c e d u r e B; i n c l u d i n g s e v e r a l a d d i t i o n a l w a ter w a s h i n g s ) , f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 63-75°C, 0.2 t o r r ) o f t h e crud e p r o d u c t a f f o r d e d 105 mg (82%) of 2 - m e t h y l - 3 - t r i m e t h y l s t a n n y l - 2 - c y c l o p e n t e n - l - o n e 83. The - 117 -s p e c t r a l p r o p e r t i e s o f t h i s m a t e r i a l were i d e n t i c a l w i t h those r e p o r t e d e a r l i e r . P r e p a r a t i o n o f 2 - M e t h y l - 3 - t r i - n - b u t y l s t a n n y l - 2 - c y c l o p e n t e n - l -one 8 4 0 F o l l o w i n g t h e g e n e r a l p r o c e d u r e C o u t l i n e d above, 0.65 mmol of l i t h i u m p h e n y l t h i o ( t r i - n - b u t y l s t a n n y l ) c u p r a t e 7_3_ was a l l o w e d to r e a c t w i t h 2 - m e t h y l - 3 - i o d o - 2 - c y c l o p e n t e n - l - o n e 77_ (110 mg, 0.50 mmol) i n t e t r a h y d r o f u r a n a t -20°C f o r 15 min, and a t room temperature f o r 3 0 min. Normal workup, f o l l o w e d by column chromatography of the crude p r o d u c t and d i s t i l l a t i o n ( a i r - b a t h t e mperature 158-164°C, 0.2 t o r r ) o f the m a t e r i a l o b t a i n e d from the a p p r o p r i a t e f r a c t i o n s a f f o r d e d 152 mg (79%) o f the enone 84. T h i s m a t e r i a l e x h i b i t e d uv (MeOH) A — max 246.5 nm (e= 13,200); i r ( f i l m ) : 1702 cm" 1; 1H nmr (CDC1 3) 6: 0.70-1.18 (m, 15H, -Sn(CH 2CH 2CH 2CH 3) ), 1.18-1.67 (m, 12H, -Sn(CH 2CH 2CH 2CH 3) ), 1.84 ( t , 3H, v i n y l m e t h y l , J ^ 2 H z ) , 2.28-2.42 (m, 2H, -CHj-CO-) , 2.58-2.80 (m, 2H, -CH_2CH2-CO-) , E x a c t mass c a l c d . f o r C ^ H ^ O S n : 386.1632; fo u n d : 386.1609 A n a l , c a l c d . f o r C ^ H ^ O S n : C 56.13, H 8.90; found: C 56.37 , H 9. - 118 -P r e p a r a t i o n o f ( E - 2 - ( T r i m e t h y l s t a n n y l m e t h y l e n e ) c y c l o h e x a n o n e 85 85 a) R e a c t i o n o f L i t h i u m P h e n y l t h i o ( t r i m e t h y l s t a n n y l ) c u p r a t e  72 w i t h (E-2-Iodomethylenecyclohexanone 7_8 F o l l o w i n g the g e n e r a l p r o c e d u r e A o u t l i n e d above, 0.75 mmol of l i t h i u m p h e n y l t h i o ( t r i m e t h y l s t a n n y l ) c u p r a t e 7_2 was a l l o w e d t o r e a c t w i t h ( E -2-iodomethylenecyclohexanone 78_ (134 mg, 0.57 mmol) i n t e t r a h y d r o f u r a n a t -20°C f o r 15 min, and a t room temperature f o r 3 0 min. Normal workup a f f o r d e d a r e d o i l w h i c h was p u r i f i e d by p r e p a r a t i v e t i c on s i l i c a g e l ( d e v e l o p i n g s o l v e n t : p e t r o l e u m e t h e r - e t h e r , 9:1). D i s t i l l a t i o n o f the o i l thus o b t a i n e d a f f o r d e d 120 mg (77%) o f the enone 8_5. T i c and g l c a n a l y s e s ( s i l i c a g e l and column A, r e s p e c t i v e l y ) showed the p r e s e n c e o f one component. T h i s m a t e r i a l e x h i b i t e d uv (MeOH) A : 246 nm (e= 8,300); max i r ( f i l m ) : 1687, 1577, 775 cm" 1, 1 H nmr (CDC1 3) 6: 0.17 ( s , 9H, s t a n n y l m e t h y l s , J c =56Hz), 1.63-2.05 (m, 4H, -CH -CO-CH 0), 7.03 ( t , IH, v i n y l p r o t o n , J=2Hz, J _ =68Hz). — — ^ on—ti E x a c t mass c a l c d . f o r CgH^OSn (M + - 1 5 ) : 259.0145; fo u n d : 259.0142. - 119 -b) R e a c t i o n o f Me ?SnCu•LiBr•SMe 2 94 w i t h (E) -2-Iodomethylenecyclohexanone 7_8 To a c o l d (-48°C), s t i r r e d s o l u t i o n o f the t r i m e t h y l -s t a n n y l c o p p e r r e a g e n t 9_4 (0.65 mmol) i n 5 mL o f anhydrous t e t r a h y d r o f u r a n under an atmosphere o f arg o n , was added a s o l u t i o n (THF, ^ 1 mL) o f f r e s h l y d i s t i l l e d ( E ) - 2 - i o d o -m e t h ylenecyclohexanone 7_8_ (118 mg, 0.50 mmol). A f t e r the r e s u l t i n g m i x t u r e had been s t i r r e d a t -48°C f o r 2h, i t was t r e a t e d w i t h pH 8 s a t u r a t e d aqueous ammonium c h l o r i d e . Normal workup (as o u t l i n e d i n g e n e r a l p r o c e d u r e B ) , f o l l o w e d i m m e d i a t e l y by p r e p a r a t i v e t i c on s i l i c a g e l ( d e v e l o p i n g s o l v e n t : p e t r o l e u m e t h e r - e t h e r , 9:1), and d i s t i l l a t i o n ( a i r -b a t h t emperature 79-90°C, 0.17 t o r r ) o f the o i l thus o b t a i n e d a f f o r d e d 102 mg (75%) o f ( E ) - 2 - ( t r i m e t h y l s t a n n y l -methylene) cyclohexanone 8_5. The s p e c t r a l p r o p e r t i e s o f t h i s m a t e r i a l were i d e n t i c a l w i t h t h o s e r e p o r t e d e a r l i e r . P r e p a r a t i o n o f ( E j - 2 - ( T r i - n - b u t y l s t a n n y l m e t h y l e n e ) c y c l o h e x a n o n e 86 SnBu n 3 86 F o l l o w i n g the g e n e r a l p r o c e d u r e C o u t l i n e d above, 0.55 mmol o f l i t h i u m p h e n y l t h i o ( t r i - n - b u t y l s t a n n y l ) c u p r a t e 73-was - 120 -a l l o w e d t o r e a c t w i t h (E) - 2 - i o d o m e t h y l e n e c y c l o h e x a n o n e 78_ (118 mg, 0.5 mmol) i n t e t r a h y d r o f u r a n a t -20°C f o r 30 min, and a t room temperature f o r 3 0 min. Normal workup, f o l l o w e d by column chromatography o f the crude p r o d u c t on s i l i c a g e l and d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 160-171°C, 0.2 t o r r ) o f the o i l o b t a i n e d from the a p p r o p r i a t e f r a c t i o n s a f f o r d e d 136 mg (69%) o f the enone 8_6. T i c and g l c a n a l y s e s ( s i l i c a g e l and column A, r e s p e c t i v e l y ) showed the presence o f one component. T h i s m a t e r i a l e x h i b i t e d uv (MeOH) A : 250 nm c max (e= 7,400); i r ( f i l m ) : 1690, 1581 cm" 1; 1H nmr (CDC1 3) 6: 0.77-1.13 (m, 15H, -Sn(CH 2CH 2CH 2CH 3) ), 1.17-1.66 (m, 12H, -Sn(CH 2CH 2CH 2CH 3) ), 1.66-2.00 (m, 4H, -CH 2CH 2CH_ 2CH 2-), 2 . 38-2 . 68 (m, 4H, -CH_2-CO-CH2-) , 7.08 ( t , IH, v i n y l p r o t o n , J=2Hz, J =62Hz). E x a c t mass c a l c d . f o r C, nH o.0Sn: bn - n ±y j b 400.1788; found: 400.1763. P r e p a r a t i o n o f 3 - T r i m e t h y l s i l o x y - l - t r i - n - b u t y l s t a n n y l - l , 3 - c y c l o h e x a d i e n e 101 101 To a c o l d (-78 C ) , s t i r r e d s o l u t i o n o f l i t h i u m d i i s o p r o p y l a m i d e (3.3 mmol) i n 3 0 mL o f anhydrous t e t r a h y d r o -f u r a n , under a r g o n , was added, d r o p w i s e , a s o l u t i o n o f 3 - t r i - n - b u t y l s t a n n y l - 2 - c y c l o h e x e n - l - o n e 7_4 (1.15 g, 3.0 mmol) i n t e t r a h y d r o f u r a n (5 mL). A f t e r the a d d i t i o n was co m p l e t e , t h e r e a c t i o n m i x t u r e was a l l o w e d t o s t i r a t -78°C f o r l h , and a t 0°C f o r 30 min. The r e s u l t i n g y e l l o w s o l u t i o n was c o o l e d t o -78°C. A f r e s h l y p r e p a r e d and c e n t r i f u g e d m i x t u r e o f t r i m e t h y l s i l y l c h l o r i d e (0.50 mL, 3.9 mmol) and t r i e t h y l a m i n e (0.25 mL, 1.8 mmol) was added. The c o o l i n g b a t h was then removed and the r e s u l t i n g m i x t u r e was s t i r r e d f o r an a d d i t i o n a l p e r i o d o f l h . S a t u r -a t e d aqueous sodium b i c a r b o n a t e and e t h e r were added. The m i x t u r e was washed w i t h 5% (w/v) aqueous sodium b i c a r b o n a t e and b r i n e and d r i e d o v e r anhydrous magnesium s u l f a t e . Removal o f s o l v e n t , f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h t e mperature 140-148°C, 0.09 t o r r ) o f the r e s i d u a l o i l a f f o r d e d 1.28 g (93%) o f t h e e n o l s i l y l e t h e r 101. A g l c a n a l y s i s (column A) o f t h i s m a t e r i a l showed the p r e s e n c e of one magor component ( 97%) which e x h i b i t e d i r ( f i l m ) : 1637, 1250, 1195, 840 cm" 1; 1 H nmr (CDC1 3) <5 : 0.16 ( s , 9H, s i l y l m e t h y l s ) , 0.75-1.01 (m, 15H, -Sn (CH_ 2CH 2CH 2CH 3) 3 ) , 1.11-1.69 (m, 12H, - S n ( C H 2 C H 2 C H 2 C H 3 ) 3 ) , 2.03-2.19 (m, 4H, a l l y l i c methylene p r o t o n s ) , 4.86 (m, IH, -CH=C(OSiMe 3)), 5.83 (m,. IH, -CH=C(SnR 3), J S n _ H = 6 0 H z ) E x a c t mass c a l c d . f o r C 2 1 H 4 2 O S i S n : 458.2027; found 458.2012. - 122 -T r a n s m e t a l a t i o n of 3 - T r i m e t h y l s i l o x y - l - t r i - n - b u t y l s t a n n y l -1 , 3 - c y c l o h e x a d i e n e 101 102 103 To a c o l d (-90°C), s t i r r e d s o l u t i o n o f the e n o l s i l y l e t h e r 101 (229 mg, 0.5 mmol) i n 10 mL o f anhydrous t e t r a -h y d r o f u r a n , under an atmosphere of a r g o n , was added a s o l u t i o n o f n - b u t y l l i t h i u m i n hexane (0.35 mL, 0.55 mmol). The r e s u l t i n g m i x t u r e was s t i r r e d a t -90°C f o r 2h, warmed to 0°C, and s t i r r e d f o r an a d d i t i o n a l p e r i o d o f 30 min. The y e l l o w s o l u t i o n was t h e n c o o l e d t o -90°C, t r e a t e d w i t h a s o l u t i o n o f a c e t i c a c i d i n e t h e r (0.55 mL, 0.55 mmol), and s t i r r e d f o r s e v e r a l m i n u t e s . The m i x t u r e was a l l o w e d t o warm t o room t e m p e r a t u r e , washed w i t h s a t u r a t e d aqueous sodium b i c a r b o n a t e , and d r i e d o v er anhydrous magnesium s u l f a t e . Removal o f s o l v e n t , f o l l o w e d by d i s t i l l a t i o n ( a i r -b a t h temperature 60-130°C, 20 t o r r ) o f the r e s i d u e a f f o r d e d 68 mg o f a y e l l o w o i l . A g l c a n a l y s i s (column A) o f t h i s m a t e r i a l showed t h a t i t was composed o f the e n o l s i l y l e t h e r 102 and the ketone 103 i n a r a t i o o f ^1:5, r e s p e c t i v e l y . - 123 -Other minor u n i d e n t i f i e d p r o d u c t s were a l s o p r e s e n t . R e d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 69-80°C, 35 t o r r ) o f the p r o d u c t m i x t u r e a f f o r d e d 9 mg (11%) o f 3 - t r i m e t h y l -s i l o x y - l , 3 - c y c l o h e x a d i e n e 102 ( l i t . bp 56-58 C 6 t o r r ) . T h i s m a t e r i a l ( 98% pure by g l c a n a l y s i s , column A) e x h i b i t e d i r ( f i l m ) : 3050, 1643, 1592 cm" 1; 1 H nmr (CDClj) 6: 0.15 (s„ 9H, s i l y l m e t h y l s ) , 2.05-2.19 (m, 4H, a l l y l i c methylene p r o t o n s ) , 4.87 (m, IH, -CH=C(OSiMe 3)), 5.73 (m, 2H, -CH 2CH=CH-). E x a c t mass c a l c d . f o r C g H 1 6 O S i : 168.0970; f o u n d : 168.0973. The r e m a i n i n g s t i l l p o t r e s i d u e was p u r i f i e d by p r e p -a r a t i v e t i c on s i l i c a g e l ( d e v e l o p i n g s o l v e n t : p e t r o l e u m e t h e r - e t h e r , 9:1). D i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 110-123°C, 15 t o r r , l i t . 4 7 bp 90°C, 9.5 t o r r ) o f the o i l thus o b t a i n e d gave 49 mg (59%) o f 3 - t r i m e t h y l s i l y l - 2 -c y c l o h e x e n - l - o n e 103. T h i s m a t e r i a l (^96% pure by g l c a n a l y s i s , column A) e x h i b i t e d i r ( f i l m ) : 1675, 1595, 840 cm 1H nmr (CDC1 3) <S : 0.10 ( s , 9H, s i l y l m e t h y l s ) , 1.84-2.18 (m, 2H, -CH 2CH 2CH 2-) , 2.18-2.54 (m, 4H, -CH2CH2CH_2-) , 6.22 ( t , IH, v i n y l p r o t o n , J=2Hz). E x a c t mass c a l c d . f o r C 9 H 1 6 O S i : 168.0970, fo u n d : 168.0985. - 124 -P r e p a r a t i o n o f 3 - t e r t - B u t y l d i m e t h y l s i l o x y - 1 - t r i - n -b u t y l s t a n n y l - 1 , 3 - c y c l o h e x a d i e n e 108 0SiMe 2Bu t SnBu n 3 108 To a c o l d (-78°C), s t i r r e d s o l u t i o n o f the l i t h i u m e n o l a t e o f ketone 7_4 (3.0 mmol, p r e p a r e d as o u t l i n e d above) i n anhydrous t e t r a h y d r o f u r a n (20 mL), under an atmosphere o f a r g o n , was added a s o l u t i o n o f f r e s h l y s u b l i m e d t e r t - b u t y l d i m e t h y l s i l y l c h l o r i d e (0.68 g, 4.5 mmol) i n anhydrous hexamethylphosphoramide (2 mL). The c o o l i n g b a t h was the n removed and t h e r e a c t i o n m i x t u r e was s t i r r e d f o r an a d d i t i o n a l p e r i o d o f 2h. S a t u r a t e d aqueous sodium b i c a r b o n a t e and e t h e r were added. The e t h e r l a y e r was s e p a r a t e d , washed w i t h 5% (w/v) aqueous sodium b i c a r b o n a t e and w a t e r , and d r i e d o ver anhydrous magnesium s u l f a t e . Removal o f the s o l v e n t f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 147-156°C, 0.09 t o r r ) o f the r e s i d u a l o i l a f f o r d e d 1.41 g (94%) o f the e n o l s i l y l e t h e r 108. T h i s m a t e r i a l e x h i b i t e d uv (MeOH) A : 277 nm max ( e = 6,900); i r ( f i l m ) : 1640, 1250, 1195, 840 cm" 1; 1 H nmr (CDC1 3) 6: 0.08 ( s , 6H, s i l y l m e t h y l s ) , 0.89 ( s , 9H, t e r t - b u t y l m e t h y l s ) , 0.74-1.02 (m, 15H, -Sn (CH 2CH 2CH 2CH_ 3) 3 ) , 1.06-1.62 (m, 12H, -Sn(CH 2CH 2CH 2CH 3) ), 2.02-2.18 (m, 4H, a l l y l i c methylene p r o t o n s ) , 4.86 (m, IH, -CH=C(OSiMe 3)), 5.85 (m, IH, -CH=C(SnR 3), J S n _ H = 6 0 H z ) . E x a c t mass c a l c d . f o r C 2 4 H 4 g O S i S n : C 57.72, H 9.69; found: C 58.00, H 9.70. P r e p a r a t i o n o f 3 - t e r t - B u t y l d i m e t h y l s i l o x y - l - t r i m e t h y l -s t a n n y l - 1 , 3 - c y c l o h e x a d i e n e 110 0SiMe 2Bu t To a c o l d (-78°C), s t i r r e d s o l u t i o n o f l i t h i u m d i i s o p r o p y l a m i d e (3.3 mmol) i n 15 mL o f anhydrous t e t r a -h y d r o f u r a n , under an atmosphere o r a r g o n , was added, d r o p -w i s e , a s o l u t i o n o f 3 - t r i m e t h y l s t a n n y l - 2 - c y c l o h e x e n - l - o n e 70 (0.78 g, 3.0 mmol) i n t e t r a h y d r o f u r a n (5 mL). A f t e r the a d d i t i o n was c o m p l e t e , the r e a c t i o n m i x t u r e was a l l o w e d t o s t i r a t -78°C f o r l h and a t 0°C f o r 30 min. The r e s u l t -i n g y e l l o w s o l u t i o n was c o o l e d t o -78°C, and a s o l u t i o n o f f r e s h l y s u b l i m e d t e r t - b u t y l d i m e t h y l s i l y l c h l o r i d e (0.68 g, 4.5 mmol) i n anhydrous hexamethylphosphoramide (2 mL) was added. The c o o l i n g b a t h was removed and the r e a c t i o n m i x t u r e was s t i r r e d f o r an a d d i t i o n a l p e r i o d o f 2h. S a t u r a t e d aqueous sodium b i c a r b o n a t e and e t h e r were added. The m i x t u r e was washed w i t h 5% (w/v) aqueous sodium b i c a r b -onate and water and d r i e d o ver anhydrous magnesium s u l f a t e . Removal o f s o l v e n t , f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h t e mperature 80-93°C, 0.1 t o r r ) o f the r e s i d u a l o i l a f f o r d e d 1.07 g (96%) o f the e n o l s i l y l e t h e r 110. A g l c a n a l y s i s (column A) showed the pr e s e n c e o f one component. T h i s m a t e r i a l e x h i b i t e d i r ( f i l m ) : 1642, 1584, 840, 770 cm" 1; 1H nmr (CDCl-j) 6: 0.11 ( s , 15H, s i l y l and s t a n n y l m e t h y l s , J g n _ H = 5 4 H z ) , 0.90 ( s , 9H, t e r t - b u t y l m e t h y l s ) , 1.06-1.20 (m, 4H, a l l y l i c methylene p r o t o n s ) , 4.87 (m, IH, -CH=C(OSis)) 5.87 (m, IH, -CH=C(SnR_)). E x a c t mass c a l c d . f o r C l cH o„0SiSn — J — l b JU 374.1084; found 374.1087. G e n e r a l P r o c e d u r e D: P r e p a r a t i o n o f l - L i t h i o - 3 - t e r t -b u t y l d i m e t h y l s i l o x y - 1 , 3 - c y c l o h e x a d i e n e 111 and i t s r e a c t i o n w i t h E e l e c t r o p h i l e s . To a c o l d (-78°C), s t i r r e d s o l u t i o n o f e i t h e r the e n o l s i l y l e t h e r 108 or 110 (0.40 mmol 108, 0.27 mmol 110) i n anhydrous t e t r a h y d r o f u r a n (10 mL and 5 mL f o r 108 and 110, - 127 -r e s p e c t i v e l y ) , under an atmosphere o r a r g o n , was added a s o l u t i o n o f the a p p r o p r i a t e a l k y l l i t h i u m r e a g e n t (1.1-1.2 e q u i v a l e n t s ) . The r e s u l t i n g m i x t u r e was s t i r r e d a t -78°C f o r a p e r i o d o f l h . A y e l l o w s o l u t i o n o f the v i n y l l i t h i u m i n t e r m e d i a t e 111 r e s u l t e d . A s o l u t i o n o f the a p p r o p r i a t e e l e c t r o p h i l e (1.3 e q u i v -a l e n t s ) i n anhydrous t e t r a h y d r o f u r a n (^0.4 mL) was added.* When t h e e l e c t r o p h i l e was an a l k y l h a l i d e , t h e r e a c t i o n m i x t u r e was s t i r r e d a t -7 8°C f o r l h , warmed t o room temp-e r a t u r e o ver a p e r i o d o f l h , and then quenched w i t h s a t -u r a t e d aqueous sodium b i c a r b o n a t e (^0.2 mL). Wi t h c a r b o n y l e l e c t r o p h i l e s , t he r e a c t i o n m i x t u r e was s t i r r e d a t -78°C f o r l h , and t r e a t e d a t t h i s t e m p e r a t u r e w i t h s a t u r a t e d aqueous sodium c a r b o n a t e (^0.2 mL). The r e s u l t i n g m i x t u r e s were i m m e d i a t e l y d i l u t e d w i t h e t h e r , washed w i t h s a t u r a t e d aqueous sodium b i c a r b o n a t e , and d r i e d o v e r anhydrous magnesium s u l f a t e . Removal o f the s o l v e n t a f f o r d e d a y e l l o w o i l . When 108 was employed as t h e p r e c u r s o r t o the v i n y l l i t h i u m r e a g e n t 111, the p r o d u c t and t e t r a - n - b u t y l t i n were s e p a r a t e d by c a r e f u l d i s t i l l a t i o n ( a i r - b a t h ) . When 110 was employed as the p r e c u r s o r t o 111 the r e a c t i o n p r o d u c t was p u r i f i e d by a s i m p l e d i s t i l l a t i o n ( a i r - b a t h ) . * Cyclohexanone and dimethyl(methylene)ammonium i o d i d e were i n t r o d u c e d w i t h o u t the a i d o f s o l v e n t . - 128 -P r e p a r a t i o n o f l - B r o m o - 2 - ( 2 - c y c l o p e n t y l ) e t h a n e To a m i x t u r e o f t r i p h e n y l p h o s p h i n e (5.77 g, 22.0 mmol) i n 50 mL o f anhydrous a c e t o n i t r i l e a t 0°C under a r g o n , was added bromine (1.10 mL, 21.5 mmol). The r e s u l t i n g m i x t u r e was s t i r r e d f o r 15 min t o a f f o r d a w h i t e s u s p e n s i o n o f 77 t r i p h e n y l p h o s p h i n e d i b r o m i d e . T r i e t h y l a m i n e (4.04 g, 40.0 mmol) and a s o l u t i o n o f 2 - ( 2 - c y c l o p e n t e n y l ) e t h a n o l * (2.24 g, 20.0 mmol) i n a c e t o n i t r i l e (^5 mL) were added. The r e a c t i o n m i x t u r e was s t i r r e d a t room tem p e r a t u r e f o r 30 min. L i g h t p e t r o l e u m e t h e r (^200 mL) was added and the r e s u l t i n g m i x t u r e was f i l t e r e d t h r o u g h a s h o r t column o f s i l i c a g e l . The column was f l u s h e d w i t h a f u r t h e r 200 mL of l i g h t p e t r o l e u m e t h e r and the e l u a n t was combined. Removal o f the s o l v e n t (under a t m o s p h e r i c p r e s s u r e ) f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 95-100°C, 35 t o r r ) o f the r e s i d u a l o i l a f f o r d e d 2.12 g (61%) o f l-bromo-2-( 2 - c y c l o p e n t y l ) e t h a n e . A g l c a n a l y s i s (column A) showed * T h i s compound can be p r e p a r e d by the l i t h i u m aluminum h y d r i d e r e d u c t i o n o f ( 2 - c y c l o p e n t e n y l ) a c e t i c a c i d . 78 - 129 -the p r e s e n c e o f one component. T h i s m a t e r i a l e x h i b i t e d i r ( f i l m ) : 3030, 720 cm" 1; 1 H nmr (60 MHz) (CDC1 3) 6: 1 . 0 6 -1.66 (m, I H ) , 1.66-2.50 (m, 5H), 2.50-3.00 (m, IH, t e r t i a r y p r o t o n ) , 3.29 ( t , 2H, -CH_2Br, J=7Hz), 5.47-5.83 (m, 2H, 79 o l e f i n i c p r o t o n s ) . E x a c t mass c a l c d . f o r C-yH^ B r : 174.0044; found: 174.0037. 7 9 P r e p a r a t i o n o f ( 2 - C y c l o p e n t e n y l ) e t h a n o l To a c o l d (0°C), s t i r r e d s u s p e n s i o n o f p y r i d i n i u m c h l o r o c h r o m a t e (6.47 g, 30 mmol) i n 50 mL o f anhydrous d i c h l o r o m e t h a n e , under a r g o n , was added a s o l u t i o n ( C H 2 C l 2 , 10 mL) o f 2 - ( 2 - c y c l o p e n t e n y l ) e t h a n o l (2.24 g, 20 mmol). The c o o l i n g b a t h was removed and the r e a c t i o n m i x t u r e was s t i r r e d f o r an a d d i t i o n a l 3h. E t h e r (^200 mL) was added and the r e s u l t a n t m i x t u r e was f i l t e r e d t h r o u g h a s h o r t column o f f l o r i s i l (^50 g ) . The column was f u r t h e r e l u t e d w i t h an a d d i t i o n a l volume (^100 mL) o f e t h e r and the e l u a n t was combined. Removal o f the s o l v e n t , ( d i s t i l l a t i o n under a t m o s p h e r i c p r e s s u r e ) f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 80-92°C, 30 t o r r ; l i t . 7 9 bp 51-52°C, 19 t o r r ) o f the r e s i d u a l o i l a f f o r d e d 1.70 g (77%) o f ( 2 - c y c l o p e n t e n y l ) - 130 -e t h a n a l . A g l c a n a l y s i s (column A) showed the p r e s e n c e o f one component. T h i s m a t e r i a l e x h i b i t e d i r ( f i l m ) : 3045, 2710, 1720 cm" 1; 1 H nmr (60 MHz) (CDC1 3) 6: 1.10-1.85 (m, I H ) , 1.90-2.60 (m, 5H), 2.83-3.33 (m, IH, t e r t i a r y p r o t o n ) , 5.43-5.83 (m, 2H, o l e f i n i c p r o t o n s ) , 9.76 ( t , IH, -CHO, J ^ 2 H z ) . P r e p a r a t i o n o f 3 - t e r t - B u t y l d i m e t h y l s i l o x y - l , 3 - c y c l o h e x a d i e n e 109 0SiMe 2Bu t 109 a) From the E n o l S i l y l E t h e r 108 F o l l o w i n g the g e n e r a l p r o c e d u r e D o u t l i n e d above, 0.4 mmol (200 mg) o f the e n o l s i l y l e t h e r 108 was a l l o w e d t o r e a c t w i t h n - b u t y l l i t h i u m (0.44 mmol) i n t e t r a h y d r o f u r a n (10 mL) a t -78°C f o r 90 min and a t 0°C f o r 30 min. The r e s u l t i n g y e l l o w s o l u t i o n was c o o l e d t o -78°C and t r e a t e d w i t h a s o l u t i o n o f a c e t i c a c i d i n e t h e r (0.44 mL, 0.44 mmol). Normal workup, f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 107-120°C, 20 t o r r ) o f the r e s i d u a l o i l gave 73 mg (87%) o f the e n o l s i l y l e t h e r 109 (under t h e s e c o n d i t i o n s the contam-i n a n t t e t r a - n - b u t y l t i n remained i n the s t i l l p o t ) . A g l c a n a l y s i s (column B) showed the presence o f one component. T h i s m a t e r i a l e x h i b i t e d i r ( f i l m ) : 3055, 1643, 1590 cm 1 ; 1H nmr (CDC1 3) 6: 0.08 ( s , 6H, s i l y l m e t h y l s ) , 0.89 ( s , 9H, t e r t - b u t y l m e t h y l s ) , 2.02-2.16 (m, 4H, a l l y l i c methylene p r o t o n s ) , 4.87 (m, IH, -CH=C(OSiR 3)), 5.78 (m, 2H, -CH=CH-). E x a c t mass c a l c d . f o r C ^ H ^ O S i : 210.1440; found: 210.1440. b) From t h e E n o l S i l y l E t h e r 110 F o l l o w i n g the g e n e r a l p r o c e d u r e D o u t l i n e d above, 0.27 mmol (100 mg) o f t h e e n o l s i l y l e t h e r 110 was a l l o w e d t o r e a c t w i t h m e t h y l l i t h i u m (0.3 mmol) i n t e t r a h y d r o f u r a n (5 mL) a t -78°C f o r l h , and the r e s u l t i n g s o l u t i o n was t r e a t e d w i t h a s o l u t i o n o f a c e t i c a c i d i n e t h e r (0.3 mL, 0.3 mmol). Normal workup, f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 105-115°C, 20 t o r r ) o f the r e s i d u a l o i l gave 47 mg (84%) o f 3 - t e r t - b u t y l d i m e t h y l s i l o x y - l , 3 - c y c l o h e x a d i e n e 109. The s p e c t r a l p r o p e r t i e s o f t h i s m a t e r i a l were i d e n t i c a l w i t h t h o s e d e s c r i b e d e a r l i e r . P r e p a r a t i o n o f l - M e t h y l - 3 - t e r t - b u t y l d i m e t h y l s i l o x y - l , 3 - c y c l o h e x a d i e n e 113 113 - 132 -F o l l o w i n g t h e g e n e r a l p r o c e d u r e D o u t l i n e d above, 0.4 mmol o f the v i n y l l i t h i u m 111 (prepared from r e a c t i o n o f 108 w i t h n - b u t y l i t h i u m ) was a l l o w e d t o r e a c t w i t h iodomethane (32 yL, 0.52 mmol) i n t e t r a h y d r o f u r a n (10 mL) a t -78°C f o r l h , and a t room temp e r a t u r e f o r l h . Normal workup, f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 40-65°C, 0.05 t o r r , r e c e i v e r c o o l e d t o -78°C) o f the r e s i d u a l o i l a f f o r d e d 77 mg (86%) o f t h e e n o l s i l y l e t h e r 113 (under these c o n d i t i o n s the c o n t a m i n a n t t e t r a - n - b u t y l t i n remained i n the s t i l l p o t ) . A g l c a n a l y s i s (column B) showed the p r e s e n c e o f one component. T h i s m a t e r i a l e x h i b i t e d i r ( f i l m ) : 3055, 1660, 1615 cm" 1; 1 H nmr (CDC1 3) 6: 0.08 ( s , 6H, s i l y l m e t h y l s ) , 0.88 ( s , 9H, t e r t - b u t y l m e t h y l s ) , 1.76 (broad s, 3H, v i n y l m e t h y l ) , 1.88-2.30 (m, 4H, a l l y l i c m ethylene p r o t o n s ) , 4.72 (m, IH, -CH=C(OSiR 3)), 6.44 (m, IH, -CH=C(Me)-). E x a c t mass c a l c d . f o r C 1 3 H 2 4 O S i : 224.1596; found: 224.1587. P r e p a r a t i o n o f l - n - B u t y l - 3 - t e r t - b u t y l d i m e t h y l s i l o x y - l , 3 -c y c l o h e x a d i e n e 114 114 - 133 -F o l l o w i n g the g e n e r a l p r o c e d u r e D o u t l i n e d above, 0.27 mmol o f the v i n y l l i t h i u m 111 (prepared from the r e a c t i o n o f 110 w i t h m e t h y l l i t h i u m ) was a l l o w e d t o r e a c t w i t h 1-bromobutane (38 pL, 0.35 mmol) i n t e t r a h y d r o f u r a n (5 mL) a t -78°C f o r l h , and a t room temperature f o r l h . Normal workup, f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 70-76°C, 0.07 t o r r ) o f t h e r e s i d u a l o i l a f f o r d e d 51 mg (72%) o f t h e e n o l s i l y l e t h e r 114. A g l c a n a l y s i s (column B) o f t h i s m a t e r i a l showed the p r e s e n c e o f one component. T h i s m a t e r i a l e x h i b i t e d i r ( f i l m ) : 3070, 1660, 1615 cm" 1; 1 H nmr (CDC1 3) 6: 0.09 ( s , 6H, s i l y l m e t h y l s ) , 0.89 ( s , 9H t e r t - b u t y l m e t h y l s ) , 0.85-0.99 (m, 3H, t e r m i n a l m e t h y l ) , 1.23-1.51 (m, 4H, non-a l l y l i c methylene p r o t o n s ) , 1.97-2.19 (m, 6H, a l l y l i c methylene p r o t o n s ) , 4.73 (m, IH, -CH=C(OSir ) - ) , 5.43 (m, IH, -CH=C(Bu)-). E x a c t mass c a l c d . f o r C,,H-..OSi: 266.2065; found: 266.2062. 16 30 P r e p a r a t i o n o f 3 - n - B u t y l - 2 - c y c l o h e x e n - l - o n e 124 F o l l o w i n g the g e n e r a l p r o c e d u r e D o u t l i n e d above, 0.4 mmol o f the v i n y l l i t h i u m 111 (prepared by r e a c t i o n o f 108 w i t h n - b u t y l l i t h i u m ) was a l l o w e d t o r e a c t 124 w i t h 1-bromobutane (57 yL, 0.52 mmol) i n t e t r a h y d r o f u r a n a t -7 8°C f o r l h , and a t room t e m p e r a t u r e f o r l h . Normal workup a f f o r d e d a y e l l o w o i l which was d i s s o l v e d i n t e t r a h y d r o f u r a n (3 mL) and t r e a t e d w i t h IN aqueous h y d r o -c h l o r i c a c i d (0.3 mL). A f t e r the r e s u l t a n t m i x t u r e had been s t i r r e d a t room temperature f o r l h , i t was d i l u t e d w i t h e t h e r (^30 mL), washed w i t h 5% (w/v) aqueous sodium b i c a r b o n a t e , and d r i e d o ver anhydrous magnesium s u l f a t e . Removal o f the s o l v e n t a f f o r d e d a y e l l o w o i l w h i c h was p u r i f i e d by p r e p a r a t i v e t i c on s i l i c a g e l ( d e v e l o p i n g s o l v e n t : p e t r o l e u m e t h e r - e t h e r , 8:2). D i s t i l l a t i o n ( a i r -b a t h t e m p e r a t u r e 125-136°C, 20 t o r r ; l i t . 4 9 bp 83-84°C, 1.0 t o r r ) o f the o i l thus o b t a i n e d a f f o r d e d 41 mg (67%) o f the enone 124. A g l c a n a l y s i s (column A) showed the presence o f one component. T h i s m a t e r i a l e x h i b i t e d i r ( f i l m ) : 1672, 1622 cm" 1; 1 H nmr (CDCl-j) 6 : 0. 83-1. 05 (m, 3H, t e r m i n a l m e t h y l ) , 1.17-1.63 (m, 4H), 1.87-2.47 (m, 8H), 5.92 (m, IH, v i n y l p r o t o n ) . E x a c t mass c a l c d . f o r c i _ o H ] _ 6 0 : 152.1201; found: 152.1199. P r e p a r a t i o n o f 1- 2 - ( 2 - c y c l o p e n t e n y l ) e t h y l - 3 - t e r t -b u t y l d i m e t h y l s i l o x y - 1 , 3 - c y c l o h e x a d i e n e 115 0SiMeoBu 115 F o l l o w i n g t h e g e n e r a l p r o c e d u r e D o u t l i n e d above, 0.4 mmol o f the v i n y l l i t h i u m 111 (prepared by r e a c t i o n o f the e n o l s i l y l e t h e r 108 w i t h m e t h y l l i t h i u m , -78°C, l h ) was a l l o w e d t o r e a c t w i t h l - b r o m o - 2 - ( 2 - c y c l o p e n t e n y l ) e t h a n e (91 mg, 0.52 mmol) i n t e t r a h y d r o f u r a n a t -78°C f o r l h , and room t e m p e r a t u r e f o r l h . Normal workup, f o l l o w e d by removal o f m e t h y l t r i - n - b u t y l t i n and d i s t i l l a t i o n ( a i r -b a t h t e m p e r a t u r e 92-99°C, 0.05 t o r r ) o f the r e s i d u a l o i l a f f o r d e d 88 mg (72%) o f the e n o l s i l y l e t h e r 115. A g l c a n a l y s i s (column B) showed the p r e s e n c e o f one component. T h i s m a t e r i a l e x h i b i t e d i r ( f i l m ) : 3050, 1655, 1610 cm" 1; 1 H nmr (CDC1 3) <5 : 0.08 ( s , 6H, s i l y l m e t h y l s ) , 0.89 ( s , 9H t e r t - b u t y l m e t h y l s ) , 1.02-1.62 (m, 3H), 1.90-2.44 (m, 9H) , 2.44-2.76 (m, IH, a l l y l i c t e r t i a r y p r o t o n ) , 4.74 (m, IH, -CH=C(OSiR 3)-), 5.44 (m, IH, -CH=CR-), 5.70 (m, 2H, c y c l o p e n t e n y l v i n y l p r o t o n s ) . E x a c t mass c a l c d . f o r C 1 9 H 3 2 O S i : 3 0 4 - 2 2 2 3 ' * fou n d : 304.2216. - 136 -P r e p a r a t i o n o f 1-(4-Bromobutyl and 4 - C h l o r o b u t y l ) - 3 -t e r t - b u t y l d i m e t h y l s i l o x y - 1 , 3 - c y c l o h e x a d i e n e 116 and 117 116 X=Br 117 X=C1 F o l l o w i n g the g e n e r a l p r o c e d u r e D o u t l i n e d above 0.4 mmol of the v i n y l l i t h i u m 111 (prepared by the r e a c t i o n o f 108 w i t h m e t h y l l i t h i u m , -78°C, l h ) was a l l o w e d t o r e a c t w i t h l - b r o m o - 4 - c h l o r o b u t a n e (60 u L , 0.52 mmol) i n t e t r a -h y d r o f u r a n (10 mL) a t -78°C f o r l h , and room temperature f o r l h . Normal workup, f o l l o w e d by removal o f m e t h y l t r i -n - b u t y l t i n and d i s t i l l a t i o n ( a i r - b a t h t emperature 100-125°C, 0.05 t o r r ) o f the r e s i d u a l o i l a f f o r d e d 96 mg (78%) o f a y e l l o w o i l . An "^ H nmr a n a l y s i s showed t h a t t h i s m a t e r i a l was composed o f a m i x t u r e o f the e n o l s i l y l e t h e r s 116 and 117 i n a r a t i o o f 13:87. T h i s m a t e r i a l e x h i b i t e d i r ( f i l m ) : 3055, 1655, 1610 cm" 1; 1 H nmr (CDC1 3) 6 : 0.08 (s , 6H, s i l y l m e t h y l s ) , 0.89 ( s , 9H, t e r t - b u t y l m e t h y l s ) , 1.42-1.94 (m, 4H, -CH 2CH 2CH 2CH 2-), 1.94-2.32 (m, 6H, a l l y l i c m ethylene p r o t o n s ) , 3.40 and 3.52 ( t , t , 2H, -CH 2Br and -CH^Cl, J=6Hz f o r e a c h ) , 4.75 (m, IH, -CH=C10SiR 3)-), 5.44 (m, IH, -CH=CR-). E x a c t mass c a l c d . f o r C, CH„ o0Si 3 5C1: — l o 2.5 79 294-1207 ; found: 294-1203 . E x a c t mass c a l c d . f o r C ^ H ^ O S i B r : 338.0702; found: 338.0697. - 137 -P r e p a r a t i o n o f 1 - ( 1 - H y d r o x y b e n z y l ) - 3 - t e r t - b u t y l d i m e t h y l s i l o x y - 1 , 3 - c y c l o h e x a d i e n e 118 OSiMeoBu1 118 F o l l o w i n g the g e n e r a l p r o c e d u r e D o u t l i n e d above, 0.4 mmol o f the v i n y l l i t h i u m 111 (prepared by r e a c t i o n o f 108 w i t h n - b u t y l l i t h i u m ) was a l l o w e d t o r e a c t w i t h benzaldehyde (55 mg, 0.52 mmol) i n t e t r a h y d r o f u r a n (10 mL) a t -78°C f o r l h . Normal workup, f o l l o w e d by removal o f t e t r a - n - b u t y l t i n and d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 129-140°C, 0.06 t o r r ) o f the r e s i d u a l o i l a f f o r d e d 127 mg (90%) o f the e n o l s i l y l e t h e r 118. A g l c a n a l y s i s (column B) showed the p r e s e n c e of one component. T h i s m a t e r i a l e x h i b i t e d i r ( f i l m ) : 3410, 1635, 1608 cm" 1; 1 H nmr (CDC1 3) 6: 0.08 ( s , 6H, s i l y l m e t h y l s ) , 0.89 ( s , I H , t e r t - b u t y l m e t h y l s ) , 1.73-2.31 (m 5H, -CH_2CH2-, -OH), 4.79 (m, IH, -CH=C (OSiR 3) -) , 5.13 (m, IH, -CHOH), 5.84 (m, IH, -CH=CR-). E x a c t mass c a l c d . f o r C 1 9 H 2 8 0 2 S i : 316.1859; found: 316.1861. - 138 -P r e p a r a t i o n o f 1 - ( 1 - H y d r o x y h e x y l ) - 3 - t e r t -b u t y l d i m e t h y l s i l o x y - 1 , 3 - c y c l o h e x a d i e n e 119 F o l l o w i n g the g e n e r a l p r o c e d u r e D o u t l i n e d above, 0.27 mmol o f the v i n y l l i t h i u m r e a g e n t 111 (pr e p a r e d by r e a c t i o n o f 110 w i t h m e t h y l l i t h i u m ) was a l l o w e d t o r e a c t w i t h h e x a n a l (35 mg, 0.35 mmol) i n t e t r a h y d r o f u r a n (5 mL) a t -78°C f o r l h . Normal workup, f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 135-140°C, 0.18 t o r r ) o f the r e s i d u a l o i l a f f o r d e d 60 mg (71%) o f t h e e n o l s i l y l e t h e r 119. A g l c a n a l y s i s (column A) showed t h e p r e s e n c e o f one component. T h i s m a t e r i a l e x h i b i t e d i r ( f i l m ) : 3400, 1662, 1625 cm" 1; 1 H nmr (CDC1 3) <5: 0.08 ( s , 6H, s i l y l m e t h y l s ) , 0.88 ( s , 9H, t e r t - b u t y l m e t h y l s ) , 0.76-1.00 (m, 3H, t e r m i n a l m e t h y l ) , 1.14-1.72 (broad u n r e s o l v e d s i g n a l , 9H), 1.92-2.20 (m, 4H, a l l y l i c methylene p r o t o n s ) , 4.08 (broad t , IH, -CHOH, J=6Hz), 4.81 (m, IH, -CH=C(OSiR 3)-), 5.63 (m, IH, -CH=CR-). E x a c t  mass c a l c d . f o r C 1 8 H 3 4 C > 2 S i : 310.2328; found: 310.2334. - 139 -P r e p a r a t i o n o f 1 - ( 1 - H y d r o x y c y c l o h e x y l ) - 3 -t e r t - b u t y l d i m e t h y l s i l o x y - 1 , 3 - c y c l o h e x a d i e n e 120 120 a) From the E n o l S i l y l E t h e r 108 F o l l o w i n g the g e n e r a l p r o c e d u r e D o u t l i n e d above, 0.4 mmol o f the v i n y l l i t h i u m 111 (prepared by r e a c t i o n o f 108 w i t h n - b u t y l l i t h i u m ) was a l l o w e d t o r e a c t w i t h c y c l o h e x a n o n e (51 mg, 0.52 mmol) i n t e t r a h y d r o f u r a n a t -78°C f o r l h . Normal workup, f o l l o w e d by removal o f t e t r a - n - b u t y l t i n and d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 120-125°C, 0.04 t o r r ) o f the r e s i d u a l o i l a f f o r d e d 112 mg (91%) o f the e n o l s i l y l e t h e r 120. A g l c a n a l y s i s (column B) showed the p r e s e n c e o f one component. T h i s m a t e r i a l e x h i b i t e d uv (MeOH) A M : 268 nm (e= 5,250); i r ( f i l m ) : 3420, 1653, 1610 c m _ 1 ; 1H nmr (CDC1 3) <5 : 0.07 ( s , 6H, s i l y l m e t h y l s ) , 0.88 ( s , 9H, t e r t - b u t y l m e t h y l s ) , 1.22 ( s , IH, -OH), 1.48-1.64 (broad u n r e s o l v e d s i g n a l , 10H, c y c l o h e x y l methylene p r o t o n s ) , 4.82 (m, IH, -CH=C(OSiR 3)-), 5.74 (m, IH, -CH=CR-). E x a c t mass c a l c d . f o r C 1 8 H 3 2 0 2 S i : 308.2171; found: 308.2174. - 140 -b) From the Enol S i l y l Ether 110 Following the general procedure D outlined above, 0.27 mmol of the v i n y l l i t h i u m 111 (prepared by the reaction of 110 with methyllithium) was allowed to react with cyclo-hexanone (34 mg, 0.35 mmol) i n tetrahydrofuran at -78°C for l h . Normal workup, followed by d i s t i l l a t i o n (air-bath temperature 127-135°C, 0.07 torr) of the residue afforded 76 mg (92%) of the enol s i l y l ether 120. The spectral properties of this material were i d e n t i c a l with those reported e a r l i e r . Preparation of 1-(1-Hydroxycyclopentyl)-3-tert-butyldimethylsiloxy-1,3-cyclohexadiene 121 Following the general procedure D outlined above, 0.4 mmol of the v i n y l l i t h i u m 111 (prepared by reaction of 108 with n-butyllithium) was allowed to react with cyclopentanone (44 mg, 0.52 mmol) i n tetrahydrofuran at -78°C for l h . Normal workup, followed by d i s t i l l a t i o n (air-bath temperature 110-115°C, 0.04 torr) of the residual o i l gave 95 mg (81%) of the enol s i l y l ether 121. A glc analysis (column B) showed - 141 -the p r e s e n c e o f one component. T h i s m a t e r i a l e x h i b i t e d i r 6: 0.08 ( s , 6H, s i l y l m e t h y l s ) , 0.88 ( s , 9H, t e r t - b u t y l m e t h y l s ) , 1.26 ( s , IH, -OH), 1.50-1.92 (broad u n r e s o l v e d s i g n a l , 8H, c y c l o p e n t y l methylene p r o t o n s ) , 2.08-2.18 (m, 4H, a l l y l i c methylene p r o t o n s ) , 4.81 (m, IH, -CH=C(OSiR 3)-), 5.74 (m, IH, -CH=CR-) . E x a c t mass c a l c d . f o r C ^ H ^ O ^ i : 294.2014; found: 294.2018. b) From the E n o l S i l y l E t h e r 110 F o l l o w i n g the g e n e r a l p r o c e d u r e D o u t l i n e d above, 0.27 mmol of the v i n y l l i t h i u m r e a g e n t 111 (pre p a r e d by r e a c t i o n o f 110 w i t h m e t h y l l i t h i u m ) was a l l o w e d t o r e a c t w i t h c y c l o p e n t a n o n e (30 mg, 0.35 mmol) i n t e t r a h y d r o f u r a n a t -78°C f o r l h . Normal workup, f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 118-126°C, 0.10 t o r r ) o f the r e s i d u e a f f o r d e d 69 mg (87%) o f the e n o l s i l y l e t h e r 121. The s p e c t r a l p r o p e r t i e s o f t h i s m a t e r i a l were i d e n t i c a l w i t h t h o s e r e p o r t e d e a r l i e r . P r e p a r a t i o n o f 1 - ( l - H y d r o x y - 2 - c y c l o h e x e n y l ) - 3 - t e r t -b u t y l d i m e t h y l s i l o x y - 1 , 3 - c y c l o h e x a d i e n e 122 ( f i l m ) : 3400, 3070, 1659, 1607 cm -1 ; 1H nmr (CDC1-.) OSiMe^ Bu OH 122 - 142 -F o l l o w i n g the g e n e r a l p r o c e d u r e D o u t l i n e d above, 0.4 mmol o f the v i n y l l i t h i u m r e a g e n t 111 ( p r e p a r e d by r e a c t i o n o f the e n o l s i l y l e t h e r 108 w i t h n - b u t y l l i t h i u m ) was a l l o w e d t o r e a c t w i t h 2 - c y c l o h e x e n - l - o n e (50 mg, 0.52 mmol) i n t e t r a h y d r o f u r a n a t -78°C f o r l h . Normal workup, f o l l o w e d by removal o f t e t r a - n - b u t y l t i n and d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 123-130°C, 0.09 t o r r ) o f the r e s i d u e a f f o r d e d 103 mg (84%) o f the e n o l s i l y l e t h e r 122. T h i s m a t e r i a l e x h i b i t e d i r ( f i l m ) : 3400, 1648, 1601 c m - 1 ; 1 H nmr (CDC1 3) 6: 0.08 ( s , 6H, s i l y l m e t h y l s ) , 0.88 ( s , 9H, t e r t - b u t y l m e t h y l s ) , 1.50-1.86 (m, 5H, n o n - a l l y l i c methylene p r o t o n s and OH), 1.88-2.20 (m, 6H, a l l y l i c methylene p r o t o n s ) , 4.82 (m, IH, - C H = C ( 0 S i R 3 ) - ) , 5.57 (broad d, IH, c y c l o h e x e n y l C-2 v i n y l p r o t o n , J=10.5 H z ) , 5.72 (m, IH, =CH-C=), 5.91 (d o f t , IH, c y c l o h e x y l C-3 v i n y l p r o t o n , J=10.5 Hz, J'=7Hz). E x a c t mass c a l c d . f o r C 1 8 H 3 0 O 2 S i : 306.2014; found: 306.2008. P r e p a r a t i o n o f 1 - ( D i m e t h y l a m i n o ) m e t h y l - 3 - t e r t -b u t y l d i m e t h y l s i l o x y - 1 , 3 - c y c l o h e x a d i e n e 123 0SiMe2But -NMe, 123 F o l l o w i n g the g e n e r a l p r o c e d u r e D d e s c r i b e d above, 0.27 mmol o f the v i n y l l i t h i u m r e a g e n t 111 (prepared by r e a c t i o n o f the e n o l s i l y l e t h e r 110 w i t h m e t h y l l i t h i u m ) was a l l o w e d t o r e a c t w i t h s o l i d dimethyl(methylene)ammonium i o d i d e (65 mg, 0.35 mmol) i n t e t r a h y d r o f u r a n a t -78°C f o r l h , and a t room temperature f o r l h . Normal workup, f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 73-82°C, 0.1 t o r r ) o f the r e s i d u a l o i l gave 58 mg (81%) o f t h e e n o l s i l y l e t h e r 123. A g l c a n a l y s i s (column A) showed the p r e s ence o f one component. T h i s m a t e r i a l e x h i b i t e d i r ( f i l m ) : 3055, 2770, 1640, 1610 cm" 1; 1 H nmr (CDCl.^) 6: 0.08 ( s , 6H s i l y l m e t h y l s ) , 0.09 ( s , 9H, t e r t - b u t y l m e t h y l s ) , 2.04-2.24 (m, 4H, -CH2CH_2-) , 2.16 (s , 6H, amino m e t h y l s ) , 2.84 (broad s, 2H, -CH_ 2NMe 2), 4.82 (m, IH, -CH=C(OSiR 3)-), 5.58 (m, IH, -CH=CR-). E x a c t mass c a l c d . f o r C , r H o n N O S i : 267.2019; found: 267.2004. 15 29 P r e p a r a t i o n o f g - T r i a l k y l s t a n n y l Ketones and E s t e r s  G e n e r a l P r o c e d u r e E. To a c o l d (-20°C), s t i r r e d s o l u t i o n o f l i t h i u m p h e n y l t h i o -( t r i m e t h y l s t a n n y l ) c u p r a t e 7_2 (1.1-2.0 e q u i v a l e n t s ) i n anhydrous t e t r a h y d r o f u r a n (10 mL) under an atmosphere o f a r g o n , was added a s o l u t i o n (THF, ^lmL) o f the a p p r o p r i a t e s u b s t r a t e . The r e a c t i o n m i x t u r e was s t i r r e d a t -20°C f o r 15 min, and a t room tem p e r a t u r e f o r l h . M e t h a n o l (^0.2 mL) and e t h e r (^ 3 0 mL) were added, and the m i x t u r e was s t i r r e d a t room temperature f o r s e v e r a l m i n u t e s . The r e s u l t i n g y e l l o w s l u r r y was f i l t e r e d t h r o u g h a s h o r t column of f l o r i s i l - 144 -(lOg, 100-200 mesh). The column was e l u t e d w i t h a f u r t h e r 50 mL o f e t h e r and the e l u a n t was combined. Removal of the s o l v e n t , f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h ) o f t h e r e s i d u a l o i l a f f o r d e d the c o r r e s p o n d i n g p r o d u c t . G e n e r a l P r o c e d u r e F. To a c o l d (-78°C), s t i r r e d s o l u t i o n o f l i t h i u m p h e n y l t h i o -( t r i - n - b u t y l s t a n n y l ) c u p r a t e 7_3 (1.3-1.5 e q u i v a l e n t s ) i n anhydrous t e t r a h y d r o f u r a n (10 mL), under an atmosphere o f a r g o n , was added a s o l u t i o n (THF, ^1 mL) o f the a p p r o p r i a t e s u b s t r a t e . The r e a c t i o n m i x t u r e was s t i r r e d a t -78°C f o r l h , warmed t o -20°C, and s t i r r e d a t t h i s t e mperature f o r l h . The c o o l i n g b a t h was then removed and the r e a c t i o n m i x t u r e s t i r r e d f o r an a d d i t i o n a l p e r i o d o f l h . Methanol (^0.2 mL) and e t h e r (^30 mL) were added, and the m i x t u r e was s t i r r e d a t room t e m p e r a t u r e f o r s e v e r a l m i n u t e s . The r e s u l t i n g y e l l o w s l u r r y was f i l t e r e d t h r o ugh a s h o r t column o f f l o r i s i l ( l O g , 100-200 mesh). The column was e l u t e d w i t h a f u r t h e r 50 mL o f e t h e r and the e l u a n t was combined. Removal o f s o l v e n t a f f o r d e d a y e l l o w o i l , w h i c h was chromatographed on 20g o f s i l i c a g e l . E l u t i o n o f the column w i t h a m i x t u r e o f p e t r o l e u m e t h e r and e t h e r (9:1) gave, a f t e r c o n c e n t r a t i o n o f the a p p r o p r i a t e f r a c t i o n s , a m i x t u r e o f t e t r a - n - b u t y l t i n and h e x a - n - b u t y l d i t i n . F u r t h e r e l u t i o n o f t h e column gave, a f t e r c o n c e n t r a t i o n o f the a p p r o p r i a t e f r a c t i o n s and d i s t i l l a t i o n ( a i r - b a t h ) o f the r e s i d u e , the c o r r e s p o n d i n g p r o d u c t . - 145 -G e n e r a l P r o c e d u r e G." To a c o l d (-78°C), s t i r r e d s o l u t i o n o f t r i m e t h y l s t a n n y l -l i t h i u m (1.05-1.10 e q u i v a l e n t s ) i n anhydrous t e t r a h y d r o f u r a n (10 mL), under an atmosphere o f arg o n , was added a s o l u t i o n (THF, ^1 mL) o f the a p p r o p r i a t e s u b s t r a t e . A f t e r the r e a c t i o n m i x t u r e had been s t i r r e d a t -78°C f o r t h e approp-r i a t e l e n g t h o f t i m e , methanol (^0.5 mL) and e t h e r (^ 30 mL) were added. The r e s u l t i n g m i x t u r e was a l l o w e d t o warm t o room t e m p e r a t u r e and f i l t e r e d t h r o u g h a s h o r t column o f f l o r i s i l ( l O g , 100-200 mesh). The column was e l u t e d w i t h a f u r t h e r 50 mL o f e t h e r and the e l u a n t was combined. Removal o f the s o l v e n t , f o l l o w e d by d i s t i l l a t i o n o f t h e r e s i d u a l o i l a f f o r d e d the c o r r e s p o n d i n g p r o d u c t . 2, P r e p a r a t i o n o f 4 - M e t h y l - 4 - t r i m e t h y l s t a n n y l - 2 - p e n t a n o n e 13JL MegSn 131 F o l l o w i n g the g e n e r a l p r o c e d u r e E o u t l i n e d above, 0.75 mmol o f l i t h i u m p h e n y l t h i o ( t r i m e t h y l s t a n n y l ) c u p r a t e 72 was a l l o w e d t o r e a c t w i t h m e s i t y l o x i d e 130 (57 mg, 0.58 mmol) i n t e t r a h y d r o f u r a n (10 mL) a t -20°C f o r 15 min and a t room temp e r a t u r e f o r l h . Normal workup, f o l l o w e d by d i s t i l l a t i o n - 146 54 ( a i r - b a t h t e mperature 40-47°C, 0.3 t o r r ; r e c e i v e r c o o l e d t o -78°C) o f the crude p r o d u c t a f f o r d e d 116 mg (76%) o f the ketone 131. An a n a l y t i c a l sample was p r e p a r e d by p r e p a r a t i v e t i c on s i l i c a g e l ( d e v e l o p i n g s o l v e n t : p e t r o l -eum e t h e r - e t h e r , 98:2). T h i s m a t e r i a l e x h i b i t e d i r ( f i l m ) : 1713, 765 cm" 1; ^^ H nmr (CDC1 3) 6: -0.02 ( s , 9H, s t a n n y l m e t h y l s , J _ =61Hz), 2.10 ( s , 3H, -CO-CH,), 2.49 ( s , 2H, on—ri — j -CH„-CO-, J_, =66Hz) . E x a c t mass c a l c d . f o r C 0H, _OSn —z o n - t i o 1 / (M +-15): 249.0301; found: 249.0288. A n a l . c a l c d . f o r C 9H 2 QOSn: C 41.11, H 7.67; found: C 41.19, H 7.70. P r e p a r a t i o n o f 4 - M e t h y l - 4 - t r i - n - b u t y l s t a n n y l - 2 - p e n t a n o n e 132 n-BugSn 132 F o l l o w i n g the g e n e r a l p r o c e d u r e F o u t l i n e d above, 1.0 mmol of l i t h i u m p h e n y l t h i o ( t r i - n - b u t y l s t a n n y l ) c u p r a t e 7_2_ was a l l o w e d t o r e a c t w i t h m e s i t y l o x i d e 130 (66 mg, 0.67 mmol) a t -78°C f o r l h , a t -20°C f o r l h , and a t room tem p e r a t u r e f o r l h . Normal workup, f o l l o w e d by column chromatography o f the crude p r o d u c t and d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 120-128°C, 0.2 t o r r ) o f the o i l o b t a i n e d from the a p p r o p r i a t e f r a c t i o n s , a f f o r d e d 181 mg (69%) o f the ketone 132. An a n a l y t i c a l sample was o b t a i n e d by p r e p a r a t i v e t i c on s i l i c a - 147 -g e l ( d e v e l o p i n g s o l v e n t : p e t r o l e u m e t h e r - e t h e r , 98:2). T h i s m a t e r i a l e x h i b i t e d i r ( f i l m ) : 1718 cm" 1; 1 H nmr (CDC1 3) 6: 0.72 (m, 15H, -Sn(CH 2CH 2CH 2CH 3)), 1.12 ( s , 6H, t e r t i a r y m e t h y l s ) , 1.04-1.72 (m, 12H, -Sn(CH 2CH 2CH 2CH 3)), 2.11 ( s , 3H, -C0-CH_3) , 2.52 ( s , 2H, -CH2-CO-, J g n _ H = 6 0 H z ) A n a l . c a l c d . f o r C-^H^OSn: C 55.55, H 9.84; found: C 55.66, H 9.74. P r e p a r a t i o n o f 3 - T r i m e t h y l s t a n n y l c y c l o h e x a n o n e 69_ 2 4 r V >nMeo 69 a) R e a c t i o n o f L i t h i u m P h e n y l t h i o ( t r i m e t h y l s t a n n y l ) c u p r a t e  72 w i t h 2 - C y c l o h e x e n - l - o n e 6_8_ F o l l o w i n g t h e g e n e r a l p r o c e d u r e E o u t l i n e d above, 1.36 mmol o f l i t h i u m p h e n y l t h i o ( t r i m e t h y l s t a n n y l ) c u p r a t e 7_2_ was a l l o w e d t o r e a c t w i t h 2 - c y c l o h e x e n - l - o n e 68_ (66 mg, 0.68 mmol) i n t e t r a h y d r o f u r a n a t -20°C f o r 15 min, and a t room temp e r a t u r e f o r l h . Normal workup, f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h t e mperature 75-90°C, 0.2 t o r r ) o f the r e s i d u a l o i l a f f o r d e d 162 mg (91%) o f 3 - t r i m e t h y l s t a n n y l c y c l o h e x a n o n e 69. T i c and g l c a n a l y s e s ( s i l i c a g e l and column A, r e s p e c t i v e l y ) showed the p r e s e n c e o f one component. T h i s m a t e r i a l - 148 -e x h i b i t e d i r ( f i l m ) : 1712, 770 cm 1 ; 1 H nmr (CDC1 3) 6: -0.02 ( s , 9H, s t a n n y l m e t h y l s , J„ = 5 l H z ) , 140-2.15 on -ri (broad m, 5H, -CH_2CH2CH (SnR 3) -) , 2.15-2.54 (m, 4H, -CH 2-CO=CH 2-). E x a c t mass c a l c d . f o r CgH^OSn: 262.0380; found: 262.0394. b) R e a c t i o n o f Me 3SnCu•LiBr•SMe 2 94 w i t h 2 - C y c l o h e x e n - l - o n e 68 F o l l o w i n g the g e n e r a l p r o c e d u r e B o u t l i n e d e a r l i e r , 0.65 mmol o f the t r i m e t h y l s t a n n y l c o p p e r r e a g e n t 9_4 was a l l o w e d t o r e a c t w i t h 2 - c y c l o h e x e n - l - o n e 6_8 (48 mg, 0.50 mmol) i n t e t r a h y d r o f u r a n a t -48°C f o r 2h, a t -20°C f o r l h , and a t room tem p e r a t u r e f o r l h . Normal workup gave a y e l l o w o i l . A g l c a n a l y s i s (column A) showed t h a t t h i s m a t e r i a l was composed o f a m i x t u r e o f the ketones 69_ and 146 i n a r a t i o o f 55:45, r e s p e c t i v e l y . The components were s e p a r a t e d by d i s t i l l a t i o n ( a i r - b a t h ) . The pure 3 - t r i m e t h y l s t a n n y l c y c l o h e x a n o n e 6_9 (42 mg, 32%) e x h i b i t e d s p e c t r a l d a t a i d e n t i c a l w i t h t h o s e r e p o r t e d e a r l i e r . A g l c a n a l y s i s o f the d i s t i l l e d ( a i r - b a t h t e m p e r a t u r e 148-159°C, 0.09 t o r r ) 2 - ( 3 - k e t o c y c l o h e x y l ) - 3 - t r i m e t h y l -s t a n n y l c y c l o h e x a n o n e 146 (43 mg, 48%) showed the p r e s e n c e of one major component (>96%). T h i s m a t e r i a l e x h i b i t e d i r ( f i l m ) : 1705, 775 cm" 1; 1 H nmr (CDC1 3) 6: 0.04 ( s , 9H, s t a n n y l m e t h y l s , J 0 =50Hz), 1.30-2.14 (broad m, 10H), on -ri 2.14-2.66 (broad m, 7H). E x a c t mass c a l c d . f o r C, C H 0 .-0~Sn: 15 26 2 358.0955; fo u n d : 358.0964. - 149 -P r e p a r a t i o n o f 3 - T r i - n - b u t y l s t a n n y l c y c l o h e x a n o n e 135 0 A \ ^ S n B u n 3 135 F o l l o w i n g the g e n e r a l p r o c e d u r e F o u t l i n e d above, 1.0 mmol of l i t h i u m p h e n y l t h i o ( t r i - n - b u t y l s t a n n y l ) c u p r a t e 73 was a l l o w e d t o r e a c t w i t h 2 - c y c l o h e x e n - l - o n e 6_8 (64 mg, 0.67 mmol) i n t e t r a h y d r o f u r a n a t -78°C f o r l h , a t -20°C f o r l h , and a t room tem p e r a t u r e f o r l h . Normal workup, f o l l o w e d by column chromatography o f the crude p r o d u c t and d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 165-169°C, 0.2 t o r r ) o f the o i l o b t a i n e d from the a p p r o p r i a t e f r a c t i o n s , gave 202 mg (78%) o f the ketone 135. T i c and g l c a n a l y s e s ( s i l i c a g e l and column A, r e s p e c t i v e l y ) showed the p r e s e n c e of one component. T h i s m a t e r i a l e x h i b i t e d i r ( f i l m ) : 1710 cm 1 ; 1 H nmr (CDC1 3) 6 : 0.76-1.02 (m, 15H, -Sn (CH^CH 2CH 2CH_ 3) 3 ) , 1.08-2.08 (broad m, 17H, -Sn (CH 2CH_ 2CH 2CH 3) 3 and -CH^CH^CH (SnR 3) -) , 2.08-2.48 (m, 4H, -CH 2-CO-CH 2-). E x a c t mass c a l c d . f o r C, oH o,0Sn: 388.1786; found: 388.1791. - 150 -P r e p a r a t i o n o f 3 , 5 , 5 - T r i m e t h y l - 3 - t r i m e t h y l s t a n n y l c y c l o h e x a n o n e 136 2 4 0 SnMer 136 F o l l o w i n g the g e n e r a l p r o c e d u r e E o u t l i n e d above, 1.36 mmol o f l i t h i u m p h e n y l t h i o ( t r i m e t h y l s t a n n y l ) c u p r a t e 72 was a l l o w e d t o r e a c t w i t h i s o p h o r o n e 133 (94 mg, 0.68 mmol) i n t e t r a h y d r o f u r a n a t -20°C f o r 15 min, and a t room temperature f o r l h . Normal workup a f f o r d e d a y e l l o w o i l . A g l c a n a l y s i s (column A) of t h i s m a t e r i a l showed t h a t a s m a l l amount of the s t a r t i n g m a t e r i a l 133 (^7%) was p r e s e n t . D i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 80-93°C, 0.06 t o r r ) o f the crude p r o d u c t a f f o r d e d 52 mg (69%) o f the ketone 136. T i c and g l c a n a l y s e s ( s i l i c a g e l and column A, r e s p e c t i v e l y ) showed the p r e s e n c e of one component. T h i s m a t e r i a l e x h i b i t e d i r ( f i l m ) : 1712, 750 cm" 1; "'"H nmr (270 MHz) (CDC1 3) 6: 0.07 ( s , 9H, s t a n n y l m e t h y l s , Ja =49Hz), 1.00 and 1.07 on—ti ( s , s, 6H, C-5 m e t h y l s ) , 1.28 ( s , 3H, C-3 m e t h y l , J 0 -64Hz), on—ri 1.59 and 1.91 (d, d, IH each C-4 methylene p r o t o n s , J^15Hz), 2.11-2.18 ( u n r e s o l v e d m, 3H), 2.54 (d, IH, C-2 methylene p r o t o n , J=14Hz) E x a c t mass c a l c d . f o r C 1 2 H 2 4 O S n : 304.0849; found 304.0870. - 151 -P r e p a r a t i o n o f 3 , 5 , 5 - T r i m e t h y l - 3 - t r i - n - b u t y l s t a n n y l - c y c l o h e x a n o n e 137 SnBun3 137 F o l l o w i n g the g e n e r a l p r o c e d u r e F o u t l i n e d above, 1.0 mmol of l i t h i u m p h e n y l t h i o ( t r i - n - b u t y l s t a n n y l ) c u p r a t e 73_ was a l l o w e d t o r e a c t w i t h i s o p h o r o n e 133 (92 mg, 0.67 mmol) i n t e t r a h y d r o f u r a n a t -78°C f o r l h , a t -20°C f o r l h , and a t room temperature f o r l h . Normal workup, f o l l o w e d by chromatography o f t h e c r u d e p r o d u c t and d i s t i l l a t i o n ( a i r -b a t h temperature 169-177°C, 0.2 t o r r ) o f the m a t e r i a l o b t a i n e d from the a p p r o p r i a t e f r a c t i o n s a f f o r d e d 185 mg (64%) o f the ketone 137. T i c and g l c a n a l y s e s ( s i l i c a g e l and column A, r e s p e c t i v e l y ) showed the p r e s e n c e o f one component. T h i s m a t e r i a l e x h i b i t e d i r ( f i l m ) 1711 cm 1 ; XH nmr (270 MHz) (CDC1 3) 6: 0.81-0.97 (m, 15H, -Sn (CH 2CH 2CH 2CH_ 3) 3 ) , 1.01 and 1.06 ( s , s, 6H, C-5 m e t h y l s ) , 1.34 ( s , 3H, C-3 m e t h y l ) , 1.20-1.56 (m, 12H, -Sn(CH 2CH 2CH 2CH 3) ), 1.64 and 1.98 (d, d, IH each, C-4 methylene p r o t o n s , J=13Hz) , 2.10-2.38 (m, 3H) , 2.61 (d, IH, C-6 methylene p r o t o n , J-13Hz). E x a c t mass c a l c d . f o r C 0 1H / 1 0OSn: 430.2258; found: 430.2264. P r e p a r a t i o n o f M e t h y l 3 - 152 -- T r i m e t h y l s t a n n y l b u t a n o a t e 138 a) R e a c t i o n o f L i t h i u m P h e n y l t h i o ( t r i m e t h y l s t a n n y l ) c u p r a t e  72 w i t h M e t h y l ( E ) - 2 - b u t e n o a t e 134 F o l l o w i n g the g e n e r a l p r o c e d u r e E o u t l i n e d above, 0.7 5 mmol o f the c u p r a t e r e a g e n t 7_2 was a l l o w e d t o r e a c t w i t h m e t h y l (E)-2-butenoate 134 (68 mg, 0.68 mmol) i n t e t r a h y d r o -f u r a n a t -20°C f o r 15 min and a t room temperature f o r l h . The r e a c t i o n m i x t u r e was quenched w i t h methanol. Normal workup, f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h t emperature 41-50°C, 0.2 t o r r ; r e c e i v e r c o o l e d t o -78°C) of the crude o i l gave 122 mg (67%) o f t h e e s t e r 138. An a n a l y t i c a l sample was o b t a i n e d by p r e p a r a t i v e t i c on s i l i c a g e l ( d e v e l o p i n g s o l v e n t : p e t r o l e u m e t h e r - e t h e r , 98:2). T h i s m a t e r i a l e x h i b i t e d i r ( f i l m ) : 1738, 1202, 770 cm" 1; 1H nmr (CDC1,) <5 : 0.02 ( s , 9H, s t a n n y l m e t h y l s , J _ = 5 l H z ) , J bn -H 1.17 (d, 3H, CH.-C-, J=7Hz, J 0 =68Hz), 1.30-1.62 (m, IH, —o on—ti - C H ( S n R 3 ) - ) , 2.50 (d, 2H, -CH_ 2-C0 2-, J=7Hz) , 3.66 ( s , 3H, -OMe) . A n a l . c a l c d . f o r CgH-^C^Sn: C 36.27, H 6.85; found C 36.64, H 6.94. - 153 -b) R e a c t i o n o f T r i m e t h y l s t a n n y l l i t h i u m w i t h M e t h y l (E)-2-Butenoate 134 F o l l o w i n g the g e n e r a l p r o c e d u r e G o u t l i n e d above, 0.75 mmol o f t r i m e t h y l s t a n n y l l i t h i u m was a l l o w e d t o r e a c t w i t h m e t h y l (E ) - 2 - b u t e n o a t e 134 (68 mg, 0.68 mmol) i n t e t r a h y d r o -f u r a n a t -78°C f o r 5 min. The r e a c t i o n m i x t u r e was quenched w i t h methanol. Normal workup, f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h ) gave 108 mg (71%) o f methy l 3 - t r i m e t h y l s t a n n y l -b u t a n o a t e 138. T h i s m a t e r i a l e x h i b i t e d s p e c t r a l p r o p e r t i e s w h i c h were i d e n t i c a l w i t h t h o s e d e s c r i b e d e a r l i e r . P r e p a r a t i o n o f M e t h y l 3 - T r i - n - b u t y l s t a n n y l b u t a n o a t e 1 3 9 O M e 139 F o l l o w i n g t h e g e n e r a l p r o c e d u r e F o u t l i n e d above, 1.3 mmol o f l i t h i u m p h e n y l t h i o ( t r i - n - b u t y l s t a n n y l ) c u p r a t e 7_3_ was a l l o w e d t o r e a c t w i t h m e t h y l ( E ) - 2 - b u t e n o a t e 134 o (100 mg, 1.0 mmol) i n t e t r a h y d r o f u r a n a t -78 C f o r l h , a t -20°C f o r l h , and a t room t e m p e r a t u r e f o r l h . Normal workup, f o l l o w e d by column chromatography o f t h e c r u d e p r o d u c t and d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 110-115°C, 0.25 t o r r ) o f t h e o i l o b t a i n e d from t h e a p p r o p r i a t e f r a c t i o n s - 154 -a f f o r d e d 287 mg (74%) o f the e s t e r 139. An a n a l y t i c a l sample was o b t a i n e d by p r e p a r a t i v e t i c on s i l i c a g e l ( d e v e l o p i n g s o l v e n t : p e t r o l e u m e t h e r - e t h e r , 98:2). T h i s m a t e r i a l e x h i b i t e d i r ( f i l m ) : 1738, 1200 cm "*"H nmr (400 MHz) (CDC1 3) 6: 0.81-0.95 (m, 15H, -Sn (CH 2CH 2CH 2CH_ 3) 3 ) , 1.21 (d, 3H, CH..CH-, J=7Hz, J e =60Hz), 1.26-1.37 and — J on — r l 1.41-1.53 (m, m, 12H, - Sn(CH 2CH 2CH 2CH 3),), 1.57-1.68 (m, IH, CH 3CH-) , 2.45 and 2.55 (both d o f d, IH each, -CH_2-CO-, J =15Hz, J'=9Hz and 7Hz, r e s p e c t i v e l y ) , 3.69 ( s , 3H, gem -C0 2Me) . A n a l . c a l c d . f o r C ^ H ^ C ^ S n : C 52.20, H 9.28; f ound: C 52.46, H 9.21. P r e p a r a t i o n o f E t h y l 3 - M e t h y l - 3 - t r i m e t h y l s t a n n y l - 2 - b u t e n o a t e  143 MeoSn ^> OEt 143 F o l l o w i n g the g e n e r a l p r o c e d u r e G o u t l i n e d above, 0.75 mmol o f t r i m e t h y l s t a n n y l l i t h i u m was a l l o w e d t o r e a c t w i t h e t h y l 3-methyl-2-butenoate 140 (87 mg, 0.68 mmol) i n t e t r a h y d r o f u r a n a t -78°C f o r 15 min. The r e a c t i o n m i x t u r e was quenched w i t h m ethanol. Normal workup, f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 115-123°C, 25 t o r r ) gave 147 mg (74%) o f the e s t e r 143. A pure sample was - 155 -o b t a i n e d by p r e p a r a t i v e t i c on s i l i c a g e l ( d e v e l o p i n g s o l v e n t : p e t r o l e u m e t h e r - e t h e r , 98:2). A g l c a n a l y s i s (column A) o f t h i s m a t e r i a l showed the presence o f one component w h i c h e x h i b i t e d i r ( f i l m ) : 1733, 760 c m - 1 ; 1 H nmr (CDC1_) 6: 0.01 ( s , 9H, s t a n n y l m e t h y l s , J _ =50Hz), J Sn—H 1.12 ( s , 6H, - C ( C H 3 ) 2 - , J S n _ H = 6 1 H z ) , 1.24 ( t , 3H, -OCH 2CH 3, J=7Hz), 2.32 ( s , 2H, -CH 2C0 2~, J S n _ H = 6 7 H z ) , 4.11 (q, 2H, -OCH 2CH 3, J=7Hz) . E x a c t mass c a l c d . f o r C-^H^G^Sn: 282.9781; found: 282.9792. P r e p a r a t i o n o f the E s t e r 145 142 145 F o l l o w i n g the g e n e r a l p r o c e d u r e G o u t l i n e d above, 0.53 mmol o f t r i m e t h y l s t a n n y l l i t h i u m was a l l o w e d t o r e a c t w i t h the e s t e r 142* (134 mg, 0.50 mmol) i n t e t r a h y d r o f u r a n a t -78°C f o r 15 min. Normal workup, f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 130-150°C, 0.07 t o r r ) a f f o r d e d 162 m< I am g r a t e f u l t o Mr. M. B u r m e i s t e r f o r s u p p l y i n g a sample o f t h i s compound. - 156 -(75%) o f the e s t e r 145. T i c and g l c a n a l y s e s ( s i l i c a g e l and column A, r e s p e c t i v e l y ) showed the p r e s e n c e o f one component. T h i s m a t e r i a l e x h i b i t e d i r ( f i l m ) : 1730, 1097, 758 cm" 1; 1 H nmr (CDC1-) 6: 0.03 ( s , 9H, s t a n n y l m e t h y l s , J c =60Hz), 0.94 ( s , 6H, t e r t i a r y m e t h y l s , 1.21 ( t , 3H, -C0 2CH 2CH 3, J=7Hz) , 1.42-2.04 (broad m, 8H) , 2.49 ( s , 2H, -CH_2CC>2Et, J S n _ H = 7 4 H z ) , (q, 2H, -C0 2CH_ 2CH 3, J=7Hz). E x a c t mass c a l c d . f o r C 1 8 H 3 4 0 4 S n : 434.1479; found 434.1495. 55 P r e p a r a t i o n o f 4 - T r i m e t h y l s t a n n y l - 2 - b u t a n o n e 147 147 148 a) R e a c t i o n o f T r i m e t h y l s t a n n y l l i t h i u m w i t h M e t h y l V i n y l Ketone F o l l o w i n g the g e n e r a l p r o c e d u r e G o u t l i n e d above, 1.0 mmol of t r i m e t h y l s t a n n y l l i t h i u m was a l l o w e d t o r e a c t w i t h m e t h y l v i n y l ketone (70 mg, 1.0 mmol) i n t e t r a h y d r o f u r a n a t -78°C f o r l h . Normal workup a f f o r d e d a y e l l o w o i l , w h i c h was chromatographed on 2.7 g o f s i l i c a g e l . E l u t i o n o f the column w i t h l i g h t p e t r o l e u m e t h e r (^10 mL) gave h e x a m e t h y l d i t i n . F u r t h e r e l u t i o n o f t h e column w i t h e t h e r (^12 mL) gave a - 157 -c o l o r l e s s o i l . A g l c a n a l y s i s (column A) o f t h i s m a t e r i a l showed t h a t i t was composed o f a m i x t u r e o f the ketone 147 and the d i k e t o n e 148 i n a r a t i o o f 76:24, r e s p e c t i v e l y . D i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 98-110°C, 35 t o r r ; 55 o l i t . bp 55-57 C, 5 t o r r ) o f the o i l th u s o b t a i n e d gave 102 mg (43%) o f 4 - t r i m e t h y l s t a n n y l - 2 - b u t a n o n e 147. T h i s m a t e r i a l e x h i b i t e d i r ( f i l m ) : 1710, 767 cm 1 ; "''H nmr (CDC1-.) 6: -0.02 ( s , 9H, s t a n n y l m e t h y l s , J„ =52Hz) , j bn~ ri 0.83 ( t , 2H, -CH„SnR_., J=7.5Hz, J c =54Hz), 2.08 ( s , —z j on—H 3H, -COMe), 2.60 ( t , 2H, -CH o-C0-, J=7.5Hz, J _ =58Hz). — o n - r i An a n a l y t i c a l sample was o b t a i n e d by p r e p a r a t i v e t i c on s i l i c a g e l ( d e v e l o p i n g s o l v e n t : l i g h t p e t r o l e u m e t h e r - e t h e r , 97:3). A n a l c a l c d . f o r C_H,,OSn: C 35.7 9, H 6.87; Found: C 35.78, H 6.95. F u r t h e r d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 110-120°C, 0.35 t o r r ) o f t h e r e m a i n i n g s t i l l p o t r e s i d u e a f f o r d e d 47 mg (31%, based on MVK) o f 3 - ( t r i m e t h y l s t a n n y l m e t h y l ) - 2 , 6 -h e p t a n e d i o n e 148. T h i s m a t e r i a l e x h i b i t e d i r ( f i l m ) : 1708 , 770 cm" 1; 1 H nmr (270 MHz) (CDC1 3) 6: 0.06 ( s , 9H, s t a n n y l m e t h y l s , J g n _ H = 5 2 H z ) , 0.81 and 0.98 (both d o f d, IH each, - C H 2 S n R 3 ) , J g e m = 1 3 H z , J'=8Hz and 7Hz, r e s p e c t i v e l y ) , 1.54-1.96 (m, 2H, -CH 2CH 2-CO-), 2.09 and 2.11 ( s , s, 6H, a c e t y l m e t h y l s ) , 2.34-2.37 (m, 2H, -CH2CH_2-CO-) , 2.49-2.64 (m, IH, t e r t i a r y p r o t o n ) . A n a l . c a l c d . f o r C-j^H^ 0 2 S n : C 43.32, H 7.27; found: C 43.36, H 7.30. - 158 -b) R e a c t i o n o f L i t h i u m P h e n y l t h i o ( t r i m e t h y l s t a n n y l ) c u p r a t e  72 w i t h M e t h y l V i n y l Ketone. To a c o l d (-78°C), s t i r r e d s o l u t i o n o f the c u p r a t e r e a g e n t 7_2 (2.0 mmol) i n 10 mL o f anhydrous t e t r a h y d r o f u r a n , under an atmosphere o f ar g o n , was added a s o l u t i o n o f methyl v i n y l ketone (105 mg, 1.5 mmol) i n t e t r a h y d r o f u r a n (1 mL). The r e s u l t i n g r e d s o l u t i o n was s t i r r e d a t -78°C f o r 30 min, warmed t o -20°C, and s t i r r e d a t t h i s t e m p e r a t u r e f o r l h . The c o o l i n g b a t h was removed and the m i x t u r e was s t i r r e d f o r an a d d i t i o n a l p e r i o d o f 3 0 min. S a t u r a t e d aqueous ammonium c h l o r i d e (.^ 0.2 mL) and e t h e r (^ 3 0 mL) were added. Normal workup (as i n g e n e r a l p r o c e d u r e E) f o l l o w e d by chromatography o f t h e r e s i d u a l o i l on s i l i c a g e l (as o u t l i n e d above) gave a c o l o r l e s s o i l . A g l c a n a l y s i s (column A) o f t h i s m a t e r i a l showed t h a t i t was composed o f a m i x t u r e o f the ketone 147 and the d i k e t o n e 148 i n a r a t i o o f 64:36, r e s p e c t i v e l y . Other minor u n i d e n t i f i e d p r o d u c t s (mostly h i g h b o i l i n g ) were a l s o p r e s e n t . S e p a r a t i o n o f the major p r o d u c t s by d i s t i l l a t i o n ( a i r - b a t h ) gave 96 mg (27%) o f 147 and 85 mg (37%) o f the d i k e t o n e 148. The s p e c t r a l p r o p e r t i e s o f t h e s e m a t e r i a l s were i d e n t i c a l w i t h t h o s e r e p o r t e d e a r l i e r . - 159 -c) R e a c t i o n o f L i t h i u m P h e n y l t h i o ( t r i m e t h y l s t a n n y l ) c u p r a t e 72 w i t h M e t h y l V i n y l Ketone i n the pr e s e n c e o f a c e t i c a c i d To a c o l d (-78°C), s t i r r e d s o l u t i o n o f l i t h i u m p h e n y l t h i o -( t r i m e t h y l s t a n n y l ) c u p r a t e (2.0 mmol) i n 10 mL o f anhydrous t e t r a h y d r o f u r a n , under ah atmosphere o f a r g o n , was added, d r o p w i s e , a m i x t u r e o f m e t h y l v i n y l ketone (105 mg, 1.5 mmol) and g l a c i a l a c e t i c a c i d (120 mg, 2.0 mmol) i n t e t r a -h y d r o f u r a n (1 mL). The r e s u l t i n g r e d s o l u t i o n was s t i r r e d a t -78°C f o r 30 min, warmed t o -20°C, and s t i r r e d a t t h i s t e m p e r a t u r e f o r l h . The c o o l i n g b a t h was then removed, and the r e a c t i o n m i x t u r e was s t i r r e d f o r an a d d i t i o n a l p e r i o d o f 30 min. S a t u r a t e d aqueous ammonium c h l o r i d e (^0.2 mL) and e t h e r (^30 mL) were added. Normal workup (as i n g e n e r a l p r o c e d u r e E ) , f o l l o w e d by chromatography o f the cru d e p r o d u c t on s i l i c a g e l (as o u t l i n e d above) gave a c o l o r l e s s o i l . A g l c a n a l y s i s (column A) o f t h i s m a t e r i a l showed t h a t i t was composed o f a m i x t u r e o f the ketone 147 and the d i k e t o n e 148 i n a r a t i o o f 97:3, r e s p e c t i v e l y . D i s t i l l a t i o n ( a i r - b a t h t e mperature 90-100°C, 30 t o r r ) o f t h i s m a t e r i a l a f f o r d e d 271 mg (77%) o f 4-t r i m e t h y l s t a n n y l - 2 - b u t a n o n e 147. The s p e c t r a l p r o p e r t i e s o f t h i s m a t e r i a l were i d e n t i c a l w i t h t h o s e r e p o r t e d e a r l i e r . - 160 -P r e p a r a t i o n o f E t h y l 3 - T r i m e t h y l s t a n n y l p r o p a n o a t e 149 OEt OEt OEt :0 149 150 a) R e a c t i o n o f T r i m e t h y l s t a n n y l l i t h i u m E t h y l A c r y l a t e F o l l o w i n g the g e n e r a l p r o c e d u r e A, o u t l i n e d above, 1.5 mmol o f t r i m e t h y l s t a n n y l l i t h i u m was a l l o w e d t o r e a c t w i t h e t h y l a c r y l a t e (150 mg, 1.5 mmol) i n t e t r a h y d r o f u r a n a t -78°C f o r l h . Normal workup a f f o r d e d a y e l l o w o i l w h i c h was chromatographed on 2.7 g o f s i l i c a g e l . E l u t i o n o f the column w i t h l i g h t p e t r o l e u m e t h e r (^10 mL) gave h e x a m e t h y l d i t i n . F u r t h e r e l u t i o n o f the column w i t h e t h e r (^12 mL) gave a c o l o r l e s s o i l . A g l c a n a l y s i s (column A) of t h i s m a t e r i a l showed t h a t i t was composed o f a m i x t u r e o f the e s t e r 149 and the d i e s t e r 150 i n a r a t i o o f 61:39, r e s p e c t i v e l y . Other minor u n i d e n t i f i e d p r o d u c t s were a l s o p r e s e n t . D i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 100-118°C, 30 t o r r ) o f t h i s m a t e r i a l a f f o r d e d 80 mg (20%) o f e t h y l 3 - t r i m e t h y l -s t a n n y l p r o p a n o a t e 149 wh i c h e x h i b i t e d i r ( f i l m ) : 1732, 775 c m - 1 ; 1 H nmr (CDC1 3) 6: 0.01 ( s , 9H, s t a n n y l m e t h y l s , ,= 59Hz) , - 161 -4.12 (q, 2H, -OCH 2CH 3, J=7Hz). An a n a l y t i c a l sample was o b t a i n e d by p r e p a r a t i v e t i c on s i l i c a g e l ( d e v e l o p i n g s o l v e n t : l i g h t p e t r o l e u m - e t h e r , 97:3). A n a l . c a l c d . f o r C 8 H 1 8 ° 2 S n : C 3 6 * 2 7 ' H 6 « 8 5 ' ' found: C 36.56, H 6.81. F u r t h e r d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 100-118°C, 0.3 t o r r ) o f the r e m a i n i n g s t i l l p o t r e s i d u e a f f o r d e d 81 mg (29% based on e t h y l a c r y l a t e ) of e t h y l 4 - c a r b e t h o x y - 5 -t r i m e t h y l s t a n n y l p e n t a n o a t e 150. T h i s m a t e r i a l e x h i b i t e d i r ( f i l m ) : 1727, 772 cm" 1; 1 H nmr (CDC1 3) 6: 0.03 ( s , 9H, s t a n n y l m e t h y l s , J 0 =53Hz). 0.93-1.06 (m, 2H, -CH_SnR 0), 1.21 ( t , 6H, ethoxy m e t h y l s , J=7Hz), 1.63-2.03 (m, 2H, -CH 2CH 2C0 2-), 2.08-2.43 (m, 2H, -CH 2CH 2C0 2"), 2.43-2.73 (m, IH, t e r t i a r y p r o t o n ) , 4.09 (q, 2H, ethoxy m e t h y l e n e s , J=7Hz). An a n a l y t i c a l sample was o b t a i n e d by p r e p a r a t i v e t i c on s i l i c a g e l ( d e v e l o p i n g s o l v e n t : l i g h t p e t r o l e u m e t h e r - e t h e r , 8:2). A n a l , c a l c d . f o r C. ,H_,-C' Sn: C 42.77, l o ZD 4 H 7.18; fou n d : C 42.41, H 7.03. b) R e a c t i o n o f L i t h i u m P h e n y l t h i o ( t r i m e t h y l s t a n n y l ) c u p r a t e  72 w i t h E t h y l A c r y l a t e . To a c o l d (-78°C), s t i r r e d s o l u t i o n o f l i t h i u m p h e n y l t h i o ( t r i m e t h y l s t a n n y l ) c u p r a t e 7_2 (1.0 mmol) i n 10 mL of anhydrous t e t r a h y d r o f u r a n , under an atmosphere o f a r g o n , was added a s o l u t i o n o f e t h y l a c r y l a t e (100 mg, 1.0 mmol) i n t e t r a h y d r o f u r a n (1 mL). The r e s u l t i n g r e d m i x t u r e was s t i r r e d a t -78°C f o r 30 min, warmed t o -20°C, and s t i r r e d - 162 -a t t h i s t e m p e r a t u r e f o r l h . The c o o l i n g b a t h was th e n removed and the r e a c t i o n m i x t u r e was s t i r r e d f o r an a d d i t i o n a l p e r i o d o f 30 min. S a t u r a t e d aqueous ammonium c h l o r i d e (^0.2 mL) and e t h e r (30 mL) were added. Normal workup (as i n g e n e r a l p r o c e d u r e E ) , f o l l o w e d by chromatography o f t h e r e s i d u a l o i l on s i l i c a g e l (as o u t l i n e d above) gave a c o l o r l e s s o i l . A g l c a n a l y s i s showed t h a t i t was composed of a m i x t u r e o f h e x a m e t h y l d i t i n and the d i e s t e r 150 Other minor u n i d e n t i f i e d i m p u r i t i e s were a l s o p r e s e n t . D i s t i l l -a t i o n ( a i r - b a t h t e m p e r a t u r e 110-125°C, 0.3 t o r r ) o f t h e r e s i d u e a f f o r d e d 30 mg (18%) o f e t h y l 4 - c a r b e t h o x y - 5 -t r i m e t h y l s t a n n y l p e n t a n o a t e 150, wh i c h was 91% pure by g l c a n a l y s i s . The i d e n t i t y o f d i e s t e r 150 was c o n f i r m e d by the i r and ~*"H nmr s p e c t r a o f t h i s m a t e r i a l . c) R e a c t i o n o f L i t h i u m P h e n y l t h i o ( t r i m e t h y l s t a n n y l ) c u p r a t e  72 w i t h E t h y l A c r y l a t e i n the p r e s e n c e o f A c e t i c A c i d . To a c o l d (-78 C ) , s t i r r e d s o l u t i o n o f l i t h i u m p h e n y l -t h i o ( t r i m e t h y l s t a n n y l ) c u p r a t e 7_2 (2.0 mmol) i n 10 mL o f anhydrous t e t r a h y d r o f u r a n , under an atmosphere o f a r g o n , was added, d r o p w i s e , a m i x t u r e o f e t h y l a c r y l a t e (50 mg, 0.5 mmol) and g l a c i a l a c e t i c a c i d (60 mg, 1.0 mmol) i n t e t r a h y d r o f u r a n (1 mL). The r e d s o l u t i o n was s t i r r e d a t -78°C f o r 30 min, warmed t o -20°C, and s t i r r e d a t t h i s t e m p e r a t u r e f o r l h . The c o o l i n g b a t h was then removed, and the r e a c t i o n m i x t u r e was s t i r r e d f o r an a d d i t i o n a l p e r i o d - 163 -o f 30 min. S a t u r a t e d aqueous ammonium c h l o r i d e (^0.2 mL) and e t h e r (^30 mL) were added. Normal workup (see g e n e r a l p r o c e d u r e E ) , f o l l o w e d by chromatography o f the r e s i d u a l o i l on s i l i c a g e l (as o u t l i n e d above) a f f o r d e d a c o l o r l e s s o i l . A g l c a n a l y s i s o f t h i s m a t e r i a l showed t h a t i t was composed o f a m i x t u r e o f the e s t e r 149 and t h e d i e s t e r 150 i n a r a t i o o f 93:7, r e s p e c t i v e l y . D i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 105-110°C, 38 t o r r ) o f the r e s i d u e a f f o r d e d 92 mg (70%) o f e t h y l 3 - t r i m e t h y l s t a n n y l p r o p a n o a t e 149. The s p e c t r a l p r o p e r t i e s o f t h i s m a t e r i a l were i d e n t i c a l w i t h t h o s e r e p o r t e d e a r l i e r . G e n e r a l P r o c e d u r e H: P r e p a r a t i o n o f o t , g - A c e t y l e n i c E s t e r s To a c o l d (-78°C), s t i r r e d s o l u t i o n o f the a p p r o p r i a t e t e r m i n a l a l k y n e i n anhydrous t e t r a h y d r o f u r a n under an atmosphere o f a r g o n , was added,dropwise, a s o l u t i o n o f m e t h y l - o r n - b u t y l l i t h i u m . A f t e r the a d d i t i o n was c o m p l e t e , the r e a c t i o n m i x t u r e was warmed t o -20°C, and s t i r r e d a t t h i s t e m p e r a t u r e f o r l h . A s o l u t i o n o f f r e s h l y d i s t i l l e d e t h y l c h l o r o f o r m a t e i n anhydrous t e t r a h y d r o f u r a n was added. A f t e r 15 min the m i x t u r e was warmed t o room tem p e r a t u r e and s t i r r e d f o r an a d d i t i o n a l p e r i o d o f l h . S a t u r a t e d aqueous ammonium c h l o r i d e and e t h e r were added. The o r g a n i c l a y e r was s e p a r a t e d , washed w i t h b r i n e , and d r i e d o v e r anhydrous magnesium s u l f a t e . Removal o f the s o l v e n t ( d i s t i l l a t i o n a t a t m o s p h e r i c p r e s s u r e ) , f o l l o w e d by f r a c t i o n a l d i s t i l l a t i o n - 164 -o f the r e s i d u a l o i l , u t i l i z i n g a 15 cm V i g r e u x column, a f f o r d e d the c o r r e s p o n d i n g a , 3 - a c e t y l e n i c e s t e r . 81 P r e p a r a t i o n o f E t h y l 2-Pentynoate 155 EtC=CC0 2Et 155 To a c o l d (-78°C), s t i r r e d s o l u t i o n o f 1-butyne (^1.69 g, 31 mmol), i n 50 mL o f anhydrous t e t r a h y d r o f u r a n , under a r g o n , was added a s o l u t i o n o f m e t h y l l i t h i u m i n e t h e r (20 mL, 28 mmol). The r e s u l t i n g m i x t u r e was warmed t o -20°C and s t i r r e d a t t h i s t e m p e r a t u r e f o r l h . F o l l o w i n g the g e n e r a l p r o c e d u r e H o u t l i n e d above, the c o l d (-20°C) m i x t u r e was t r e a t e d w i t h a s o l u t i o n o f e t h y l c h l o r o f o r m a t e (3.95 g, 36 mmol) i n 10 mL o f anhydrous t e t r a h y d r o f u r a n . A f t e r the r e a c t i o n m i x t u r e had been s t i r r e d f o r l h a t room t e m p e r a t u r e , i t was t r e a t e d w i t h s a t u r a t e d aqueous ammonium c h l o r i d e . Normal workup, f o l l o w e d by f r a c t i o n a l d i s t i l l a t i o n o f the crude p r o d u c t , u t i l i z i n g a 15 cm V i g r e u x column, a f f o r d e d 2.93 g (83%) o f pure e t h y l 2-pentynoate 155 (bp 172-174°C; l i t . 8 1 bp 67-68°C, 18 t o r r ) . T h i s m a t e r i a l e x h i b i t e d i r ( f i l m ) : 2255, 1708 cm" 1; 1 H nmr (CDC1 3) <5 : 1.21 ( t , 3H, CCH2CH_3, J=7.5Hz), 1.31 ( t , 3H, -OCH 2CH 3, J=7.0Hz), 2.37 (q, 2H, CCH 2CH 3, J=7Hz) , 4.24 (q, 2H, -OCH_2CH3, J=7.0Hz). - 165 -P r e p a r a t i o n o f E t h y l 2-Butynoate 160 ° Z MeC=CC02Et 160 To a c o l d (-78°C), s t i r r e d s o l u t i o n o f propyne (^1.10 g, 27.5 itimol) i n 4 0 mL o f anhydrous t e t r a h y d r o f u r a n , under an atmosphere o f ar g o n , was added a s o l u t i o n o f m e t h y l l i t h i u m i n e t h e r (17.8 mL, 25 mmol). The r e s u l t i n g m i x t u r e was warmed t o -20°C and s t i r r e d a t t h i s t e m p e r a t u r e f o r l h . F o l l o w i n g the g e n e r a l p r o c e d u r e H o u t l i n e d above, the c o l d (-20°C) m i x t u r e was t r e a t e d w i t h a s o l u t i o n o f e t h y l c h l o r o f o r m a t e (3.52 g, 32.5 mmol) i n 10 mL o f anhydrous t e t r a h y d r o f u r a n . Normal workup, f o l l o w e d by f r a c t i o n a l d i s t i l l a t i o n a f f o r d e d 2.16 g (77%) o f pure e t h y l 2-butynoate 160 (bp 162-164°C, l i t . 8 2 bp 163-164°C). T h i s m a t e r i a l e x h i b i t e d i r ( f i l m ) : 2230, 1707, 1260 cm" 1; 1 H nmr (CDClg) 6: 1.31 ( t , 3H, -OCH 2CH 3, J=7Hz), 2.01 ( s , 3H, a l k y n y l m e t h y l ) , 4.25 (q, 2H, -OCH_2CH3 , J=7Hz) . 8 3 P r e p a r a t i o n o f E t h y l 4,4-Dimethyl-2-pentynoate 162 t-BuC=CC02Et 162 To a c o l d (-78°C), s t i r r e d s o l u t i o n o f 3 , 3 - d i m e t h y l - l -butyne (0.82 g, 10 mmol) i n 30 mL o f anhydrous t e t r a h y d r o f u r a n , - 166 -under a r g o n , was added d r o p w i s e , a s o l u t i o n o f n - b u t y l l i t h i u m i n hexane (6.56 mL, 10.5 mmol). The r e s u l t i n g m i x t u r e was warmed t o -20°C, and s t i r r e d a t t h i s t e m p e r a t u r e f o r l h . F o l l o w i n g t h e g e n e r a l p r o c e d u r e H o u t l i n e d above, t h e c o l d (-20°C) m i x t u r e was t r e a t e d w i t h a s o l u t i o n o f e t h y l c h l o r o f o r m a t e (1.41 g, 13 mmol) i n 10 mL o f anhydrous t e t r a h y d r o f u r a n and s t i r r e d a t room tem p e r a t u r e f o r l h . Normal workup, f o l l o w e d by f r a c t i o n a l d i s t i l l a t i o n o f t h e crude p r o d u c t a f f o r d e d 1.33 g (86%) o f pure e t h y l 4 , 4 - d i m e t h y l - 2 - p e n t y n o a t e 162 (bp 81-84°C, 25 t o r r ; l i t . 8 3 bp 7 5°C, 15 t o r r ) . T h i s m a t e r i a l e x h i b i t e d i r ( f i l m ) : 2215, 1708, 1280 cm" 1; """H nmr (CDC1 3) 6: 1.29 (s , 9H, t e r t i a r y m e t h y l s ) , 1.32 ( t , 3H, -OCH 2CH 3, J=7Hz), 4.26 (q, 2H, -OCH_2CH3, J=7Hz). P r e p a r a t i o n o f M e t h y l 5 - ( t e r t - b u t y l d i m e t h y l s i l o x y ) - 2 -p e n t y n o a t e 161 ^-C=CC0 2Me t-BuMe2SiO—' 161 To a s t i r r e d s o l u t i o n o f m e t h y l 5-hydroxy-2-pentynoate* * I am v e r y g r a t e f u l t o P r o f e s s o r L. W e i l e r and Dr. P.E. Sum f o r a sample o f t h e t e t r a h y d r o p y r a n y l e t h e r o f t h i s compound, whi c h was r e a d i l y h y d r o l y z e d (aq. HCI, MeOH, room t e m p e r a t u r e , l h ) t o the f r e e a l c o h o l . - 167 -(2.80 g, 22 mmol) in 25 mL of N,N-dimethylformamide, under an atmosphere of argon was added, successively, imidazole (3.71 g, 55 mmol) and t e r t - b u t y l d i m e t h y l s i l y l chloride (3.96 g, 26 mmol). After the reaction mixture had been s t i r r e d at room temperature for 20h, i t was di l u t e d with 5% (w/v) aqueous sodium bicarbonate and thoroughly extracted with ether. The combined extract was washed with 5%(w/v) aqueous sodium bicarbonate and dried over anhydrous magnesium su l f a t e . Removal of the solvent, followed by d i s t i l l a t i o n (air-bath temperature 72-79°C, 0.08 torr) of the residual o i l afforded 4.91 g (92%) of the a,3-acetylenic ester 161. A glc analysis (column A) of this material indicated that i t was a,97% pure. This material exhibited i r (f i l m ) : 2240, 1717, 1258 cm"1; 1H nmr (CDC13) 6: 0.08 (s, 6H, s i l y l methyls), 0.90 (s, 9H, te r t - b u t y l methyls), 2.56 (t, 2H, -CH_2-CH20-, J=7Hz) , 3.77 (s, 3H, -CC^Me) , 3.81 (t, 2H, -CH.CH 0-, J=7Hz) . Exact mass calcd. for C 0H n -,0_Si (M +-15): 185.0634; found: 185.0632. Preparation of B-Trimethylstannyl-a , B-unsaturated Esters General Procedure I. To a cold (-100°C), vigorously s t i r r e d solution of lithium phenylthio (trimethylstannyl) cuprate 7_2 (1.00 mmol) in 10 mL of anhydrous tetrahydrofuran, under an atmosphere of argon, was added, dropwise, a solution (THF, ^ 0.5 mL) - 168 -o f the a p p r o p r i a t e a,3-acetylenic e s t e r (0.50 mmol) c o n t a i n i n g e i t h e r d r y methanol o r d r y e t h a n o l (0.85 mmol). The r e a c t i o n m i x t u r e was s t i r r e d a t -100°C f o r 15 min, warmed t o -78°C, and then s t i r r e d f o r an a d d i t i o n a l 3h. A f t e r s u c c e s s i v e a d d i t i o n o f methanol o r e t h a n o l (^0.2 mL) and e t h e r (^30 mL), the m i x t u r e was a l l o w e d t o warm t o room t e m p e r a t u r e . The r e s u l t i n g y e l l o w s l u r r y was f i l t e r e d t h r o u g h a s h o r t column o f s i l i c a g e l (10 g ) . The column was e l u t e d w i t h a f u r t h e r 30 mL o f e t h e r and the combined e l u a n t was e v a p o r a t e d under reduced p r e s s u r e . The r e s i d u e was chromatographed on 2.7 g o f s i l i c a g e l . E l u t i o n o f the column w i t h l i g h t p e t r o l e u m e t h e r (^10 mL) gave h e x a m e t h y l d i t i n . F u r t h e r e l u t i o n o f the column w i t h e t h e r (^ 8 mL), f o l l o w e d by c o n c e n t r a t i o n and d i s t i l l a t i o n ( a i r - b a t h ) o f the cru d e p r o d u c t , gave the c o r r e s p o n d i n g 3 - t r i m e t h y l s t a n n y l - a , 3 - u n s a t u r a t e d e s t e r . G e n e r a l P r o c e d u r e J . The g e n e r a l p r o c e d u r e J was e s s e n t i a l l y t h e same as p r o c e d u r e I e x c e p t t h a t 1.50 mmol of l i t h i u m p h e n y l t h i o -( t r i m e t h y l s t a n n y l ) c u p r a t e 7_2 was used and the r e a c t i o n was c a r r i e d o u t a t -100°C f o r 15 min and a t -78°C f o r 6h. G e n e r a l P r o c e d u r e K. To a c o l d (-78°C), s t i r r e d s o l u t i o n o f l i t h i u m p h e n y l t h i o ( t r i m e t h y l s t a n n y l ) c u p r a t e 7_2 (0.60 mmol) i n - 169 -10 mL o f anhydrous t e t r a h y d r o f u r a n , under an atmosphere o f a r g o n , was added,dropwise, a s o l u t i o n (THF, ^ 0.5 mL) o f the a p p r o p r i a t e a , 3 - a c e t y l e n i c e s t e r (0.50 mmol). A f t e r 15 min the r e a c t i o n m i x t u r e was warmed t o -48°C and s t i r r e d a t t h i s t e m p e r a t u r e f o r 4h. Methanol o r e t h a n o l (^0.2 mL) and e t h e r (^30 mL) were added and the m i x t u r e was a l l o w e d t o warm t o room t e m p e r a t u r e . Normal w rkup (as i n g e n e r a l p r o c e d u r e I ) , f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h ) o f the cru d e p r o d u c t gave t h e c o r r e s p o n d i n g 3 - t r i m e t h y l s t a n n y l - a , 3 - u n s a t u r a t e d e s t e r . G e n e r a l P r o c e d u r e L. The g e n e r a l p r o c e d u r e was e s s e n t i a l l y t h e same as pr o c e d u r e K e x c e p t t h a t 0.7 mmol o f the c u p r a t e r e a g e n t 72 was used. P r e p a r a t i o n o f E t h y l (E)-and ( Z ) - 3 - T r i m e t h y l s t a n n y l -2-pentenoate (156 and 157) To a c o l d (-78 C ) , s t i r r e d s o l u t i o n o f l i t h i u m p h e n y l t h i o ( t r i m e t h y l s t a n n y l ) c u p r a t e 7_2 (0.65 mmol) i n 10 mL o f anhydrous t e t r a h y d r o f u r a n , under a r g o n , was added 156 157 - 170 -a s o l u t i o n (THF, ^ 0.5 mL) o f e t h y l 2-pentynoate 155 (63 mg, 0.50 mmol). The r e a c t i o n m i x t u r e was s t i r r e d a t -78°C f o r 3h. Methanol (^0.2 mL) and e t h e r (^30 mL) were added, and the r e s u l t i n g m i x t u r e was a l l o w e d t o warm t o room t e m p e r a t u r e . Normal workup (as i n g e n e r a l p r o c e d u r e I) f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e (115-128°C, 20 t o r r ) o f the crud e p r o d u c t a f f o r d e d 99 mg (69%) o f a c o l o r l e s s o i l . A g l c a n a l y s i s (column A) o f t h i s m a t e r i a l showed t h a t i t was composed o f a m i x t u r e of the ( E ) - and ( Z ) - 3 - t r i m e t h y l s t a n n y l - a , g - u n s a t u r a t e d e s t e r s 156 and 157, i n a r a t i o o f 68:32. An a n a l y t i c a l sample o f each was o b t a i n e d by p r e p a r a t i v e t i c on s i l i c a g e l ( d e v e l o p i n g s o l v e n t : p e t r o l e u m e t h e r - e t h e r , 99:1). The pure (E)-isomer 156 ( r f 0.25) e x h i b i t e d uv (MeOH) A M : 220 nm (e= 13,800), i r ( f i l m ) : 1715, 1598, 1175, 775 cm" 1; 1 H nmr (CDC1 3) 6: 0.12 ( s , 9H, s t a n n y l m e t h y l s , J S n _ H = 5 4 H z ) , 0.99 ( t , 3H, CH_3CH2C=, J=8Hz), 1.22 ( t , 3H, -OCH 2CH 3, J=7Hz), 2.85 (broad q, 2H, CH 3CH 2C=, J=8Hz), 4.11 ( q ^ 2H, -OCH 2CH 3, J=7Hz). E x a c t mass c a l c d . f o r C 9 H 1 7 ° 2 S n ( M + ~ 1 5 ) : 277.0250; f o u n d : 277.0250. A n a l . c a l c d . f o r C 1 Q H 2 0 O 2 S n : C 41.28, H 6.93; found: C 41.36, H 7.02. The pure ( Z ) - i s o m e r 157 ( r f 0.41) e x h i b i t e d uv (MeOH) A : 218 (e= 9,300); i r ( f i l m ) : 1701, 1601, 1195, 773 cm" 1; l l l dX 1 H nmr (CDC1 3) 6: 0.12 ( s , 9H, s t a n n y l m e t h y l s , J S n _ H = 5 4 H z ) , 0.98 ( t , 3H, CH 3CH 2C=, J=7.5Hz), 1.24 ( t , 3H, -OCH 2CH 3, - 171 -J=7Hz), 2.41 (broad q, 2H, CH3CH_2C=, J=7.5Hz), 4.15 (q, 2H, -OCH_2CH3, J=7Hz) , 6.34 ( t , IH, v i n y l p r o t o n , J^2Hz, J„ =121Hz). E x a c t mass c a l c d . f o r C QH,-,0 oSn (M +-15) : 277.0252; fo u n d : 277.0252. A n a l . c a l c d . f o r C 1 0 H 2 0 O 2 S n : C 41.28, H 6.93; f o u n d : C 41.58,.H 7.10. P r e p a r a t i o n o f E t h y l ( E ) - 3 - T r i m e t h y I s t a n n y 1 - 2 - p e n t e n o a t e 156 MeoSn \ Et C0 2Et 156 a) By r e a c t i o n o f L i t h i u m P h e n y l t h i o ( t r i m e t h y l s t a n n y l ) c u p r a t e  72 w i t h E t h y l 2-Pentynoate 155 a t -100°C. To a c o l d (-100°C), s t i r r e d s o l u t i o n o f l i t h i u m p h e n y l t h i o ( t r i m e t h y l s t a n n y l ) c u p r a t e 7_2 (1.25 mmol) i n 10 mL o f anhydrous t e t r a h y d r o f u r a n , under a r g o n , was added a s o l u t i o n (THF, ^0.5 mL) o f e t h y l 2-pentynoate (63 mg, 0.50 mmol). The r e a c t i o n m i x t u r e was s t i r r e d a t -100°C f o r 6h. Methanol (^0.2 mL) and e t h e r (^30 mL) were added, and the r e s u l t i n g m i x t u r e was a l l o w e d t o warm t o room t e m p e r a t u r e . Normal workup (as i n g e n e r a l p r o c e d u r e I ) , f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 110-124°C, 20 t o r r ) o f the crude p r o d u c t a f f o r d e d 117 mg (81%) o f a c o l o r l e s s o i l . A g l c a n a l y s i s (column A) o f t h i s m a t e r i a l showed t h a t i t was composed o f a m i x t u r e o f e t h y l ( E ) - and - 172 -(Z)-3-trimethylstannyl-2-pentenoate (156 and 157) i n a r a t i o o f 97:3, r e s p e c t i v e l y . The i d e n t i t y o f the ( E ) -isomer 156 was c o n f i r m e d by t h e i r and nmr s p e c t r a of t h i s m a t e r i a l . b) By R e a c t i o n o f l i t h i u m p h e n y l t h i o ( t r i m e t h y l s t a n n y l ) c u p r a t e  72 w i t h E t h y l 2-Pentynoate i n the Pr e s e n c e o f M e t h a n o l . F o l l o w i n g the g e n e r a l p r o c e d u r e I o u t l i n e d above, a m i x t u r e o f e t h y l 2-pentynoate 155 (63 mg, 0.50 mmol) and methanol ( 3 4 y l , 0.85 mmol) was a l l o w e d t o r e a c t w i t h l i t h i u m p h e n y l t h i o ( t r i m e t h y l s t a n n y l ) c u p r a t e 7_2_ (1.00 mmol) i n t e t r a h y d r o f u r a n a t -100°C f o r 15 min, and a t -78°C f o r an a d d i t i o n a l 3h. Normal workup, f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 110-125°C, 20 t o r r ) o f t h e c r u d e o i l a f f o r d e d 115 mg (79%) o f e t h y l ( E ) - 3 - t r i m e t h y l s t a n n y l - 2 -p e n t y n o a t e 156. A g l c a n a l y s i s (column A) o f t h i s m a t e r i a l showed t h a t i t c o n t a i n e d <1% o f the (Z)-isomer 157. The i d e n t i t y o f the e s t e r 156 was c o n f i r m e d by the s p e c t r a l d a t a ( i r , nmr) o f the d i s t i l l e d m a t e r i a l . P r e p a r a t i o n o f E t h y l ( Z ) - 3 - T r i m e t h y l s t a n n y l - 2 - p e n t e n o a t e 157 Et 157 F o l l o w i n g the g e n e r a l p r o c e d u r e K o u t l i n e d above, e t h y l 2-pentynoate 155 (63 mg, 0.50 mmol) was a l l o w e d t o r e a c t w i t h l i t h i u m p h e n y l t h i o ( t r i m e t h y l s t a n n y l ) c u p r a t e 72_ (0.60 mmol) i n t e t r a h y d r o f u r a n a t -78°C f o r 15 min and a t -48°C f o r 4h. The r e a c t i o n m i x t u r e was quenched w i t h m e t h a n o l . Normal workup, f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h maximum temperature 125°C, 20 t o r r ) a f f o r d e d 110 mg (76%) o f a c o l o r l e s s l i q u i d . A g l c a n a l y s i s (column A) o f t h i s m a t e r i a l showed t h a t i t was composed o f e t h y l ( E ) - and ( Z _ ) - 3 - t r i m e t h y l s t a n n y l - 2 - p e n t e n o a t e (156 and 157) i n a r a t i o o f 2:98, r e s p e c t i v e l y . The i d e n t i t y o f the e s t e r 157 was c o n f i r m e d by the s p e c t r a l d a t a ( i r , "'"H nmr) o f the d i s t i l l e d m a t e r i a l . P r e p a r a t i o n o f E t h y l ( E ) - 3 - T r i m e t h y l s t a n n y l - 2 - b u t e n o a t e 163 MeoSn K Me C02Et 163 a) S m a l l S c a l e F o l l o w i n g g e n e r a l p r o c e d u r e I o u t l i n e d above, a m i x t u r e o f e t h y l 2-butynoate 160 (56 mg, 0.50 mmol) and methanol ( 3 5 u l , 0.85 mmol) was a l l o w e d t o r e a c t w i t h l i t h i u m p h e n y l t h i o ( t r i m e t h y l s t a n n y l ) c u p r a t e 7_2 (1.00 mmol) i n t e t r a h y d r o f u r a n a t -100°C f o r 15 min, and a t -78°C f o r an a d d i t i o n a l 3h. Normal workup f o l l o w e d by d i s t i l l a t i o n ( a i r -b a t h t e m p e r a t u r e 105-113°C, 20 t o r r ) o f the cru d e o i l a f f o r d e d - 174 -108 mg (79%) o f e s s e n t u a l l y pure (E)-isomer 163. A g l c a n a l y s i s (column A) o f t h i s m a t e r i a l showed t h a t i t c o n t a i n e d <1% o f the ( Z ) - i s o m e r 166. T h i s m a t e r i a l e x h i b i t e d uv (MeOH) X 0 1 0 _ , _ . . o r m N • max 218.5 nm ( e = 14,800); i r ( f i l m ) ; 1712, 1603, 1180, 773 cm" 1; 1 H nmr (CDC1 3) 6: 0.10 ( s , 9H, s t a n n y l m e t h y l s , J g n _ H = 5 4 H z ) , 1.22 ( t , 3H, -OCH 2CH 3, J=7Hz), 2.34 (d, 3H, v i n y l m e t h y l , J=2Hz, J _ =50Hz), fan-rl 4.12 (q, 2H, -OCH 2CH 3, J=7Hz), 5.95 (q, IH, v i n y l p r o t o n , J-2Hz, J 0 =73Hz) . E x a c t mass c a l c d . f o r C0H-. ,.0-Sn on—rl o l b Z (M +-15): 263.0094; fo u n d : 263.0074. An a n a l y t i c a l sample was o b t a i n e d by p r e p a r a t i v e t i c on s i l i c a g e l ( d e v e l o p i n g s o l v e n t : p e t r o l e u m e t h e r - e t h e r , 99:1; r f 0.21). A n a l . c a l c d . f o r C g H 1 8 0 2 S n : C 39.03, H 6.55; found: C 39.06, H 6.50. b) Large S c a l e To a c o l d (-100°C), v i g o r o u s l y s t i r r e d m i x t u r e o f l i t h i u m p h e n y l t h i o ( t r i m e t h y l s t a n n y l ) c u p r a t e 7_2_ (15.0 mmol) and methanol (12.8 mmol) i n 100 mL o f anhydrous t e t r a h y d r o -f u r a n , under a r g o n , was added, d r o p w i s e o v e r a p e r i o d o f 2 min, a s o l u t i o n (THF,^4mL) o f e t h y l 2-butenoate 160 (0.84 The r e a c t i o n m i x t u r e was s t i r r e d a t -100°C f o r 15 min, warmed t o -78°C, and s t i r r e d a t t h i s t e mperature f o r 4h. Methanol (^ 2 mL) and e t h e r (^3 00 mL) were added and the r e s u l t a n t m i x t u r e was a l l o w e d t o warm t o room t e p e r a t u r e . The r e s u l t i n g y e l l o w s l u r r y was f i l t e r e d t h r o u g h a s h o r t - 175 -column o f f l o r i s i l (50g, 100-200 mesh). The column was e l u t e d w i t h a f u r t h e r 200 mL o f e t h e r and the combined e l u a n t was c o n c e n t r a t e d . The r e s i d u a l o i l was chromato-graphed on 100 g o f s i l i c a g e l . E l u t i o n o f the column w i t h a 98:2 m i x t u r e o f l i g h t p e t r o l e u m e t h e r and e t h e r gave 64 mg (3%) o f e t h y l ( Z ) - t r i m e t h y l s t a n n y l - 2 - b u t e n o a t e 166. F u r t h e r e l u t i o n o f the column gave, a f t e r c o n c e n t r a t i o n o f the a p p r o p r i a t e f r a c t i o n s and d i s t i l l a t i o n ( a i r - b a t h t e m perature 103-115°C, 25 t o r r ) o f the r e s u l t a n t o i l , 1.52 g (74%) o f pure e t h y l ( E ) - t r i m e t h y l s t a n n y l - 2 - b u t e n o a t e 163. The s p e c t r a l p r o p e r t i e s ( i r , "*"H nmr) of t h i s m a t e r i a l were i d e n t i c a l w i t h t h o s e r e p o r t e d e a r l i e r . P r e p a r a t i o n o f E t h y l ( Z ) - 3 - T r i m e t h y l s t a n n y I - 2 - b u t e n o a t e 166 MeoSn C0 9Et 3 ^ 2 Me 166 a) S m a l l S c a l e F o l l o w i n g the g e n e r a l p r o c e d u r e K o u t l i n e d above, e t h y l 2-butynoate 160 (56 mg, 0.50 mmol) was a l l o w e d t o r e a c t w i t h l i t h i u m p h e n y l t h i o ( t r i m e t h y l s t a n y l ) c u p r a t e 7_2 (0.60 mmol) i n t e t r a h y d r o f u r a n a t -78°C f o r 15 min, and a t -48°C f o r an a d d i t i o n a l 4h. The r e a c t i o n m i x t u r e was quenched w i t h methanol. Normal workup, f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 103-115°C, 20 t o r r ) o f the cru d e - 176 -o i l a f f o r d e d 105 mg (76%) o f a c o l o r l e s s l i q u i d . A g l c a n a l y s i s (column A) o f t h i s m a t e r i a l showed t h a t i t was composed of a m i x t u r e o f (E) and ( Z ) - 3 - t r i m e t h y l s t a n n y l - 2 -b u t e n o a t e (163 and 166) i n a r a t i o o f 2:98, r e s p e c t i v e l y . T h i s m a t e r i a l e x h i b i t e d uv (MeOH) A _ : 218.5 nm (e= 9,100); i r ( f i l m ) : 1700, 1601, 1200, 772 cm" 1; 1 H nmr (CDC13> 6: 0.16 ( s , 9H, s t a n n y l m e t h y l s , J _ =55Hz), 1.25 fan-ri ( t , 3H, -OCH 2CH 3, J=7Hz), 2.12 (d, 3H, v i n y l m e t h y l , J=2Hz, J 0 =45Hz), 4.16 (q, 2H, -0CH..CH-, J=7Hz), 6.29 fan- r i — z J (q, IH, v i n y l p r o t o n , J=2Hz, J =118Hz). E x a c t mass o n — r i c a l c d . f o r CgH^C^Sn (M +-15): 263.0094; found: 263.0074 . An a n a l y t i c a l sample was o b t a i n e d by p r e p a r a t i v e t i c on s i l i c a g e l ( d e v e l o p i n g s o l v e n t : p e t r o l e u m e t h e r - e t h e r , 99:1; r f 0.32). A n a l . c a l c d . f o r C g H 1 8 0 2 S n : C 39.03, H 6.55; found: C 3 9.37, H 6.50. b) Large S c a l e To a c o l d (-78°C), v i g o r o u s l y s t i r r e d s o l u t i o n o f l i t h i u m p h e n y l t h i o ( t r i m e t h y l s t a n n y l ) c u p r a t e 7_2 (6.0 mmol) i n 50 mL o f anhydrous t e t r a h y d r o f u r a n , under a r g o n , was added a s o l u t i o n o f e t h y l 2-butynoate 160 (0.56 g, 5.0 mmol) i n 4 mL o f anhydrous t e t r a h y d r o f u r a n . The r e s u l t i n g m i x t u r e was s t i r r e d a t -78°C f o r l h , warmed t o -48°C, and s t i r r e d a t t h i s t e m p e r a t u r e f o r 4h. M e t h a n o l (0.5 mL) and e t h e r (/vl50 mL) were added and the m i x t u r e was a l l o w e d t o warm to room t e m p e r a t u r e . The r e s u l t i n g y e l l o w s l u r r y was f i l t e r e d t h r o u g h a s h o r t column of f l o r i s i l (30 g, 100-200 mesh). - 177 -The column was e l u t e d w i t h a f u r t h e r 100 mL o f e t h e r and the combined e l u a n t was c o n c e n t r a t e d . The r e s i d u a l o i l was chromatographed on 60 g o f s i l i c a g e l . E l u t i o n o f the column w i t h a 99:1 m i x t u r e o f l i g h t p e t r o l e u m e t h e r and e t h e r gave h e x a m e t h y l d i t i n . F u r t h e r e l u t i o n o f the column gave, a f t e r c o n c e n t r a t i o n o f t h e a p p r o p r i a t e f r a c t i o n s and d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 105-115°C, 20 t o r r ) o f the r e s i d u a l o i l , 0.98 g (71%) o f pure e t h y l ( Z ) - 3 -t r i m e t h y l s t a n n y l - 2 - b u t e n o a t e 166. The s p e c t r a l p r o p e r t i e s o f t h i s m a t e r i a l ( i r , "'"H nmr) were i d e n t i c a l w i t h t h o s e r e p o r t e d e a r l i e r . F u r t h e r e l u t i o n o f the column gave 29 mg (2%) o f the (E)- i s o m e r 163. P r e p a r a t i o n o f M e t h y l ( E ) - 3 - T r i m e t h y l s t a n n y l - 5 - ( t e r t -b u t y l d i m e t h y l s i l o x y ) - 2 - p e n t e n o a t e 164 F o l l o w i n g the g e n e r a l p r o c e d u r e I o u t l i n e d above, a m i x t u r e o f m e t h y l 5 - ( t e r t - b u t y l d i m e t h y l s i l o x y ) - 2 - p e n t y n o a t e 161 (121 mg, 0.50 mmol) and methanol ( 3 5 y l , 0.85 mmol) was a l l o w e d t o r e a c t w i t h l i t h i u m p h e n y l t h i o ( t r i m e t h y l s t a n n y l ) c u p r a t e 7_2 (1.00 mmol) i n t e t r a h y d r o f uran a t -100°C f o r - 178 -15 min, and a t -78°C f o r 3h. Normal workup, f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 120-135°C, 0.20 t o r r ) o f the c r u d e o i l a f f o r d e d 167 mg (82%) o f a c o l o r l e s s l i q u i d . A g l c a n a l y s i s (column A) o f t h i s m a t e r i a l showed t h a t i t was composed o f a m i x t u r e o f m e t h y l ( E ) - and (Z^ ) -3 - t r i m e t h y l s t a n n y l - 5 - ( t e r t - b u t y l d i m e t h y l s i l o x y ) - 2 - p e n t e n o a t e (164 and 167) i n a r a t i o o f 96:4, r e s p e c t i v e l y . An a n a l y t i c sample o f the former p r o d u c t was o b t a i n e d by p r e p a r a t i v e t i c on s i l i c a g e l ( d e v e l o p i n g s o l v e n t : p e t r o l e u m e t h e r - e t h e r 99:1, r f 0.18). The pure e s t e r 164 e x h i b i t e d uv (MeOH) A : 217 nm (e= 12,000); i r ( f i l m ) : 1715, 1595, 1265, max ' ' ' 780 c m - 1 ; 1 H nmr (CDC1 3) 6: 0.02 ( s , 6H, s i l y l m e t h y l s ) , 0.17 ( s , 9H, s t a n n y l m e t h y l s , J =60Hz), 3.68 ( o v e r l a p p i n g s and t , 5H, -CC^Me and -OCH 2CH 2C=, J=7Hz), 6.05 ( t , IH, v i n y l p r o t o n , J ^ l H z , J c„ =72Hz). E x a c t mass c a l c d . f o r on -ri C 1 4 H 2 9 ° 3 S i S n ( M + - 1 5 ) : 393.0908; found: 393.0906. A n a l , c a l c d . f o r C 1 5 H 3 2 0 3 S i S n : C 44.25, H 7.92; found: C 44.23, H 8.04. P r e p a r a t i o n o f M e t h y l ( Z ^ ) - 3 - T r i m e t h y l s t a n n y l - 5 - ( t e r t -b u t y l d i m e t h y l s i l o x y ) -2-pentenoate 167 MeoSn C0 9Me 3 w 2 t-BuMe2SiO MZ - 179 -F o l l o w i n g the g e n e r a l p r o c e d u r e K o u t l i n e d above, m e t h y l 5 - ( t e r t - b u t y l d i m e t h y l s i l o x y ) - 2 - p e n t y n o a t e 161 (121 mg, 0.50 mmol) was a l l o w e d t o r e a c t w i t h l i t h i u m p h e n y l t h i o -( t r i m e t h y l s t a n n y l ) c u p r a t e 7_2 (0.60 mmol) i n t e t r a h y d r o f u r a n a t -78°C f o r 15 min and a t -48°C f o r an a d d i t i o n a l 4h. The r e a c t i o n m i x t u r e was quenched w i t h m e t h a n o l . Normal workup, f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 110-122°C, 0.20 t o r r ) o f the c r u d e o i l a f f o r d e d 164 mg (81%) o f a c o l o r l e s s l i q u i d . A g l c a n a l y s i s (column A) o f t h i s m a t e r i a l showed t h a t i t was composed of a m i x t u r e o f m e t h y l ( E ) - and ( Z ) - 3 - t r i m e t h y l s t a n n y l - 5 - ( t e r t -b u t y l d i m e t h y l s i l o x y ) -2-pentenoate (164 and 167) i n a r a t i o o f 4:96, r e p s e c t i v e l y . A pure sample of the l a t t e r was o b t a i n e d by p r e p a r a t i v e t i c on s i l i c a g e l ( d e v e l o p i n g s o l v e n t : p e t r o l e u m e t h e r - e t h e r , 99:1, r f 0.26). T h i s m a t e r i a l e x h i b i t e d uv (MeOH) \ : 218 nm (e= 8,900); i r max ' ( f i l m ) : 1703, 1601, 780 cm" 1; 1 H nmr (CDC1 3) 6: 0.02 ( s , 6H, s i l y l m e t h y l s ) , 0.16 ( s , 9H, s t a n n y l m e t h y l s , J e =55Hz), 0.87 ( s , 9H, t e r t - b u t y l m e t h y l s ) , 2.63 (m, 2H, -OCH 2CH 2C=, J g n _ H = 4 7 H z ) , 3.64 ( t , 2H, -OCH 2CH 2C=, J=7Hz), 3.72 ( s , 3H, -CG^Me), 6.41 ( t , I H , v i n y l p r o t o n , J=2Hz, J S n _ H = 1 1 8 H z ) . E x a c t mass c a l c d . f o r C ^ H ^ O ^ S i S n (M +-15): 393.0908; found: 393.0891. - 180 -P r e p a r a t i o n o f E t h y l ( E ) - and (Z_)-4 , 4 - D i m e t h y l - 3 -t r i m e t h y l s t a n n y l - 2 - p e n t e n o a t e (165 and 168) t-Bu C02Et t-Bu 165 168 a) I n the Presen c e o f E t h a n o l F o l l o w i n g the g e n e r a l p r o c e d u r e J o u t l i n e d above, a m i x t u r e o f e t h y l 4 , 4 - d i m e t h y l - 2 - p e n t y n o a t e 162 (77 mg, 0.50 mmol) and e t h a n o l ( 5 0 p l , 0.8 5 mmol) was a l l o w e d t o r e a c t w i t h l i t h i u m p h e n y l t h i o ( t r i m e t h y l s t a n n y l ) c u p r a t e 7_2 (1.50 mmol) i n t e t r a h y d r o f u r a n a t -100°C f o r 15 min, and a t -78°C f o r an a d d i t i o n a l 6h. Normal workup, f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 143-156°C, 20 t o r r ) o f the crude p r o d u c t a f f o r d e d 129 mg (84%) o f a c o l o r l e s s l i q u i d . A g l c a n a l y s i s (column A) o f t h i s m a t e r i a l showed t h a t i t was composed o f a m i x t u r e o f the (E) - and (Z_) -isomers (165 and 168) i n a r a t i o o f 8:92, r e s p e c t i v e l y . A pure sample o f each isomer was o b t a i n e d by s u b j e c t i o n o f the m i x t u r e t o p r e p a r a t i v e t i c on s i l i c a g e l ( d e v e l o p i n g s o l v e n t : p e t r o l e u m e t h e r - e t h e r , 99:1). The pure e t h y l ( E ) - 4 , 4 - d i m e t h y l - 3 - t r i m e t h y l s t a n n y l - 2 -p e n t e n o a t e 165 ( r f 0.24) e x h i b i t e d uv (MeOH) A : 216 nm c max (e= 6,900); i r ( f i l m ) : 1720, 1685, 780 cm" 1; 1H nmr (CDC1 3) 6: 0.18 ( s , 9H, t e r t i a r y m e t h y l s ) , 1.28 ( t , 3H, - 181 --OCH 2CH 3, J=7Hz), 4.16 (q, 2H, -OCH 2CH 3, J=7Hz), 5.84 ( s , IH, v i n y l p r o t o n , J„ =87Hz). E x a c t mass c a l c d . f o r Sn-H C l l H 2 1 ° 2 S n ( M + _ 1 5 ) : 305.0564; found: 305.0560. A n a l . c a l c d . f o r C 1 2 H 2 4 0 2 S n : C 45.18, H 7.58; found: C 44.98, H 7.43. The pure e t h y l ( Z ) - 4 , 4 - d i m e t h y l - 3 - t r i m e t h y l s t a n n y l -2-pentenoate 168 ( r f 0.43) e x h i b i t e d one component by g l c (column A) a n a l y s i s . T h i s m a t e r i a l e x h i b i t e d uv (MeOH) A : 217 nm (e= 9,800); i r ( f i l m ) : 1 7 0 5 , 1590, max 1205, 780 cm" 1; 1 H nmr (CDC1 3) 6: 0.20 ( s , 9H, s t a n n y l m e t h y l s , J S n _ H = 5 4 H z ) , 1.12 ( s , 9H, t e r t i a r y m e t h y l s ) , 1.26 ( t , 3H, -OCH 2CH 3, J- 7 H z ) , 4.18 (q, 2H, -OCH 2CH 3, J=7Hz), 6.35 ( s , IH, v i n y l p r o t o n , J 0 =126Hz). E x a c t sn—r i mass c a l c d . f o r C ^ H ^ C ^ S n (M +-15) : 305.0564; fo u n d : 305.0555. b) A t -48°C F o l l o w i n g the g e n e r a l p r o c e d u r e L o u t l i n e d above, e t h y l 4 , 4 - d i m e t h y l - 2 - p e n t y n o a t e 162 (77 mg, 0.50 mmol) was a l l o w e d t o r e a c t w i t h l i t h i u m p h e n y l t h i o ( t r i m e t h y l s t a n n y l ) c u p r a t e 7_2 (0.70 mmol) i n t e t r a h y d r o f uran a t -78°C f o r 15 min, and a t -48°C f o r an a d d i t i o n a l 4h. The r e a c t i o n m i x t u r e was quenched w i t h e t h a n o l . Normal workup, f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 145-157°C, 20 t o r r ) o f the c r u d e o i l a f f o r d e d 131 mg (86%) o f a c o l o r l e s s l i q u i d . A g l c a n a l y s i s (column A) o f t h i s m a t e r i a l showed t h a t i t was composed o f a m i x t u r e o f t h e (E) - and (Z^)-isomers 165 and 168 i n a r a t i o o f 2:98, r e s p e c t i v e l y . The i d e n t i t y - 182 -of the (Z)-isomer 168 was c o n f i r m e d by i t s s p e c t r a l d a t a . R e d u c t i o n o f E t h y l ( Z ) - 4 , 4 - D i m e t h y l - 3 - t r i m e t h y l -s t a n n y l - 2 - p e n t e n o a t e 16 8 To a c o l d ( 0 W C ) , v i g o r o u s l y s t i r r e d m i x t u r e o f l i t h i u m aluminum h y d r i d e (6.0 mg, 0.13 mmol) and e t h a n o l ( 7 . 6 y l , 0.13 mmol) i n 2 mL o f anhydrous e t h e r , under an atmosphere of a r g o n , was added, d r o p w i s e , a s o l u t i o n o f the u n s a t u r a t e d e s t e r 168 (32 mg, 0.10 mmol) i n 0.5 mL o f anhydrous e t h e r . A f t e r the r e s u l t i n g m i x t u r e had been s t i r r e d a t 0°C f o r 3 0 min, i t was warmed t o room t e m p e r a t u r e , and s t i r r e d f o r an a d d i t i o n a l p e r i o d o f l h . Sodium s u l f a t e d e c a h y d r a t e was added and the m i x t u r e was s t i r r e d u n t i l a w h i t e g r a n u l a r p r e c i p i t a t e had formed. The i n o r g a n i c s a l t s were removed by f i l t r a t i o n and washed w i t h s e v e r a l p o r t i o n s o f h o t e t h e r . The combined f i l t r a t e s were c o n c e n t r a t e d under reduced p r e s s u r e . D i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 65-75°C, 0.07 t o r r ) o f the r e s i d u a l o i l a f f o r d e d 24 mg (87%) o f ( Z ) - 4 , 4 - d i m e t h y l - 3 - t r i m e t h y l s t a n n y l - 2 - p e n t e n - l - o l 170. T i c and g l c a n a l y s e s ( s i l i c a g e l and column A, r e s p e c t i v e l y ) showed the pr e s e n c e o f one component. T h i s m a t e r i a l t-Bu 170 o - 183 -e x h i b i t e d i r ( f i l m ) : 3310, 780 cm" 1; 1 H nmr (CDC1 3) <5: 0.23 ( s , 9H, s t a n n y l m e t h y l s , J c =52Hz), 1.06 ( s , 9H, t e r t - b u t y l m e t h y l s ) , 1.26 (broad s, IH, -CH 2OH), 4.14 ( u n r e s o l v e d m, 2H, -CH 2OH), 6.17 ( t , IH, v i n y l p r o t o n , J=7Hz, J" S n_ H=148Hz) . E x a c t mass c a l c d . f o r C gH 1 9OSn (M +-15) : 263.0458; found: 263.0455. P r e p a r a t i o n o f E t h y l ( E ) - 3 - T r i m e t h y l s t a n n y l a c r y l a t e 174 3 4 MeoSn 174 C02Et To a c o l d (-100°C), s t i r r e d s o l u t i o n o f l i t h i u m p h e n y l t h i o ( t r i m e t h y l s t a n n y l ) c u p r a t e 7_2 (1.1 mmol) i n 10 mL o f anhydrous t e t r a h y d r o f u r a n , under an atmosphere of a r g o n , was s e q u e n t i a l l y added anhydrous e t h a n o l ( 1 7 5 y l , 3.0 mmol) and a s o l u t i o n (THF, ^ 1 mL) o f e t h y l p r o p i o l a t e 173 (98 mg, 1.0 mmol). The r e s u l t i n g m i x t u r e was s t i r r e d a t -100°C f o r l h . E t h e r (^30 mL) was added and the m i x t u r e was a l l o w e d t o warm t o room t e m p e r a t u r e . Normal workup (as o u t l i n e d i n g e n e r a l p r o c e d u r e I ) a f f o r d e d a p a l e y e l l o w l i q u i d . A g l c a n a l y s i s (column A) o f t h i s m a t e r i a l showed t h a t i t was composed o f a m i x t u r e o f e t h y l ( E ) - and ( Z ) -3 - t r i m e t h y l s t a n n y l a c r y l a t e (174 and 175) , a l o n g w i t h e t h y l - 184 -2 - t r i m e t h y l s t a n n y l a c r y l a t e 176, i n a r a t i o o f 90:3:7, r e s p e c t i v e l y . Other minor u n i d e n t i f i e d p r o d u c t s were a l s o p r e s e n t . T h i s m a t e r i a l was s u b j e c t e d t o p r e p a r a t i v e t i c on s i l i c a g e l ( d e v e l o p i n g s o l v e n t : l i g h t p e t r o l e u m e t h e r -e t h e r , 9 9:1). D i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 83-91°C, 25 t o r r ) o f the p u r i f i e d p r o d u c t ( r f 0.18) a f f o r d e d 147 mg (56%) o f e t h y l ( E ) - 3 - t r i m e t h y l s t a n n y l a c r y l a t e 174 contam-i n a t e d w i t h a s m a l l amount (as d e t e r m i n e d by "'"H nmr 34 a n a l y s i s ) o f the a-isomer 176. T h i s m a t e r i a l e x h i b i t e d uv (MeOH) A : 212.5 nm (e= 11,800); i r ( f i l m ) : 1720, max ' 1597, 1215, 780 cm" 1; 1 H nmr (60 MHz) (CDCl-j) 6: 0.14 (s , 9H, s t a n n y l m e t h y l s , J c =54Hz), 1.24 ( t , 3H, -OCH-CH-, £>n—ri z. — j J=7Hz), 4.17 (q, 2H, -OCH 2CH 3, J=7Hz), 5.93 and 6.85 (d,d, ^O.lH each, g e m i n a l o l e f i n i c p r o t o n s o f 176, J^ 3 H z ) , 6.27 (d, ^0.9H, C-2 o l e f i n i c p r o t o n o f 174, J=19Hz, Ja =63Hz), bn—ri 7.73 (d, ^ 0.9H, C-3 o l e f i n i c p r o t o n o f 17_4, J=19Hz, J C r , =70Hz) . E x a c t mass c a l c d . f o r C nH n -0 0Sn (M +-15) : bn - r i 7 13 2 248.9937; found: 248.9940. P r e p a r a t i o n o f E t h y l ( E ) - 3 - T r i - n - b u t y l s t a n n y l a c r y l a t e 177 n-Bi^Sn 1 7 2 C 0 2 E t - 185 -To a cold (-100 C) , vigorously s t i r r e d solution of lithium phenylthio(tri-n-butylstannyl)cuprate 7_3 (1.10 mmol) in 10 mL of anhydrous tetrahydrofuran, under an atmosphere of argon, was sequentially added ethanol (175yl, 3.00 mmol) and a solution (THF, %1 mL) of ethyl propiolate 173 (98 mg, 1.00 mmol). The r e s u l t i n g mixture was s t i r r e d at -100°C for l h . Ether (^ 30 mL) was added and the mixture was allowed to warm to room temperature. The re s u l t i n g yellow slurr y was f i l t e r e d through a short column (^10g) of s i l i c a g e l . The column was eluted with a further 50 mL of ether and the eluant was combined. Removal of the solvent afforded a yellow o i l . Glc (column A) and 1H nmr analysis of this material showed that i t was composed mainly of the (E)-isomer 177, along with a small amount of the (Z)-isomer 178 and ethyl 2-tri-n-butylstannylacrylate 179.* This material was p u r i f i e d by preparative t i c on s i l i c a gel (developing solvent: petroleum ether-ether, 99:1). D i s t i l l a t i o n (air-bath temperature 135-148°C, 0.07 torr) of the o i l thus obtained (rf 0.22) afforded 230 mg (59%) of ethyl (E)-3-tri-n-butylstannylacrylate 177. This material was ^95% pure as determined by glc analysis (column A) and i t exhibited uv (MeOH) A : 226 nm (e= 6,600); i r ( f i l m ) : * Two weak signals at 6 5.88 and 66.86 i n the H nmr of the crude material indicated the presence of 179. - 186 -1721, 1595, 1213 cm" 1; 1H nmr (CDC1 3) 6: 0.80-1.06 (m, 15H, -Sn (CH 2CH 2CH 2CH_ 3) ) , 1.18-1.62 (m, 12H, -Sn (CH2CH_2CH_2CH3) 1.31 ( t , 3H, -OCH2CH_3, J=7Hz), 4.21 (q, 2H, -OCH 2CH 3, J=7Hz) , 6.30 (d, IH, C-2 o l e f i n i c p r o t o n , J=19Hz, J S n _ H = 6 0 H z ) . E x a c t  mass c a l c d . f o r C ^ H ^ O ^ n (M +-57): 333.0877; found: 333.0879. 34 P r e p a r a t i o n o f E t h y l ( Z ) - 3 - T r i m e t h y l s t a n n y l a c r y l a t e 175 Me3Sn^ ^C02Et 175 To a c o l d (-48°C), s t i r r e d s o l u t i o n o f Me 3SnCu'LiBr*SMe 2  94 (0.65 mmol) i n 5 mL o f anhydrous t e t r a h y d r o f u r a n , under arg o n , was added a s o l u t i o n (THF, ^ 1 mL) o f e t h y l (Z_)-3-t o s y l o x y a c r y l a t e 180* (135 mg, 0.50 mmol). A f t e r the r e a c t i o n m i x t u r e had been s t i r r e d a t -48°C f o r 2h, a t -20°C f o r l h , and a t room te m p e r a t u r e f o r l h i t was quenched w i t h pH 8 s a t u r a t e d aqueous ammonium c h l o r i d e . Normal workup (as o u t l i n e d e a r l i e r i n g e n e r a l p r o c e d u r e B) a f f o r d e d a y e l l o w o i l . A g l c a n a l y s i s (column A) o f t h i s m a t e r i a l showed t h a t i t was composed o f a - m i x t u r e o f the ( E ) - and (Z_)- e s t e r s (174 and 175) i n a r a t i o o f 3:97, r e s p e c t i v e l y . * I am v e r y g r a t e f u l t o Dr G. S. Bates and Mr. S. Ramaswamy f o r a generous sample o f t h i s compound. - 187 -Other minor u n i d e n t i f i e d p r o d u c t s as w e l l as h e x a m e t h y l d i t i n were a l s o p r e s e n t . T h i s m a t e r i a l was chromatographed on 2.7g o f s i l i c a g e l . E l u t i o n ' o f the column w i t h l i g h t p e t r o l e u m e t h e r (^10 mL) gave h e x a m e t h y l d i t i n . F u r t h e r e l u t i o n o f the column w i t h e t h e r (^ 8 mL), f o l l o w e d by removal of the s o l v e n t from the a p p r o p r i a t e f r a c t i o n s and d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 81-91°C, 25 t o r r ) o f the r e s i d u a l o i l , gave 80 mg (61%) o f e t h y l (55)-3-t r i m e t h y l s t a n n y l a c r y l a t e 175. A g l c a n a l y s i s (column A) i n d i c a t e d t h i s m a t e r i a l was >97% pure and i t e x h i b i t e d uv (MeOH) s h o u l d e r 214 nm (e = 6,900); i r ( f i l m ) : 1710, 1590, 1210, 780 c m - 1 ; 1 H nmr (CDC1 3) 6: 0.19 ( s , 9H, s t a n n y l m e t h y l s ) 1.31 ( t , 3H, -OCH2CH_3, J=7Hz) , 4.25 (q, 2H, -OCH 2CH 3, J=7Hz), 6.72 (d, IH, C-2 o l e f i n i c p r o t o n , J=12Hz, J S n _ H = 1 2 l H z ) , 7.17 (d, IH, C-3 o l e f i n i c p r o t o n , J-12Hz, J _ =68Hz) . E x a c t mass c a l c d . f o r C_,H, _,0~Sn o n - n / i j z (M +-15): 248.9938; fou n d : 248.9937. P r e p a r a t i o n o f E t h y l ( Z ) - 3 - T r i - n - b u t y l s t a n n y l a c r y l a t e 178 n-BuoSn C02Et 178 - 188 -To a c o l d (-48°C), s t i r r e d s o l u t i o n o f n-Bu 3SnCu'LiBr•SMe 2  181 (0.60 mmol) i n 5 mL o f anhydrous t e t r a h y d r o f u r a n , under an atmosphere o f arg o n , was added, a s o l u t i o n o f e t h y l ( Z ^ ) - 3 - t o s y l o x y a c r y l a t e 180 (135 mg, 0.50 mmol) i n 1 mL of anhydrous hexamethylphosphoramide. The r e a c t i o n m i x t u r e was s t i r r e d a t -48°C f o r 2h, -20°C f o r l h , and a t room temp e r a t u r e f o r l h . S a t u r a t e d pH 8 aqueous ammonium c h l o r i d e (^ 2 mL) and e t h e r (/^ 30 mL) were added and the r e s u l t i n g m i x t u r e was s t i r r e d f o r s e v e r a l m i n u t e s . The e t h e r l a y e r was s e p a r a t e d , washed w i t h pH 8 s a t u r a t e d aqueous ammonium c h l o r i d e and w a t e r , and d r i e d o v er anhydrous magnesium s u l f a t e . Removal o f the s o l v e n t a f f o r d e d a y e l l o w o i l , w hich was chromatographed on 2.7 g o f s i l i c a g e l . E l u t i o n o f the column w i t h p e t r o l e u m e t h e r (>10 mL) gave a m i x t u r e o f t e t r a - n - b u t y l t i n and hexa-n-b u t y l d i t i n . F u r t h e r e l u t i o n o f the column w i t h e t h e r (^ 8 mL) f o l l o w e d by c o n c e n t r a t i o n o f the a p p r o p r i a t e f r a c t -i o n s and d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 138-147°C, 0.10 t o r r ) o f the r e s i d u a l o i l gave 122 mg (63%) o f e t h y l ( Z ) - 3 - t r i - n - b u t y l s t a n n y l a c r y l a t e 178. A g l c a n a l y s i s (column A) showed t h a t t h i s m a t e r i a l was ^98% p u r e . T h i s m a t e r i a l e x h i b i t e d uv (MeOH) X : 228 nm (e = 3,500); max ' i r ( f i l m ) : 1697, 1577, 1192 cm" 1; 1 H nmr (CDC1 3) 6: 0.76-1.06 (m, 15H, -Sn (CH 2CH 2CH 2CH 3) 3 ) , 1.18-1.58 (m, 12H, -Sn (CH 2CH_ 2CH 2CH 3 - 189 -( t , 3H, -OCH 2CH 3, J=7Hz), 4.22 (q, 2H, -OCH 2CH 3, J=7Hz), 6.74 (d, IH, C-2 o l e f i n i c p r o t o n , J=13Hz,.J c =110Hz), 7.15 (d, IH, C-3 o l e f i n i c p r o t o n , J=13Hz, J c = 6 l H z ) . Sn~ H E x a c t mass c a l c d . f o r C 1 3 H 2 5 0 2 S n (M +-57): 333.0877; Found: 333.0882. R e d u c t i o n o f E t h y l ( E ) - 3 - T r i m e t h y I s t a n n y l - 2 - b u t e n o a t e 163 MegSn MegSn CHO / CH20H 188 189 To a c o l d (-127°C), v i g o r o u s l y s t i r r e d s o l u t i o n o f the u n s a t u r a t e d e s t e r 163 (1.40 g, 5.06 mmol) i n 30 mL o f anhydrous pentane, under an atmosphere o f a r g o n , was added d r o p w i s e over a p e r i o d o f 10 min, a s o l u t i o n o f d i i s o b u t y l -aluminum h y d r i d e i n hexane (5.06 mL, 5.06 mmol). The r e s u l t i n g m i x t u r e was s t i r r e d at-127°C f o r l h . S a t u r a t e d aqueous ammonium c h l o r i d e (^0.3 mL) and e t h e r (60 mL) were added. The r e s u l t i n g m i x t u r e was a l l o w e d t o warm t o room temp e r a t u r e and was then f i l t e r e d t h r o u g h a s h o r t column o f f l o r i s i l ( l O g , 100-200 mesh). The column was e l u t e d w i t h an a d d i t i o n a l 6 0 mL o f e t h e r and the combined e l u a n t was c o n c e n t r a t e d by d i s t i l l a t i o n ( a t atmos. p r e s s u r e ) The r e s i d u e was chromatographed on 50g o f s i l i c a g e l . - 190 -E l u t i o n o f the column w i t h a 95:5 m i x t u r e o f l i g h t p e t r o l e u m e t h e r and e t h e r gave, a f t e r d i s t i l l a t i o n ( a i r b a t h t e m p e r a t u r e 85-95°C, 25 t o r r ) o f the m a t e r i a l o b t a i n e d from the appro-p r i a t e f r a c t i o n s , 1.01 g (86%) o f ( E ) - 3 - t r i m e t h y l s t a n n y l - 2 -b u t e n a l 188. T i c and g l c a n a l y s e s ( s i l i c a g e l and column A, r e s p e c t i v e l y ) showed the pr e s e n c e o f one component. T h i s m a t e r i a l e x h i b i t e d i r ( f i l m ) : 2840, 2740, 1675, 1155, 780 c m - 1 ; 1 H nmr (CDC1 3) 6: 0.19 ( s , 9H, s t a n n y l m e t h y l s , J _ =54Hz), 2.46 (d, 3H, v i n y l m e t h y l , J=2Hz, J _ =48Hz), on-ri on—ri 6.21 (d o f q, IH, v i n y l p r o t o n , J=2Hz, J'=7Hz, =68Hz), o n - r i 10.05 (d, IH, -CHO, J'=7Hz). E x a c t mass c a l c d . f o r C 6 H l l ° 2 S n ( M + - 1 5 ) : 234.9781; found: 234.9803. F u r t h e r e l u t i o n o f the column w i t h a 9:1 m i x t u r e o f l i g h t p e t r o l e u m e t h e r and e t h e r gave, a f t e r c o n c e n t r a t i o n o f t h e a p p r o p r i a t e f r a c t i o n s and d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 90-98°C, 25 t o r r ) of the r e s i d u a l o i l , 58 mg (5%) o f ( E ) - 3 - t r i m e t h y I s t a n n y l - 2 - b u t e n - l - o l 189 . 3 4 T i c and g l c a n a l y s e s ( s i l i c a g e l and column A, r e s p e c t i v e l y ) showed the pr e s e n c e o f one component. T h i s m a t e r i a l e x h i b i t e d i r ( f i l m ) : 3220, 770 cm" 1; 1 H nmr (CDC1 3) S: 0.12 ( s , 9H, s t a n n y l m e t h y l s , J c =52Hz), 1.45 (broad s, o n - r i IH, -CH 2OH), 1.90 (q, 3H, v i n y l m e t h y l , J=2Hz, J g n _ H = 5 0 H z ) . 4.26 (broad d, 2H, -CH^OH, J' ^ 6 H z ) , 5.80 ( o v e r l a p p e d t o f q, IH, v i n y l p r o t o n , J=2Hz, J'=6Hz, Ja =78Hz). E x a c t mass on—ti c a l c d . f o r C 6H 1 3OSn ( M + - l 5 ) : 221.0003; f o u n d : 221.0011. - 191 -O x i d a t i o n o f ( E ) - 3 - T r i m e t h y 1 s t a n n y l - 2 - b u t e n - l - o l 189 To a s t i r r e d s u s p e n s i o n o f barium manganate (416 mg, 1.62 mmol) i n 3 mL o f d r y d i c h l o r o m e t n a n e , under a r g o n , was added a s o l u t i o n o f t h e a l l y l i e a l c o h o l 189 (28 mg, 0.12 mmol) i n 1 mL o f d r y d i c h l o r o m e t h a n e . The r e s u l t i n g m i x t u r e was s t i r r e d a t room temp e r a t u r e f o r 4h. E t h e r (15 mL) and c e l i t e (^100 mg) were added and t h e e n t i r e volume o f l i q u i d was f i l t e r e d t h r o u g h f l o r i s i l (3g, 100-200 mesh). The column was e l u t e d w i t h a f u r t h e r 20 mL o f e t h e r and t h e combined e l u a n t was c o n c e n t r a t e d ( d i s t i l l -a t i o n a t a t m o s p h e r i c p r e s s u r e ) . D i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 85-93, 20 t o r r ) o f the crude p r o d u c t i n t o a r e c e i v e r c o o l e d t o -78°C a f f o r d e d 24 mg (87%) o f pure (by t i c and g l c a n a l y s e s ) ( E ) - 3 - t r i m e t h y l s t a n n y l - 2 - b u t e n a l 188. The s p e c t r a l p r o p e r t i e s o f t h i s m a t e r i a l were i d e n t i c a l w i t h t h o s e r e p o r t e d above. R e d u c t i o n o f E t h y l ( Z ) - 3 - T r i m e t h y l s t a n n y l - 2 - b u t e n o a t e 166 190 191 To a c o l d (-127°C), v i g o r o u s l y s t i r r e d s o l u t i o n o f the - 192 -u n s a t u r a t e d e s t e r 166 (0.90 g, 3.21 mmol) i n 30 mL o f anhydrous pentane, under a r g o n , was added d r o p w i s e over a p e r i o d o f 10 min a s o l u t i o n o f d i i s o b u t y l a l u m i n u m h y d r i d e i n hexane (3.21 mL, 3.21 mmol). The r e s u l t i n g m i x t u r e was s t i r r e d a t -127°C f o r l h . S a t u r a t e d aqueous ammonium c h l o r i d e (^0.3 mL) and e t h e r (60 mL) were added. The r e a c t i o n m i x t u r e was a l l o w e d t o warm t o room t e m p e r a t u r e . Anhydrous sodium s u l f a t e was added and the r e s u l t a n t m i x t u r e was f i l t e r e d t h r o u g h a s h o r t column o f f l o r i s i l (8 g, 100-200 mesh). The column was f u r t h e r e l u t e d w i t h an a d d i t i o n a l 60 mL o f e t h e r . The combined e l u a n t was c o n c e n t r a t e d by d i s t i l l a t i o n ( at a t m o s p h e r i c p r e s s u r e ) . The r e s i d u e was chromatographed on 40 g o f s i l i c a g e l . E l u t i o n o f the column w i t h a 95:5 m i x t u r e o f l i g h t p e t r o l e u m e t h e r and e t h e r gave, a f t e r d i s t i l l a t i o n ( a i r - b a t h t e mperature 83-95°C, 20 t o r r ) o f the m a t e r i a l from the a p p r o p r i a t e f r a c t i o n s , 0.74 g (82%) o f ( Z , ) - 3 - t r i m e t h y l s t a n n y l -2 - b u t e n a l 190. T i c and g l c a n a l y s e s ( s i l i c a g e l and column A, r e s p e c t i v e l y ) showed the p r e s e n c e o f one major component. T h i s m a t e r i a l e x h i b i t e d i r ( f i l m ) : 2825, 2720, 1680, 1563, 770 cm" 1; 1 H nmr (CDCl-j) 6: 0.22 ( s , 9H, s t a n n y l m e t h y l s , J S n _ H = 5 5 H z ) , 2.21 (d, 3H, v i n y l m e t h y l , J=2Hz, J g n _ H = 4 3 H z ) , 6.70 (d o f q, IH, v i n y l p r o t o n , J=2Hz, J'=6Hz, J c =118Hz), bn~ r i 9.54 (d, IH, -CHO, J'=6Hz). E x a c t mass c a l c d . f o r C 6 H l l ° 2 S n ( M + ~ 1 5 ) : 234.9781; fou n d : 234.9776. - 193 -F u r t h e r e l u t i o n o f the column w i t h a 9:1 m i x t u r e o f l i g h t p e t r o l e u m e t h e r and e t h e r gave, a f t e r d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 81-89°C, 25 t o r r ) o f the m a t e r i a l o b t a i n e d from the a p p r o p r i a t e f r a c t i o n s , 52 mg (7%) o f ( Z ) - 3 - t r i m e t h y l s t a n n y l - 2 - b u t e n - l - o l 191. T i c and g l c a n a l y s e s ( s i l i c a g e l and column A, r e s p e c t i v e l y ) showed the p r e s e n c e o f one major component. T h i s m a t e r i a l e x h i b i t e d i r ( f i l m ) : 3220, 770 c m - 1 ; 1 H nmr (CDC1 3, t r a c e D 20 added) 6: 0.13 ( s , 9H, s t a n n y l m e t h y l s , J S n _ H = 5 3 H z ) , 1.92 (d, 3H, v i n y l m e t h y l , J=2Hz, J„ =46Hz), 4.05 (broad d, bn—n 2H, -CH 2OH, J'=6Hz), 6.23 ( t o f q, IH, v i n y l p r o t o n , J=2Hz, J'=6Hz, J _ =134Hz) E x a c t mass c a l c d . f o r C CH,,OSn (M +-15): Sn-H 6 13 221.0003; found 221.0017. O x i d a t i o n o f ( Z _ ) - 3 - T r i m e t h y l s t a n n y l - 2 - b u t e n - l - o l 191 To a s t i r r e d s u s p e n s i o n o f ba r i u m manganate (34 2 mg, 1.3 3 mmol) i n 3 mL o f anhydrous d i c h l o r o m e t h a n e , under ar g o n , was added a s o l u t i o n ( C H 2 C 1 2 , 1 mL) o f the a l l y l i c a l c o h o l 191 (23 mg, 0.10 mmol). The r e s u l t i n g m i x t u r e was s t i r r e d a t room tem p e r a t u r e f o r 8h. E t h e r (15 mL) and c e l i t e (^100 mg) were added and t h e m i x t u r e was f i l t e r e d t h r o u g h f l o r i s i l (3g, 100-200 mesh). The column was e l u t e d w i t h a f u r t h e r 10 mL o f e t h e r and the s o l v e n t was removed ( d i s t i l l a t i o n a t a t m o s p h e r i c p r e s s u r e ) from the combined e l u a n t . D i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 85-98°C, 20 t o r r ) - 194 -of the r e s i d u a l o i l i n t o a r e c e i v e r c o o l e d t o -78 C a f f o r d e d 17 mg (73%) o f pure (by t i c and g l c a n a l y s e s ) (Z_)-3-t r i m e t h y l s t a n n y l - 2 - b u t e n a l 190. The s p e c t r a l p r o p e r t i e s o f t h i s m a t e r i a l were i d e n t i c a l w i t h t h o s e r e p o r t e d e a r l i e r . P r e p a r a t i o n o f ( E ) - 4 - T r i m e t h y l s t a n n y l - l , 3 - p e n t a d i e n e 184 To a s t i r r e d s o l u t i o n o f m e t h y l e n e t r i p h e n y l p h o s p h o r a n e (5.3 mmol) i n 20 mL o f anhydrous t e t r a h y d r o f u r a n , under argon, was added a s o l u t i o n o f ( E ) - 3 - t r i m e t h y l s t a n n y l - 2 -b u t e n a l 188 (0.95 g, 4.1 mmol) i n 3 mL o f d r y t e t r a h y d r o -f u r a n . The r e a c t i o n m i x t u r e was s t i r r e d a t room t e m p e r a t u r e f o r 2h. L i g h t p e t r o l e u m e t h e r (40 mL) was added and the s l u r r y was f i l t e r e d t h r o u g h a s h o r t column o f f l o r i s i l ( l O g , 100-200 mesh). The column was e l u t e d w i t h an a d d i t i o n a l 40 mL o f l i g h t p e t r o l e u m e t h e r and the e l u a n t was combined. Removal o f the s o l v e n t ( d i s t i l l a t i o n a t a t m o s p h e r i c p r e s s u r e ) , f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 73-80°C, 20 t o r r ) o f the r e s i d u a l o i l , a f f o r d e d 0.69 g (74%) o f ( E ) - 4 - t r i m e t h y l s t a n n y l - l , 3 - p e n t a d i e n e 184. T i c and g l c a n a l y s e s ( s i l i c a g e l and column A, r e s p e c t i v e l y ) 'C 'a 184 showed the p r e s e n c e o f one component. T h i s m a t e r i a l e x h i b i t e d uv (MeOH) : 236 nm (e= 22,700); i r ( f i l m ) : 3080, 1620, 1575, 987, 770 cm" 1; 1H nmr (CDC13> 6: 0.16 ( s , 9H, s t a n n y l m e t h y l s , J g n _ H = 5 3 H z ) , 2.02 (d, 3H, v i n y l m e t h y l , J=2Hz, J e = 5 l H z ) , 5.10 (d o f d, IH, H , J ,=2Hz, bn-n a ao J a c = 1 0 H z ) , 5.17 (d o f d, IH, H b, J a b = 2 H z , J b c = 1 6 H z ) , 6.16 (d o f q, I H , H d, J c d=10.5Hz, J'=2Hz), 6.76 (m, IH, H , J a c = 1 0 H z , J b c = 1 6 H z , J c d = 1 0 . 5 H z ) . E x a c t mass c a l c d . f o r C g H 1 6Sn: 232.0274; found: 232.0281. P r e p a r a t i o n o f ( Z ) - 4 - T r i m e t h y l s t a n n y l - l , 3 - p e n t a d i e n e 185 MegSn 185 To a s t i r r e d s o l u t i o n o f m e t h y l e n e t r i p h e n y l p h o s p h o r a n e (5.1 mmol) i n 20 mL o f anhydrous t e t r a h y d r o f u r a n , under a r g o n , was added a s o l u t i o n o f ( Z ) - 3 - t r i m e t h y l s t a n n y l - 2 -b u t e n a l 190 (0.90 g, 3.9 mmol) i n 2 mL o f d r y t e t r a h y d r o -f u r a n . The r e s u l t i n g m i x t u r e was s t i r r e d a t room te m p e r a t u r e f o r 2h. L i g h t p e t r o l e u m e t h e r (100 mL) was added and the r e s u l t a n t s l u r r y was f i l t e r e d t h r o u g h a s h o r t column o f f l o r i s i l ( l O g , 100-200 mesh). The column was e l u t e d w i t h an a d d i t i o n a l 50 mL o f l i g h t p e t r o l e u m e t h e r and the e l u a n t - 196 -was combined. Removal o f the s o l v e n t ( d i s t i l l a t i o n a t a t m o s p h e r i c p r e s s u r e ) , f o l l o w e d by d i s t i l l a t i o n ( a i r -b a t h t e m p e r a t u r e 69-78°C, 20 t o r r ) o f the r e s i d u a l o i l a f f o r d e d 0.64 g (72%) o f ( Z ) - d i e n e 185. T i c and g l c a n a l y s e s ( s i l i c a g e l and column A, r e s p e c t i v e l y ) showed the p r e s e n c e o f one component. T h i s m a t e r i a l e x h i b i t e d uv (MeOH) A : 235.5 nm (e= 22,200); i r ( f i l m ) : 3075, max ' 1620, 1575, 980, 900, 770 cm" 1; 1 H nmr (CDC1 3) 6: 0.25 ( s , 9H, s t a n n y l m e t h y l s , J g n _ H = 5 3 H z ) , 2.02 (d, 3H, v i n y l m e t h y l , J=2Hz, J e =48Hz), 5.04 (d o f d, IH, H , J , ^ l H z , bn—ri a ao J a c = 9 H z ) , 5.10 (d o f d, IH, H b, J ^ l H z , J b c=16Hz) , 6.36 (m, IH, H c, J a c = 9 H z , J b c = 1 6 H z , J c d = 1 0 H z ) , 6.65 (d of q, IH, H d ' J c d = 1 0 H Z / J ' = 2 H z ) • E x a c t mass c a l c d . f o r C g H ^ S n : 232.0274; found: 232.0271. G e n e r a l P r o c e d u r e M: P r e p a r a t i o n o f ( E ) - and (Z)- 4 -L i t h i o - 1 , 3 - p e n t a d i e n e s (187 and 186) and T h e i r R e a c t i o n w i t h E l e c t r o p h i l e s 187 186 To a c o l d (-78°C), s t i r r e d s o l u t i o n o f e i t h e r ( E ) - o r ( Z ) - 4 - t r i m e t h y l s t a n n y l - l , 3 - p e n t a d i e n e (184 or 185) (58 mg, 0.25 mmol) i n 4 mL o f anhydrous t e t r a h y d r o f u r a n , under an - 197 -atmosphere o f a r g o n , was added a s o l u t i o n o f m e t h y l l i t h i u m i n e t h e r (0.30 mmol). The r e s u l t i n g m i x t u r e was s t i r r e d a t -78°C f o r 10 min. A y e l l o w s o l u t i o n c o n t a i n i n g 0.25 mmol o f the c o r r e s p o n d i n g 4 - l i t h i o - l , 3 - p e n t a d i e n e r e s u l t e d . A s o l u t i o n o f the a p p r o p r i a t e e l e c t r o p h i l e (0.33 mmol) i n anhydrous t e t r a h y d r o f u r a n (^0.4 mL) was added. When the e l e c t r o p h i l e was an a l k y l h a l i d e , the r e a c t i o n m i x t u r e was s t i r r e d a t -7 8°C f o r l h , warmed t o room tem p e r a t u r e over a p e r i o d o f l h , and then quenched w i t h s a t u r a t e d aqueous ammonium c h l o r i d e . W i t h c a r b o n y l e l e c t r o p h i l e s , the r e a c t i o n m i x t u r e was s t i r r e d a t -78°C f o r l h , and t r e a t e d a t t h i s t e m p e r a t u r e w i t h s a t u r a t e d aqueous ammonium c h l o r i d e . The r e s u l t i n g m i x t u r e s were d i l u t e d w i t h e t h e r (25 mL), washed w i t h b r i n e , and d r i e d o v e r anhydrous magnesium s u l f a t e . Removal o f the s o l v e n t , f o l l o w e d by p u r i f i c a t i o n o f the r e s i d u a l o i l gave the f i n a l p r o d u c t . P r e p a r a t i o n o f ( E ) - 4 - M e t h y l - l , 3 - d o d e c a d i e n e 194 F o l l o w i n g the g e n e r a l p r o c e d u r e M o u t l i n e d above, 0.2 5 mmol o f ( Z ) - 4 - l i t h i o - l , 3-pentadiene 18_6 was a l l o w e d t o r e a c t w i t h 1-bromooctane (64 mg, 0.33 mmol) i n t e t r a h y d r o f u r a n 194 - 198 -a t 78°C f o r l h , and a t room te m p e r a t u r e f o r l h . Normal workup a f f o r d e d a y e l l o w o i l , w h i c h was p u r i f i e d by p r e p -a r a t i v e t i c on 12% (w/w) s i l v e r n i t r a t e - s i l i c a g e l ( d e v e l -o p i n g s o l v e n t : p e t r o l e u m e t h e r - e t h e r , 98:2). D i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 138-149°C, 20 t o r r ) o f the o i l thus o b t a i n e d a f f o r d e d 32 mg (71%) o f the d i e n e 194. A g l c a n a l y s i s (column A) showed the p r e s e n c e o f one component. T h i s m a t e r i a l e x h i b i t e d i r ( f i l m ) : 3070, 3040, 1645, 1598, 987, 900 cm" 1; 1 H nmr (CDC1 3) 6: 0.87 (m, 3H, t e r m i n a l m e t h y l ) , 1.14-1.50 (broad u n r e s o l v e d s i g n a l , 12H, non-a l l y l i c m e t h y l e n e s ) , 1.74 (d, 3H, v i n y l m e t h y l , CK1.5Hz), 2.05 (broad t , 2H, a l l y l i c m e t h y l e n e ) , 4.96 (d o f d, IH, H , J ,=2Hz, J =10Hz) , 5.08 (d o f d, IH, H, , J ,=2Hz, 3. cl.D c l C D cLD J b c = 1 6 . 5 H z ) , 5.84 (broad d, IH, H d, J d = l l H z ) , 6.60 (m, IH, H , J 10Hz, J, =16.5Hz, J , = l l H z ) . E x a c t mass C c l C D C C Q -c a l c d . f o r C 1 3 H 2 4 : 180.1878; fo u n d : 180.1878. P r e p a r a t i o n o f ( E ) - 6 - ( 2 - C y c l o p e n t e n y l ) - 4 - m e t h y 1 - 1 , 3 - h e x a d i e n e 195 - 199 -F o l l o w i n g t h e g e n e r a l p r o c e d u r e M o u t l i n e d above, 0.25 mmol o f ( Z ) - 4 - l i t h i o - l , 3 - p e n t a d i e n e 186 was a l l o w e d t o r e a c t w i t h l - b r o m o - 2 - ( 2 - c y c l o p e n t e n y l ) e t h a n e (58 mg, 0.33 mmol) i n t e t r a h y d r o f u r a n a t -78°C f o r l h , and a t room t e m p e r a t u r e f o r l h . Normal workup a f f o r d e d a y e l l o w o i l , w h i c h was p u r i f i e d by p r e p a r a t i v e t i c on 12% (w/w) s i l v e r n i t r a t e -s i l i c a g e l ( d e v e l o p i n g s o l v e n t : p e t r o l e u m e t h e r - e t h e r , 5:1). D i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 130-142°C, 20 t o r r ) o f the m a t e r i a l thus o b t a i n e d gave 28 mg (69%) o f 195. A g l c a n a l y s i s (column A) showed the p r e s e n c e o f one component. T h i s m a t e r i a l e x h i b i t e d i r ( f i l m ) : 3080, 3050, 1651, 1603, 990, 900 cm" 1; 1U nmr (CDC1 3) 6: 1.15-1.68 (m, 3H), 1.75 (d, 3H, v i n y l m e t h y l , J^1.5Hz), 1.88-2.47 (m, 5H), 2.47-2.85 (m, IH, t e r t i a r y p r o t o n ) , 4.96 (d o f d, IH, H a, J a b = 2 H z , J a c = 1 0 H z ) , 5.07 (d o f d, IH, H f a, J a b = 2 H z , J b c = 1 6 . 5 H z ) , 5.68 (m, 2H, c y c l o p e n t e n y l o l e f i n i c p r o t o n s ) , 5.86 (d o f d, IH, H d, J c d = l l H z , J'^1.5Hz). E x a c t mass c a l c d . f o r C 1 2 H 1 8 : 162.1409; found: 162.1406. P r e p a r a t i o n o f ( E ) - 6 - ( 2 - C y c l o p e n t e n y l ) - 4 - m e t h y 1 - 1 , 3 -h e x a d i e n - 5 - o l 196 - 200 -F o l l o w i n g t h e g e n e r a l p r o c e d u r e M o u t l i n e d above, 0.25 mmol o f ( Z ) - 4 - l i t h i o - l , 3 - p e n t a d i e n e 186 was a l l o w e d t o r e a c t w i t h ( 2 - c y c l o p e n t e n y l ) e t h a n a l (36 mg, 0.33 mmol) i n t e t r a -h y d r o f u r a n a t -78°C f o r l h . Normal workup, f o l l o w e d by d i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 79-85°C, 0.2 t o r r ) o f the cru d e m a t e r i a l a f f o r d e d 36 mg (82%) o f t h e die'ne 196 as a c o l o r l e s s o i l . T i c and g l c a n a l y s e s ( s i l i c a g e l and column A, r e s p e c t i v e l y ) showed the pr e s e n c e o f one component. T h i s m a t e r i a l e x h i b i t e d i r ( f i l m ) : 3345, 3070, 3040, 1643, 1598, 900 cm" 1; 1 H nmr (CDC1 3) <5 : 1.15-1.83 (m, 4H), 1.78 (d, 3H, v i n y l m e t h y l , J^1.5Hz), 1.83-2.48 (m, 3H, 2.48-2.93 (m, IH, t e r t i a r y p r o t o n ) , 4.14 (broad t , IH, -CHOH, J=7Hz), 5.09 (d o f d, IH, H , J ,=2Hz, J =10Hz), 5.19 (d o f d, IH, H b, J a b = 2 H z , J b c = 1 6 . 5 H z ) , 5.71 (m, 2H, c y c l o p e n t e n y l o l e f i n i c p r o t o n s ) , 6.04 (broad d, IH, H^, J , = H H z ) , 6.59 (m, IH, H , J =10Hz, J, =16.5Hz, J ,=HHz) . cd c ac be cd E x a c t mass c a l c d . f o r C 1 2 H 1 8 0 : 1 7 8 - 1 3 5 7 ' ' found: 178.1360. P r e p a r a t i o n o f ( E ) - 4 - ( 1 - H y d r o x y c y c l o p e n t y l ) - 1 , 3 - p e n t a d i e n e 197 - 201 -F o l l o w i n g the g e n e r a l p r o c e d u r e M o u t l i n e d above, 0.25 mmol o f (Z)-4-lithio-l,3-pentadiene 18 6 was a l l o w e d t o r e a c t w i t h c y c l o p e n t a n o n e (27 mg, 0.33 mmol) i n t e t r a h y d r o -f u r a n a t -78°C f o r l h . Normal workup, f o l l o w e d by d i s t i l l -a t i o n ( a i r - b a t h t e m p e r a t u r e 60-75°C, 0.2 t o r r ) o f t h e crud e m a t e r i a l a f f o r d e d 28 mg (74%) o f the d i e n e 197. T i c and g l c a n a l y s e s ( s i l i c a g e l and column A, r e s p e c t i v e l y ) showed the p r e s e n c e o f one major component. T h i s m a t e r i a l e x h i b i t e d i r ( f i l m ) : 3370, 3075, 3040, 1640, 1597, 985, and >2 902 cm 1 ; 1 H nmr (CDC1 3) 5: 1.30 ( s , IH, exchanged w i t h D„0, -OH), 1.55-2.00 (broad u n r e s o l v e d s i g n a l , 8H, c y c l o p e n t y l m e t h y l e n e s ) , 1.83 (d, 3H, v i n y l m e t h y l , J^1.5Hz), 5.09 (d o f d, IH, H , J ,=2Hz, J =10Hz), 5.18 (d o f d, IH, H b ' J a b = 2 H z ' J b c = 2 H z ^ ' 6 , 1 8 ^ d ° f d ' 1 H ' H d ' J c d = l l H z ' J'^1.5Hz), 6.59 (m, IH, H , J =10Hz, J, =16Hz, J ,=llHz) c ac ' b e cd E x a c t mass c a l c d . f o r c 1 0 H 1 6 O : 1 5 2 - 1 2 0 1 ' * found: 152.1201. P r e p a r a t i o n o f ( Z ) - 4 - M e t h y l - l , 3 - d o d e c a d i e n e 198 198 F o l l o w i n g the g e n e r a l p r o c e d u r e M o u t l i n e d above, 0.25 mmol o f ( E ) - 4 - l i t h i o - l , 3 - p e n t a d i e n e 187 was a l l o w e d t o - 202 -r e a c t w i t h 1-bromooctane (64 mg, 0.33 mmol) i n t e t r a h y d r o -f u r a n a t -78°C f o r l h . Normal workup a f f o r d e d a y e l l o w o i l , w h i c h was p u r i f i e d by p r e p a r a t i v e t i c on 12% (w/w) s i l v e r n i t r a t e - s i l i c a g e l ( d e v e l o p i n g s o l v e n t : p e t r o l e u m e t h e r - e t h e r , 98:2). D i s t i l l a t i o n ( a i r - b a t h t e m p e r a t u r e 143-149°C, 20 t o r r ) o f the o i l thus o b t a i n e d a f f o r d e d 28 mg (62%) o f the d i e n e 198. A g l c a n a l y s i s (column A) showed the p r e s e n c e of one component. T h i s m a t e r i a l e x h i b i t e d i r ( f i l m ) : 3090, 3040, 1653, 1601, 995, 903 cm" 1; 1H nmr (CDC1 3) 6: 0.75-1.02 (m, 3H, t e r m i n a l m e t h y l ) , 1.13-1.55 (broad u n r e s o l v e d s i g n a l , 12H, n o n - a l l y l i c m e t h y l e n e s ) , 1.78 (bs, 3H, v i n y l m e t h y l ) , 2.04-2.33 (m, 2H, a l l y l i c m e t h y l e n e ) , 4.96 (d o f d, IH, H , J ,^2Hz, J =10Hz), 3. cit) dC 5.08 (d o f d, IH, R , J a b ^ 2 H z , J b m = 1 6 H z ) , 5.86 (bd, IH, H d ' J c d = l l H z ) ' 6 , 4 1 ( m ' 1 H ' H c ' J a c = 1 0 H z ' J b c = 1 6 H z ' J -, = l l H z ) . E x a c t mass c a l c d . f o r C,_H 0.: 180.1878; cu 13 24 found: 180.1890. P r e p a r a t i o n o f {Z)-6-(2-Cyclopentenyl)-4-methyl-l,3-h e x a d i e n - 5 - o l 199 199 - 203 -F o l l o w i n g the g e n e r a l p r o c e d u r e M o u t l i n e d above, 0.25 mmol o f ( E ) - 4 - l i t h i o - l , 3 - p e n t a d i e n e 187 was a l l o w e d t o r e a c t w i t h ( 2 - c y c l o p e n t e n y l ) e t h a n a l (36 mg, 0.33 mmol) i n t e t r a h y d r o f u r a n a t -78°C f o r l h . Normal workup, f o l l o w e d by d i s t i l l a t i o n o f the cr u d e o i l a f f o r d e d 34 mg (76%) o f 199. T i c and g l c a n a l y s e s ( s i l i c a g e l and column A, r e s p e c t i v e l y ) showed the p r e s e n c e o f one component. T h i s m a t e r i a l e x h i b i t e d i r ( f i l m ) : 3360, 3075, 3045, 1640, 1595, 900 cm" 1; 1 H nmr (CDCl-j) 6: 1.18-1.74 (m, 4H) , 1.84-2.46 (m, 3H) , 2.48-2.94 (m, IH, t e r t i a r y p r o t o n ) , 4.81 ( t , IH, -CHOH, J=7Hz), 5.08 (broad d, IH, H , J ,^2Hz, J =10Hz), — cl 3.1D c l C 5.16 (broad d, IH, H f a / J a b ^ 2 H z , J b c = 1 6 . 5 H z ) , 5.76 (m, 2H, c y c l o p e n t e n y l o l e f i n i c p r o t o n s ) , 5.86 (broad d, IH, , J c d = 1 2 H z ) , 6.70 (m, IH, H c , J a c = 1 0 H z , J b c=16.5Hz, J c d = 1 2 H z ) . E x a c t mass c a l c d . f o r C 1 o H l o 0 : 178.1357; found 178.1366. - 204 -BIBLIOGRAPHY For a r e v i e w on methods o f r e a c t i v i t y umpolung, see D. A. Evans and G. C. Andrews. A c c . Chem. Res. 7_, 147 (1974); D. Seebach. Angew: Chem. I n t . Ed. E n g l . 18, 239 (1979) . E. P i e r s and I . Nagakura. Synth. Commun. 5_, 193 (1975); C. K. Lau. Ph.D. t h e s i s , U n i v e r s i t y o f B r i t i s h C o l u m b i a , Canada, 1978. (a) E. P i e r s and I . Nagakura. J . Org. Chem. 40, 2694 (1975) (b) E. P i e r s , C. K. Lau, and I . Nagakura. T e t r a h e d r o n  L e t t . 3233 (1976); (c) E. P i e r s and I . Nagakura. i b i d . 3237 (1976); (d) E. P i e r s and C. K. Lau. Syn t h . Commun. 7, 495 (1977); (e) E. P i e r s , I . Nagakura, and J . E. Shaw. J . Org. Chem. 43 , 3431 (1978); (f ) E. P i e r s , I . Nagakura, and H.E. Morton i b i d . 43, 3630 (1978); (g) E. P i e r s and E. R u e d i g e r . J . Chem. Soc. Chem. Commun. 166 (1979). F o r r e l a t e d i n d e p e n d e n t l y p u b l i s h e d r e s u l t s , ' see E. E. van Tamelen, M. P. S e i l e r , and W. Wierenga. J . Am. Chem. Soc. 94 , 8229 (1972); J . L. Hermann, J . E. Richman, and R. H. S c h l e s s i n g e r . T e t r a h e d r o n L e t t . 2599 (1973); J . P. Marino and T. Kaneko. i b i d 3971, 3975 (1973); R. D. C l a r k and C. H. Heathcock. J . Org. Chem. 39, - 205 " 3658 (1973); Y. Taraura, T. Miyamoto, T. N i s h i m u r a , J . E i h o , and Y. K i t a . J . Chem. Soc. P e r k i n I 102 (1974); R. D. C l a r k and C. H. Heathcock. i b i d . 41, 636 (1976) . E. J . Corey and D. J . Beams. J . Am. Chem. Soc. 94, 7210 (1972) . Fo r r e c e n t r e p o r t s c o n c e r n i n g the t r a n s m e t a l a t i o n o f t r i a l k y l v i n y l s t a n n a n e s , and r e f e r e n c e s c i t e d t h e r e i n , see ( a ) . R. H. W o l l e n b e r g , T e t r a h e d r o n L e t t . 717 (1918); (b) S. L. Chen, R. E. Schaub, and C. V. G r u d z i n s k a s . J . Org. Chem. 43, 3450 (1978); (c) P.W. C o l l i n s , C. J . Jung, A. G a s i e c k i , and R. Pappo. T e t r a h e d r o n L e t t . 3187 (1978). E. J . Corey and R. N o y o r i . T e t r a h e d r o n L e t t . 311 (1970); E. J . Corey, B. W. E r i c k s o n , and R. N o y o r i J . Am. Chem. Soc. 93, 1724 (1971); R. G. C a r l s o n and W. S. M a r d i s . J . Org. Chem. 40, 818 (1975); K. Oshima, H. Yamamoto, H. M o z a k i . B u l l . Chem. Soc. Japan 48, 817 (1975); R. R. Schmidt and J . T a l b i e r s k y . Angew. Chem., I n t . Ed. Eng.15, 171 (1976); T. Cohen, D. A. B e n n e t t , and A. J . Mura, J r . , J . Org. Chem. 41, 2506 (1976); M. Wada, H. Nakamura, T. Taguchi and H. Takae. Chem. L e t t . 34 5 (1977); R. R. Schmidt and J . T a l b i e r s k y . Angew. Chem., I n t . Ed. Eng. 16, 854 (1977); R. R. Schmidt, J . T a l b i e r s k y , and P. Russegger. T e t r a h e d r o n L e t t . 4273 (1979); I . Kuwajina and M. K a t o . T e t r a h e d r o n L e t t . 623 (1980). K. Kondo and D. Tunenoto. T e t r a h e d r o n L e t t . 1007, 1397 (197 5 ) ; K. Kondo, E. S a i t o , and D. Tunenoto. i b i d . 2275 (1975). For some r e l a t e d examples see M. J u l i a and B. Badet. B u l l . Soc. Chim. F r a n c e 1363 (1975); K. I w a i , H. K o s u g i , A. M i y a y a k i , and H. Uda. Sy n t h . Commun. 6_, 357 (1976); G. K. Cooper and L. J . Dolby. T e t r a h e d r o n L e t t . 4 67 5 (1976); J . Fayos and J . C l a r d y . J . Org. Chem. 42, 1349 (1977). P. B a k u j i s , M.L.F. B a k u j i s , and T. F. W e i n g a r t n e r . T e t r a h e d r o n L e t t . 2371 (1978) . D. Seebach, M. S. H o e k s t r a , and G. P r o t s c h u k . Angew. Chem., I n t . Ed. E n g l . 16, 321 (1977). A. D e b a l , T. C u v i g n y , and M. Larcheveque. T e t r a h e d r o n  L e t t . 3187 (1977) . P. C. Conrad and P. L. Fuchs. J . Am. Chem. Soc. 100, 346 (1978). J . C. S a d d l e r , P. C. Conrad, and P. F. Fuchs. T e t r a h e d r o n L e t t . 5079 (1978) . D. C a i n e and A. S. F r o b e s e . T e t r a h e d r o n L e t t . 5169 (1978) W. R. Baker and R. M. C o a t e s . J . Org. Chem. 44, 1022 (1978). M. L. Hammond, A. Mourino, and W. H. Okamura. J . Am. Chem. Soc. 100, 4907 (1978) . P. Condran, J r . , M. L. Hammond, A. Mourino, and W. H. Okamura. J . Am. Chem. Soc. 102, 6259 (1980) - 207 -19. A. Mourino, S. L e w i c k a - P i e k u t , A. W. Norman, and W. H. Okamura. J . Org. Chem. 45, 4015 (1980) . 20. C. J . S i h , P. P r i c e , R. Sood, R. G. Salamon, G. P e r u z z o t t i , and M. Casey. J . Am. Chem. Soc. 94, 3643 (1972); r e f . 5; A. F. K l u g e , K. G. Untch, and J . H. F r i e d . J . Am. Chem. Soc. 94, 7827 (1972); C. J . S i h , R. G. Salamon, P. P r i c e , R. Sood, and G. P e r u z z o t t i . i b i d . 97, 857 (1975); G. W. S t o r k and M. I s o b e . i b i d . 97, 6260 (1975); K. F. Bernady, J . F. P o l e t t s , and M. J . Weiss. T e t r a h e d r o n L e t t . 765 (1975); R. T. B u c k l e r and D. L. G a r l i n g . i b i d . 2257 (1978); R. N o y o r i , I . Tomino, and M. N i s h i y a w a . J . Am. Chem. Soc. 101, 5843 (1979) . 21. E. J . Corey and A. V e n k a t e s w a r l u . J . Am. Chem. Soc. 9_4, 6190 (1972) . 22. T. Mukaiyama. Angew Chem., I n t . Ed. E n g l . 16, 817 (1977); E. W. C o l v i n . Chem. Soc. Rev. 7, 15 (1978). 23. J . A. K a t z e n e l l e n b o g e n and K. J . C h r i s t y . J . Org. Chem. 3_9, 3315 (1974) . 24. W. C. S t i l l . J . Am. Chem. Soc. 99, 4836 (1977). 25. W. C. S t i l l and A. M i t r a . T e t r a h e d r o n L e t t . 2659 (1978). 26. W. P. Neumann, "The O r g a n i c C h e m i s t r y o f T i n " , J . W i l e y and Sons, London, 1970, p. 215. 27. Ref. 26, page 220. 28. G. H. Po s n e r , Org. Re a c t . 19, 1 (1972). 29. J . F. Normont. S y n t h e s i s 63 (1972). - 208 -J . F. Normont. J . Organometal. Chem. L i b , 1, 219 (1975) . G. H. P o s n e r , D. J . B r u n e l l e , and L. Sinoway. S y n t h e s i s 622 (1974). J . E. Dubois and M. Du b o i s . Acad, des S c i e n c e s 256, 715 (1963) . " S a d t l e r NMR S p e c t r a " , S a d t i e r Research L a b o r a t o r i e s I n c . , P h i l a d e l p h i a , 1975, #20292. A. J . L e u s i n k , H. A. Budding, and J . W. Marsmann. J . Organometal. Chem. 9, 285 (1967). H. P. House, C. Y. Chu, J . M. W i l k i n s , and M. J . Umen. J . Org. Chem. 40, 1460 (1975). J . Hudec. J . Chem. S o c , P e r k i n Trans. 1, 1020 (1975). A. I . S c o t t , " I n t e r p r e t a t i o n o f the U l t r a v i o l e t S p e c t r a o f N a t u r a l P r o d u c t s " , Pergamon P r e s s , N.Y., 1964. R. B. Woodward. J . Am. Chem. Soc. 64, 72 (1942). L. F. F i e s e r and M. F i e s e r . " S t e r i o d s " , R e i n h o l d , N.Y., 1959, p. 15-24. W. F. Gannon and H. 0. House. Org. Syn. 40, 14, (1960). E. W. Warnhoff, D. G. M a r t i n , and W. S. Johnson. Org. Syn. C o l l . V o l . 4, 162 (1963). W. M. S c h u b e r t and W. A. Sweeney. J . Am. Chem. Soc. 77, 2297 (1955). H. N. A. A l - J a l l o and E. S. Waight. J . Chem. Soc. ( B ) , 73 (1966). - 209 -44. R. L. E r s k i n and E. S. Waight J . Chem. Soc. 3425 (1960). 45. Ref. 26, p. 230. 46. (a) H. O. House, L. J . Czuba, M. G a l l , and H. D. Olmstead. J . Org. Chem. 34, 2324 (1969); (b) C. G i r a r d and J . M. C o n i a . T e t r a h e d r o n L e t t . 3327 (1974); (c) G. M. Rubottom and J . M. Gruber. J . Org. Chem. 42, 1051 (1977) . 47. J . M. R e u t e r , A. S i n h a , and G. R. Salomon. J . Org. Chem. 43, 2438 (1978) . 48. J . S c h r e i b e r , H. Maag, N. Hashimoto, and E. Eschenmoser. Angew. Chem., I n t . Ed. Eng. 10, 330 (1971). 49. G. F. Woods, P. H. Grenswold, J r . , B. H. Ar m b r e c k t , D. I . B l u m e n t h a l , and R. P l a p i n g e r . J . Am. Chem. Soc. 71, 2028 (1949) . 50. W. C. S t i l l . J . Am. Chem. Soc. 101, 2493 (1979). 51. J . C. C o l l i n s , W. W. Hess, and F. J . Fr a n k . T e t r a h e d r o n  L e t t . 3363 (1968). 52. G. H. Po s n e r , C. E. W h i t t e n , and J . J . S t e r l i n g . J . Am. Chem. Soc. 9J5, 7788 (1973) . 53. M. S u z u k i , T. S u z u k i , T. K a w a g i s h i , and R. N o y o r i . T e t r a h e d r o n L e t t . 1247 (1980) . 54. J . C. Lahournere and J . V a l a d e . J . Organometal. Chem. 33, C-7 (1971) . - 210 ~ 55. H. G. K u i v i l a , J . E. Dixon> P. L. M a x f i e l d , N. M. S c a r p a , T. M. Topka, K. T s a i , and K. R. Wursthorn. J . Organometal, Chem. 86, 89 (1975) . 56. A. J. L e u s i n k , J . W. Marsman, H. A. Budding, J . G. N o l t e s , and G. J . M. Van der Kerk. Rec. Trav. Chim. 84, 567 (1965); see a l s o r e f . 34. 57. F o r a r e l a t e d example i n v o l v i n g the a d d i t i o n o f t r i m e t h y l s t a n n y l s o d i u m t o a , g - u n s a t u r a t e d ketones and e s t e r s i n the pre s e n c e o f e t h a n o l see, H. G. K u i v i l a and G. H. L e i n , J r . , J . Org. Chem. 43, 750 (1978). 58. E. J . Corey and J . A. K a t z e n e l l e n b o g e n . J . Am. Chem. Soc. 91, 1851 (1969) . 59. J . B. S i d d a l l , M. B i s k u p , and J . H. F r i e d . J . Am. Chem. Soc. 91, 1853 (1969). 60. H. G. K u i v i l a , K. T s a i , and D. G. I . K i n g s t o n . J . Organometal. Chem. 23, 129 (1970). 61. R. S. D a v i d s o n , W. H. H. Gunther, S. M. Waddington-Feather, and B. Lythgoe. J . Chem. Soc. 4907 (1964). 62. I . F l e m i n g and D. H. W i l l i a m s , " S p e c t r o s c o p i c Methods i n Or g a n i c C h e m i s t r y " , M c G r a w - H i l l , London, 2nd ed., 1973, p. 140. 63. A. J . L e u s i n k . Ph.D. t h e s i s , S t a t e U n i v e r s i t y of U t r e c h t , The N e t h e r l a n d s , 1966; see a l s o r e f . 56. 64. A. J . L e u s i n k , J . W. Marsman and H. A. Budding. Rec. Trav. Chim. 84, 689 (1965) . - 211 -65. B. F o h l i s c h and W. G i e r i n g . S y n t h e s i s 231 (1980). 66. A. T. N i e l s e n . J . Org. Chem. 22, 1539 (1957) 67. H. H. J a f f e and M. O r c h i n , "Theory and A p p l i c a t i o n s o f U l t r a v i o l e t S p e c t r o s c o p y " , J . W i l e y and Sons, New Yor k , N.Y., 1962. 68. W. D. C l o s s o n , S. F. Brady, E. H. Kosower, and P. C. Huang. J . Org. Chem. 28, 1161 (1963). 69. J . L. H. A l l a n , E. R. H. Jones and M. C. W h i t i n g . J . Chem. Soc. 1862 (1955). 70. S. R. Landor and N. P u n j a . J . Chem. Soc. C 2495 (1967). 71. K. E. W i l s o n , R. T. S e i d n e r , and S. Masamune. J . Chem. S o c , Chem. Commun. 213 (1970) . 72. H. F i r o u z a b a d i and E. G h a d e r i . T e t r a h e d r o n L e t t . 839 (1978). 73. G. W i t t i g and U. S c h o e l l k o p f . Org. Syn. 40, 66 (1960). 74. Ref. 62, p. 145. 75. H. Gilman and F. K. C a r t l e d g e . J . Organometal. Chem. 2_, 447 (1964) . 76. A. J . Gordon and R. A. F o r d , "The Chemist's Companion: A Handbook o f P r a c t i c a l Data, Techniques and R e f e r e n c e s " , J . W i l e y and Sons, N.Y., 1972, p. 439. 77. L. Horner, H. O e d i g e r , and H. Hoffmann. Ann a l e n d e r  Chemie 626, 26 (1959); G. A. W i l e y , R. L. H e r s h k o w i t z , B. M. R e i n , and B. C. Chung. J . Am. Chem. Soc. 86, 964 (1964). 78. D. L. G a r i n . J . Org. Chem. 34, 2355 (1969). - 212 -79. R. K. H i l l and A. G. Edwards. T e t r a h e d r o n L e t t . 3239 (1964). 80. A. J . L e u s i n k and J . G. N o l t e s . J . Organometal Chem. 16, 91 (1969). 81. M. G. Dupont. Compt. r e n d . 148, 1522 (1909). 82. " B e i l s t e i n s Handbuch der O r g a n i s c h e n Chemie", J u l i u s S p r i n g e r , B e r l i n , 1920, Bund I I , S y s t . No. 164. 83. C. Moureu and R. Delange. Compt. r e n d . 136, 552 (1903). 

Cite

Citation Scheme:

        

Citations by CSL (citeproc-js)

Usage Statistics

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
http://iiif.library.ubc.ca/presentation/dsp.831.1-0060744/manifest

Comment

Related Items