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Synthesis of 1,1-disubstituted alkyl vinyl sulfides via rhodium-catalyzed alkyne hydrothiolation : scope… Yang, Jun 2008

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SYNTHESIS OF 1,1-DISUBSTITUTED ALKYL VINYL SULFIDES VIA RHODIUM-CATALYZED ALKYNE HYDROTHIOLATION: SCOPE AND LIMITATIONS by JUN YANG B.Sc., Fudan University, 2006 A THESIS SUBMITTED iN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in THE FACULTY OF GRADUATE STUDIES (Chemistry) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) September 2008 © Jun Yang, 2008 Abstract Tp*Rh(PPh3)2is a useful catalyst for alkyne hydrothiolation. Vinyl sulfides, the products of this reaction, are useful synthetic intermediates. The goal of this thesis project was to explore the scope and limitations of alkyne hydrothiolation with alkyl thiols catalyzed by Tp*Rh(PPh3)2.A variety of thiols and alkynes successfully undergo catalytic hydrothiolation. In general, the branched isomer was formed in good-to-excellent yields and with high selectivity. Electron rich phenylacetylenes were more reactive than electron deficient ones, and provided higher yields. Aliphatic alkynes need longer reaction times than aromatic alkynes in order to reach complete conversion. A broad range of functional groups were well tolerated, including halides, amines, nitriles, amines, ethers, esters and silanes. Alkoxy groups with the ability to coordinate with rhodium slowed down the catalytic turnover and lowered the yields. Strongly coordinating groups, such as pyridine, precluded catalysis. Alkynes that are Michael acceptors react with reversed regioselectivity. Hydrothiolation using internal alkynes was successful, although the reaction times were longer and temperatures are higher than that needed for terminal alkynes. Overall, the work presented in this thesis provides a general method in construction of branched alkyl vinyl sulfides from alkynes. 11 Table of Contents Abstract Table of Contents.lii List of Tables v List of Figures vi List of Schemes vii List of Symbols and Abbreviations vffl Acknowledgements x Chapter 1 — Introduction 1 1.1 Background 1 1.2 Hydrothiolation Reactions 3 1.2.1 Linear Isomers 3 1.2.1.1 Free Radical Hydrothiolation 4 1.2.1.2 Nucleophilic Hydrothiolation 4 1.2.1.3 Transition Metal-Catalyzed Hydrothiolation 6 1.2.2 Branched Isomer 8 1.2.2.1 Nucleophilic Hydrothiolation 8 1.2.2.2 Transition Metal-Catalyzed Hydrothiolation 9 1.3 Previous work of our group 13 1.4 Conclusions 16 Chapter 2 —Substrates Scope and Limitations of Tp*Rh(PPh3)2Catalyzing Alkyne Hydrothiolation 17 2.1 Introduction 17 2.2 Results and Discussion 18 2.2.1 Hydrothiolation of Benzylthiol and Aryl Alkynes 18 2.2.2 Hydrothiolation of Benzylthiol and Aliphatic Alkynes 21 2.2.3 Hydrothiolation of Phenylacetylene with Different Thiols 24 2.2.4 Hydrothiolation of Different Alkynes and n-Propanethiol 26 2.2.5 Hydrothiolation of Internal Alkynes and Other Cases 26 111 2.3 Experimental Procedures .28 2.3.1 General Methods 28 2.3.2 Materials and Methods 28 2.3.3 General experimental procedure for hydrothiolation 29 Chapter 3— Summary and Future Work 69 4.1 Summary 69 4.2 Future Work 70 References 72 Appendices X-ray Crystallographic Data for Complex II 77 iv List of Tables Table 2.1. Scope of Hydrothiolation of Aryl Alkynes with Benzylthiol Catalyzed by I. 19 Table 2.2. Scope of Hydrothiolation of Aliphatic Alkynes with Benzylthiol Catalyzed by I 22 Table 2.3. Scope of Hydrothiolation of Phenylacetylene with Different Thiols Catalyzed by I 25 Table 2.4. Scope of Hydrothiolation of Internal Alkynes Catalyzed by! 27 V List of Figures Figure 1.1. Griseoviridin 1 Figure 1.2. Tp*Rh(PPh3) 13 Figure 2.1. ORTEP diagram of complex II 21 Figure 3.1. Emtricitabine, Eletriptan, and Ertapenem 70 vi List of Schemes Scheme1.1.4 Scheme 1.2 7 Scheme 1.3 8 Scheme 1.4 9 Scheme 1.5 10 Scheme 1.6 11 Scheme 1.7 11 Scheme 1.8 12 Scheme 1.9 14 vii List of Symbols and Abbreviations A angstroms (10’° meters) mu, micro br broad calcd calculated cat. catalyst cm centimeters J coupling constant o degrees °C degrees Celcius d deuterium DCE 1 ,2-dichloroethane Bp dihydrobisQ,yrazolyl)borate d doublet El electron impact equiv. equivalents Et ethyl v frequency gamma GC-MS gas chromatography-mass spectroscopy g gram Hz hertz HRMS high resolution mass spectroscopy h hours Tp hydrotris(pyrazolyl)borate i iso i-Pr isopropyl K kappa K kelvin kcal kilocalorie L liter LRMS low resolution mass spectroscopy m!z mass/charge MALDI matrix-assisted laser desorptionlionization MHz mega hertz Me methyl DCM dichioromethane tL microliter mg milligram viii mL milliliter mmol millimole mm minutes M molar (mol L’) mol mole m multiplet n noimal NMR nuclear magnetic resonance ORTEP Oakridge Thermal Ellipsoid Plot ppm parts per million Ph phenyl pi q quartet rt room temperature SEM scanning electron microscopy S singlet t tertiary t triplet THF tetrahydrofuran TEMPO 2,2,6,6-tetramethylpiperidine-N-oxyl PMe3 trimethyiphosphine PPh3 triphenyiphosphine UV ultra violet Z zusammen E entgegen DBU 1 ,8-Diazabicyclo[5.4.O]undec-7-ene Tp* tris(3 ,5-dimethylpyrazolyl)borate tris(3 -phenyl,5-methylpyrazolyl)borate ix Acknowledgements Two years ago, it was my first time to set my first step on this beautiful land. Two years later, I finished my research and thesis under supervision of Dr. Jennifer A. Love. I would like to thank Dr. Love for her support, direction over the course of the project. Her enthusiasm, motivation and knowledge inspire me a lot in my graduate studies and researches. Her patience and advice help me stride over many difficulties. I would also thank all my group members, Paul Bichier, Heather Buckley, Alex Dauth, Lauren Fraser, Anthony Sabarre, Shiva Shoai, Duo Sun, Sara van Rooy and Tongen Wang for all of their help and support during the two years. I would like to give special thank to Lauren Fraser, Anthony Sabarre, and Shiva Shoai for their teaching, discussing and advising on my research, and to Paul Bichier, Alex Dauth, Duo Sun, and Tongen Wang for proofreading my thesis. Thanks also go to the NMR staff (Nick Burlinson, Zorana Danilovic, Maria Ezhova and Zhicheng Xia), the mass spectroscopy and elemental analysis staff (especially David Wang) and the stores staff. I really appreciate Brian Patrick for the X-ray crystal structures. I would like to acknowledge all my friends outside the lab, Xu Li, Ying Li, Yi Cao, Yuan Zhou, Ran Zhang and Xuefei Zhong. It is really a nice time to play cards and games with you guys. I also give my thanks to my parents, Guangming Yang and Mingxia Zhang, and my grandmother, Xiuzhu Yu. I will not be where I am today without their love and support. I also hope my grandfather Guangyang Zhang can get the news that I have finished my master’s study in the heaven. For my significant other, Xingzhi Yu, thank you very much for your support and positive motivation even when I was upset. x Chapter 1— Introduction 1.1 Background Sulfur is a very important element in nature. It is used in many industrial products such as rubber, detergents, fungicides, dyestuffs, agrichemicals, and medicines.’ Many natural products also contain C-S bonds. Griseoviridin, a broad spectrum streptogramin antibiotic, is only one of many examples.2 OHOH Figure 1.1. Griseoviridin Vinyl sulfides are important synthetic intermediates and powerful building blocks for many natural and synthetic molecules.3Cross coupling of vinyl halides and thiols is a viable method to obtain vinyl sulfides.4However, alkyne hydrothiolation, the addition of a thiol to the it-bond of an acetylene, is a more atom-economical method to gain vinyl sulfide products, by converting all of the atoms in the starting materials into the products, thereby limiting waste production. Generally, in alkyne hydrothiolation of terminal alkynes, there are three potential products: branched, E-linear, and Z-linear isomers (eq 1.1). Free radical5 and nucleophilic6 hydrothiolation have been applied for making vinyl sulfides, but these 1 methodologies are generally limited to aryl thiols. Another significant disadvantage is that neither method can give branched products: free radical reactions only give the linear isomer without selectivity and nucleophilic reactions preferentially generate the Z-linear isomer. RSH + R1 R1c + RlSR + R1 (1.1) branched E-linear Z-Iinear Transition metal catalyzed cross coupling reactions are widely used in the construction of carbon-heteroatom bonds. The use of amines,7 alcohols8 and phosphines9 in cross coupling reactions with suitable substrates is well documented in the literature. However, because of the widespread prejudice that thiols are considered as catalyst poisons,’° the transition metal catalyzed addition of thiols to alkynes has not received as much attention. Moreover, the cases of synthesizing branched alkyl vinyl sulfides using transition metal are even scarce. Therefore, there is a great demand to find a general synthetic method towards the branched alkyl vinyl sulfides selectively. 2 1.2 Hydrothiolation Reactions As shown before, there are three major products in the hydrothiolation of alkynes. The branched isomer is formed from Markovnikov addition, whereas the E-linear and Z linear isomers are formed from anti-Markovnikov addition. Comparing the two linear products, the Z-linear isomer is kinetically favored while the E-linear isomer is thermodynamically more stable. In this section, the methods to form the linear and branched isomers will be discussed in detail. 1.2.1 Linear Isomers The first publication in this field was by H. Bader and co-workers in 1949.” In this paper, 1 -hexyne was treated with thioacetic acid and was heated for 10 mm to give 1- hexenyl thioacetate in 53% yield (eq 1.2). The mechanism and stereoselectivity of this reaction were not mentioned. __ heat n-C4H9 SCOCH3 CH3OSH + n-C4H9 (1.2) H H 53% Isomerization between E- and Z-linear adducts often accompanies the reaction (eq 1.3). Based on Truce and co-workers’ publication in 1972, the equilibrium could be achieved in 15 mm under dilute acidic conditions, while under basic condition it needed hours or days.6’ The ratio of the E- and Z-linear isomers was approximately 3:1 . conditionsR 1 RSR (1.3) SR Z-Iinear E-Iinear 3 1.2.1.1 Free Radical Hydrothiolation Free radical reactions were versatile in the synthesis of organic molecules, and free radical hydrothiolation has been under investigation since the 1960s. Usually this type of reaction was induced by either UV radiation or chemical initiators.5”However, the ratio of the E- and Z-linear isomers was often hard to controL5’Generally, the Z-linear isomer was formed preferentially. In some cases, the ratio of the products depended on the ratio of thiol to alkyne. For example, in the free radical addition of benzenethiol to phenylacetylene, when the ratio of thiol to alkyne was 20:1, the Z-linear isomer was formed in 16% yield. When the ratio was changed to 1:1, the yield of the Z-linear isomer was 56%. In comparison, when the ratio was 1:20, the Z-linear isomer was formed in over 95% yield.5a In 1987, Oshima and co-workers reported the free radical hydrothiolation reaction catalyzed by Et3B. The yields for aromatic thiol were good-to-excellent (70-91%), but for aliphatic thiols, the yields were low even after prolonged reaction time. This problem can be solved by adding 4 equivalents of methanol. However, this reaction showed no stereoselectivity between the E and Z-linear isomers (see Scheme 1.1 )•5(1 ___ Et3B n-C10H21 SPh n-C10H21 SPh PhSH + n-C10H21 — =.( H H H Scheme 1.1 1.2.1.2 Nucleophiic Hydrothiolation Nnucleophilic hydrothiolation favored the Z-linear product via trans-addition of thiol to a1kyne6 In the early stage of nucleophilic hydrothiolation, thiols were 4 deprotonated to the thiolate first and then reacted with acetylenes in ethanol to produce Z linear isomers in moderate to good yields(65..87%)6a The reaction between p toluenethiolate and acetylenes containing carbonyl groups, such as amide and acetyl, gave high degree of Z-adducts, but also had some E-adducts (about 10-20%). However the other activating groups such as p-tolysulfonyl, cyano, and p-nitrophenyl gave the Z adducts exclusively (eq 1.4).6c R— + __e R + RSrl (1.4) Z-Iinear E-Iinear H3CO2-[ 92% 8% H2NOC- 87% 13% H3COC- 82% 18% NEC-- 100% 0% 100% 0% 100% 0% In 2005, Oshima and co-workers reported stereoselective hydrothiolation catalyzed by cesium carbonate. Aryl alkynes and alkyl thiols were used in this reaction and the Z linear isomer was found to be preferred.6 A free radical pathway was completely inhibited by the radical inhibitor (TEMPO), so only nucleophilic hydrothiolation occurred. The electronic effect of the arylacetylenes had been examined: electron donating groups gave the Z-isomer exclusively but higher temperature was needed in order to get high yields; the electron withdrawing groups could help the reaction occur even at room temperature but without selectivity, and E-linear isomer was favored at high 5 reaction temperature. A limitation of this methodology was that aryl thiols were found to give poor yield even at high temperature. 1.2.1.3 Transition Metal-Catalyzed Hydrothiolation In 1976, Newton and co-workers discovered the first hydrothiolation reaction, catalyzed by molybdenum. Thiols were treated as both the electron and proton donor in the reaction. 12a The molybdenum catalyst facilitated the reaction between benzenethiol and dimethyl acetylenedicarboxylate in 25% yield with over 95% of the E-isomer (eq 1.5). SPh __ MoO [S C(1- )] SPhMeO2C CO2Me 16 2 MeO2C MeO2CC02Me (1.5) PhSH >95% <5% The methodology for selectively synthesizing the E-linear isomer was greatly improved by Ogawa and co-workers in 1999. 12b They discovered that Wilkinson’s catalyst, CJRh(PPh3)catalyzed the hydrothiolation of 1-octyne and benzene thiol in good yield (62-97%). EtOH was found to be the best solvent and the reaction was completed after 20 hours at 20-40 °C with the E-linear isomer formed preferentially. Some mechanistic data had been obtained and the key step of the catalytic cycle was postulated to be migratory insertion of the alkyne into the Rh-H bond (see Scheme 1 .2).12l 6 RhClL PhSH Scheme 1.2 The problem with this methodology was only benzene thiol was investigated as the thiol source and the author indicated that alkyl thiols did not work under the same conditions 12,c Our research group has recently reported that Wilkinson’s catalyst did catalyze hydrothiolation reaction using alkyl thiols with good regioselectivity of the E linear isomer, when the solvent was changed from ethanol to 1 ,2-dichloroethane (eq 1.6). 12d RSH + R1 ClRh(PPh R1SR (1.6) R = Aryl Solvent = EtCH = Alkyl = CICH2HI In 2007, Yadav and co-workers reported InBr3 to be an efficient catalyst in hydrothiolation using aryl thiols.12eAryl alkynes gave a mixture of linear products in excellent yield with the E-linear isomer favored. However, when aliphatic alkynes were R El R Rh(SPh)ClL HRh(SPh)CILH 7 used, the product was the corresponding thioacetal (see Scheme 1.3). All the reactions were completed in less than 30 minutes, but no mechanistic data were provided. (JSH I - - E:Z=7:3 PhS,,SPh 98 % n-C6H13 — n-C6H1( Scheme 1.3 1.2.2 Branched Isomer Compared with the linear adducts, the branched product is much more difficult to access, and the examples of using alkyl thiols are uncommon. In Truce’s 1956 paper, some branched product was obtained together with the linear adducts using nucleophilic sodium p-toluenethiolate, but no selectivity was reported.oa 1.2.2.1 Nucleophific Hydrothiolation The few examples of hydrothiolation using aliphatic thiols that form the branched isomer regioselectively employ nucleophilic conditions. In 2005, Oshima and co-workers found terminal alkynes with a hydroxyl group can give the branched isomer in cesium carbonate mediated hydrothiolation (see Scheme 1.4).6e 3-butyn-l-ol gave 99% of branched product exclusively (n=2). Propargyl alcohol (n=l) and 4-pentyn-1-ol (n=3) gave a mixture of Z-linear and branched adducts in good and excellent yields respectively, 8 with the branched isomer favored. However, if n=4, the yield decreased significantly, but the stereoselectivity was still the same. No reasonable explanation was given in the paper. H SC12H25 H H n1 + >==ç 85 % H ‘‘—OH C12H25S OH 74:26 - H SC12H25 n-2 OH OH 99% H — n in + H—SC12H5 (1.2eq) n=3 H SC12H2 H H fl = 1 4 H + Cl2SSOH 89:11 H SC12H2 H H ). + >=-K 36% H C12H25S H0 84:16 HO—’ Scheme 1.4 1.2.2.2 Transition Metal-Catalyzed Hydrothiolation The first work of synthesizing branched vinyl sulfides was performed by Ogawa and co-workers in 1992.12c They discovered Pd(OAc)2catalyzed hydrothiolation and provided the branched isomer as the major adduct. However, only aryl thiols and a few alkynes were investigated, no alkyl thiol was employed, and the reactions needed high temperature and prolonged reaction times. A plausible reaction mechanism was also 9 provided. Migratory insertion of alkynes into Pd-S bond was considered as the key step of the reaction (see Scheme 1.5). Pd(OAc)2+ 2ArSH -2HOAc A” Pd(SAr)2L Pd(SAr)2L R I Pd(SAr)L ____ SAr R Scheme 1.5 Hydrothiolation of benzenethiol and conjugated terminal enynes with a terminal triple bond was achieved by Bãckvall and co-workers in 1994. In each case, the triple bond was found more reactive than the double bond, and the branched diene was formed in moderate yield (41-75%). 12f However, the reaction of internal enynes was not successful and only benzenethiol was used as a thiol source. Those products can be oxidized to the sulfoxide derivatives by oxone. Furthermore, those conjugated dienes could be further functionalized by Michael addition of a nucleophile, followed by [2,3] sigmatropic rearrangement to generate the allylic alcohol (see Scheme 1.6). 10 SPh + HSPh cat. Pd(OAc)2 MeOH/H20 64% MeO0 OH MeOH [ OMe 85% Scheme 1.6 In 2007, Beletskaya and co-workers reported a novel approach for the preparation of one dimensional Pd nanoparticles with organic iigands.l2 In this approach, Pd(OAc)2 dissolved in alkyne, reacted with thiol and generated nanostructured Pd species in 85% yield at room temperature (see Scheme 1.7). Both nm- and sum-scale Pd species could be prepared depending on different reaction conditions, but only nm-scale Pd nanoparticles had high efficiency and regioselectivity for the branched isomer in hydrothiolation reactions. solution of RSH Pd(OAc)2 + R’ — Pd(OAc) Pd8 [Pd(SR)] in alkyne -HOAc SR Scheme 1.7 The hydrothiolation reaction occurred at 80-100 °C or under microwave heating. Cyclohexanethiol reacted with different terminal alkynes in good to excellent yields (75- 92%) with great regioselectivity for the branched isomer. Benzene thiol was less reactive but the regioselectivity was still good. A postulated reaction mechanism was also 60% ii provided. Aikyne coordinated to palladium, migratory inserted into the Pd-S bond and trapped by thiol to generate the product (see Scheme 1.8). This is the second report about synthesizing the branched alkyl vinyl sulfide in hydrothiolation reaction. RS RSH [Pd(SR)2] R/\ R’ Pd Pd2(SR)5 R RS Scheme 1.8 12 1.3 Previous work of our group The first example of synthesizing the branched alkyl vinyl sulfide via transition metal catalyzed hydrothiolation was reported by our group in 200512h Tp*Rh(PPh3)2(I, Tp* = tris(3 ,5-dimethylpyrazolyl)-borate, Figure 1.2) was an efficient catalyst to give the branched isomer predominantly in good to excellent yields arid selectivity. Ten examples using alkyl thiols were given. Aryl thiols were also found to generate the branched isomer preferentially, but the selectivity was lower. Because the products of the reactions using aryl thiols are readily available using other means, these reactions were not studied further. Instead, we chose to explore the use of alkyl thiols because the vinyl sulfide products are not readily available. A series of pyrazolylborate ligands, such as Tp* (tris(3,5.-dimethylpyrazolyl)borate), Bp* (bis(3 ,5-dimethylpyrazolyl)borate), Tp (trispyrazolylborate), Tp” (tris(3- phenyipyrazolyl)borate), and TpMe (tris(3 -phenyl,5-methylpyrazolyl)borate), were used to synthesize different kinds of rhodium complexes.‘2 For the catalytic activity, Bp* <Tp <Tp’< TPPhMe Tp*. Since the synthesis and purification of TpMe rhodium complex was more difficult, Tp*Rh(PPh3)2was chosen for scope and limitation investigations. A previous undergraduate student (Baldip Kang) had performed some preliminary mechanistic investigations using labeling studies)3a The reaction was believed to Figure 1.2. Tp*Rh(PPh3)Complex (I) 13 proceed via oxidative addition of the thiol, ligand exchange of triphenyiphosphine for the alkync, alkyne insertion into Rh-S bond, and reductive elimination to form the branched product and regenerate the catalyst (see Scheme 1.9). Further exploration of the reaction mechanism is underway.’31’ N H SR H- H R’ i N,, ,PPh3 PPh3 PPh3 HEER H’B N ==- I Scheme 1.9 Another important observation is that Tp*Rh(PPh3)2was found to decompose in THF and DCE if left for prolonged time, producing a complex via orthometalation of one of the phosphine ligands (eq 1.7).’ Although it formed a strained four-membered ring, this process was determined to be irreversible. This would be detrimental to a catalytic PPh3 PPh3 PPh3 14 reaction, as it would remove the active catalyst. The cyclometalation could be avoided once some nonpolar solvents were used, such as benzene and toluene. For hydrothiolation, slightly polar solvents are needed. Thus, a 1:1 ratio of toluene and DCE was found to be optimal for hydrothiolation and would preclude catalyst decomposition even if prolonged reaction times were needed. -N, PPh3 DCE (1.7) ui N’ PPh h (73%) Tp*Rh(PPh3)2was demonstrated to not only work in alkyne hydrothiolation, but also catalyze alkyne hydrophosphinylation (eq 1.8).’ Compared with hydrothiolation, in which the branched isomer was formed predominantly, it was expected to produce the same isomer for hydrophosphinylation. Upon investigation of this hypothesis, it was found that Tp*Rh(PPh3)2did catalyze alkyne hydrophosphinylation, although not as well as Wilkinson’s catalyst. In addition, the product was not the branched isomer, but the E linear adducts. It was postulated that both Wilkinson’s catalyst and Tp*Rh(PPh3)reacted with Ph2(O)H to generate the active catalytic species and that this process was more efficient with Wilkinson’s catalyst. P(O)Ph2 Ph2(O)H + R 11 + R°12 + R P(O)Ph2(1.8) branched E-Iinear Z-Iinear 15 1.4 Summary Vinyl sulfides are important synthetic intermediates in total synthesis and useful building blocks for many highly functionalized molecules. Transition metal catalyzed alkyne hydrothiolation is an efficient method to produce vinyl sulfides. Methods of forming the E- and Z- linear adducts have been investigated widely. However, most methods of making branched isomer are limited to aryl thiols. Tp*Rh(PPh3)2is a promising catalyst for alkyne hydrothiolation reaction, giving branched alkyl vinyl sulfides predominantly. Given that this process provides a useful strategy for the formation of branched alkyl vinyl sulfides, we wanted to explore the substrate scope and limitations of this catalyst. As such, the goals of this research project were to evaluate functional group tolerance, as well as steric and electronic effects in alkyne hydrothiolation catalyzed by Tp*Rh(PPh3)2. 16 Chapter 2 —Substrate Scope and Limitations of Tp*Rh(PPh3)2Catalyzing Alkyne Hydrotbiolation 2.1 Introduction Ailcyne hydrothiolation, as discussed in chapter 1, is the addition of an S-H bond across an alkynyl it-bond and is a very efficient method for the synthesis of vinyl sulfides (eq 2.1). Although aryl vinyl sulfides can be made by radical,5 nucleophilic,6and metal- catalyzed’2reactions, a general synthetic method of the branched alkyl vinyl sulfides is still not well developed. RSH SR + R,SR + R (2.1) + R1 SR R1 branched (a) E-Iinear (b) Z-Hnear (c) Our group has recently reported that Tp*Rh(PPh3)2(I, Figure 1.2)1211 and TpPle Rh(PPh3)2are excellent catalysts for alkyne hydrothiolation using alkyl thiols to generate branched alkyl vinyl sulfides.’2”In our early work, we reported ten examples of alkyne hydrothiolation. We wanted to explore the scope in greater detail. Since the synthesis and purification of the TpPl1Me rhodium complex was difficult and time consuming, Tp*Rh(PPh3)2was chosen for the scope and limitations investigation. 17 2.2 Resi1ts and Discussion A broad range of thiols and alkynes were selected for investigation. The reactions are classified into five parts: (1) hydrothiolation of benzylthiol and aryl alkynes, (2) hydrothiolation of benzylthiol and aliphatic alkynes, (3) hydrothiolation of phenylacetylene with different thiols, (4) hydrothiolation of different alkynes and n propanethiol, and (5) hydrothiolation of internal alkynes and other cases. The hydrothiolation using n-propanethiol was done by another group member (Anthony Sabarre), and some reactions from this previous work will be cited. In a typical experiment, PhCH3 (2 mL), 1 ,2-dichloroethane (DCE, 2 mL) and Tp*Rh(PPh3)2(280 mg, 0.30 mmol, 3 mol %) were combined in a 20 mL vial equipped with a magnetic stir bar and a screw cap. Thiol (11 mmol, 1.1 equiv relative to alkyne) and alkyne (10 mmol) were then added and the solution was stirred at room temperature for 2 hours. In some cases longer reaction times and higher temperatures were needed; these conditions will be noted in the text and in the experimental section. 2.2.1 Hydrothiolation of Benzylthiol and Aryl Alkynes We first examined the electronic effect ofpara-substituted phenylacetylenes (Table 2.1, entries 1-6). The electronic modifications at the para- position did not influence the reaction regioselectivity, but had a significant effect on the reaction efficiency and yield. The branched isomers were the only product of these reactions. Alkynes with electron- donating groups (entries 1-4) gave excellent yields, but those with electron-withdrawing groups (entries 5 and 6) gave lower yields. The methoxy group at meta- position (entry 7) also gave a very good isolated yield, however the yield of the reaction of ortho methoxyphenylacetylene (entry 8) was much lower even after 24 hours. There are two 18 potential explanations for these results: the methoxy group at the ortho- position could be too bulky and/or the oxygen of the ether could coordinate to rhodium. Both scenaiios would lead to slower catalysis. We chose a more sterically demanding ortho methyiphenylacetylene (entry 9) for further investigation and found that the yield was still good. Since the methyl group cannot coordinate to rhodium easily, we concluded that the coordination of oxygen to rhodium was the reason for the low reaction efficiencyand yield indicated in entry 8. An alkyne with a strongly coordinating group, 2- pyridylacetylene (entry 10), showed no reactivity at all. Table 2.1. Scope of Hydrothiolation of Aryl Alkynes with Beiizylthiol Catalyzed by I. 3 mol% I — DCE:PhCH(1 1) S Ph Ph SH + Ar— 2h,rt Ar entry8 Ar product, yield” entry8 Ar product, yield” 1 Me2N—-[- Ia, 90% F3C—(J—— 6a, 40% 2c H3CO- 2a, 93% 7 7a, 83% OCH3 3 H3C—’-— 3a, 91% 8 8a, 55% 4C H—K--— 4a, 90% 9 9a, 85% Br—(D-— 5a, 67% 10 0% a Reaction conditions: 10 mmol alkyne, 11 mmol thiol, 4 mL of 1:1 DCE:PhCH3,and 0.3 mmol (3 mol %) catalyst, at room temperature for 2 h, unless otherwise noted. b Isolated yields. C Ref 12h, d An additional 5-10% of an unidentified byproduct was observed. Reaction time 24 h. 19 In order to get more information about why 2yridylacetylene did not react, we conducted the following reaction: T*Rh(PPh3)2(93 mg, 0.1 nirnol) was dissolved in d8- = toluene (1 mL), and 2-pyridylacetylene (0.1 mL, 1.0 mmol) was then added. After 30 minutes, the color of the solution changed from orange to black, and the ‘P N specum showed that the PPh3 sigual Tp*Rh(PPh3)2(642.92, d, J = 175.6 Hz) had vanished and both a new doublet (6 45.90, Jp = 124.7 Hz) and new singlet (6 -4.56) appeared. A rhodium hydride species (6 -14.68, JRh-H = 20.5 HZ,JPH = 17.6 Hz) was also detected in the ‘H NMR spectrum. The solution was transferred to a 5 mL vial, layered with 2 mL of hexanes; crystals suitable for X-ray diffraction formed after 2 days at room temperature. The ORTEP diagram (Figure 2.1) indicated that the terminal C-H bond of alkyne was activated and a rhodium hydridoacetylide (complex II) was generated. The bond lengths and angles of complex II was very similar to other reported rhodium hydridoacetylieds.’4 We have previously reported that such a C-H activation process irreversible and that the resulting complex has no reactivity in alkyne hydrothiolation reactions.14In addition, we have found that hydrothiolation proceeds by S-H activation, followed by ailcyne migratory insertion. 13a In other words, S-H activation must be faster than C-H activation. The same phenomenon was also observed in the catalytic reaction. Thus, we thought since that binding of pyridine suppresses thiol coordination. As a result, 2- pyridylacetylene is in close proximity to the metal center, which facilitates C-H activation, thereby suppressing catalysis. 20 C15 C13 cii C12 C14 C39 C40 H2 C5 C34 do Ni Hf Rh1 N3 I j___YC33 C16 C30 Cl 9 C20 C24 Figure 2.1. ORTEP diagram of complex II. Thermal ellipsoids are drawn at the 50% probability level. Hydrogen atoms, except for the B-H hydrogen and the phenyl groups of PPh3, are excluded for clarity. Selected bond lengths (A), angles (deg): Rh-P = 2.2732(5), Rh-C(34) = 1.9627(17), Rh-H = 1.46(2), C(34)-C(35) = 1.212(2), C(34)-Rh(l)-P(l) = 88.72(5), C(34)-Rh(l)-H(1) = 83.8(9), P(l)-Rh(1)-H(1) = 88.1(8). 2.2.2 Hydrothiolation of Benzylthiol and Aliphatic Alkynes Hydrothiolation of aliphatic alkynes was studied next. Compared to aromatic alkynes, the reactions of aliphatic alkynes need longer time to complete, but the yields and selectivities were still very good. 3-Phenyl-1-propyne (Table 2.2, entry 1), 5- hexynenitrile (entry 2), 5-chloro- 1 -pentyne (entry 3), and 1 -octyne (entry 4) reacted with benzyl thiol in good-to-excellent yields. The lower yield of phenyl propargyl ether (entry 21 5) could also be attributed to the coordination of oxygen to rhodium. In addition, the product of entry 6 and its oxidized derivatives may be suitable for Diels-Alder reactions. Table 2.2. Scope of Hydrothiolation of Aliphatic Alkynes with Benzylthiol Catalyzed by I. 3 mol% I PhSH + R DCE:PhCH(1 1) R entrya R time (h) product, yield” entrya R time (h) product, yield” I 2 3 4 24 48 24 16 24 6c 10 15a,81% 7C t-Bu-- 24 16a, 63% 8 TMS-- 2 9 EtOC-[ 2 lOa,85% NC- 11 a, 88% Cl_\ 12a, 90% 17a:17b:17c n-C6H13j - 13a, 92% = 6:3:2, 88% 18b:18c5 PhO\ 14a, °“ = 2:1, 68% a Reaction conditions: 10 mmol alkyne, llmniol thiol, 4 mL of 1:1 DCE:PhCH3,and 0.3 mmol (3 mol %) catalyst, it b Isolated yields. C Ref 1 2h. The products of the alkynes containing propargylic protons (entries 1-4) can isomerize under acidic conditions. For example, when benzyl(1-benzylvinyl)sulfane (lOa) was let to stand in chloroform overnight, 13% of Z- and 25% of E- internal vinyl sulfide were found (eq 2.2).12h1 This phenomenon could be avoided if less acidic solvents were used for chromatography and NMR spectroscopic studies (eq 2.3). 22 SPh CHCI3 SPh S’Ph I Ph Ph + Ph + Ph Ph (2.2) lOa 62%lOa 13%lOb 25%lOc S Ph Benzene no isomerization (2.3) I Oa The effect of sterics was also investigated. The reaction of 3 ,3-dimethyl- 1 -butyne (entry 7) took 24 hours to go to completion and formed the branched isomer in moderate yield, indicating that sterically bulky groups can somewhat slow catalysis. If trimethylsilyl acetylene (entry 9) was used, the reaction was complete in 2 hours, but the regioselectivity was lowered, with 40% of the the linear isomers being formed. It is not clear why the selectivity was lowered, but could be due to the beta-silicon effect. Trimethylsilyl groups are useful functional groups that can be easily deprotected or further functionalized in Hiyama’6 cross-coupling. The hydrothiolation of ethyl propiolate gave a mixture of E- and Z-linear isomers in a 2:1 ratio.17 No branched product was formed in this case. This result was likely due to the strongly electron withdrawing ester group, which activates the beta-position of the alkene toward nucleophilic attack. The use of DBU generates a 1:2 ratio of E- and Z-linear isomers after 2 h at room temperature. Therefore, the result using Tp*Rh(PPh3)2is not simply due to competing Michael addition. Several competing mechanisms are possible. 23 2.2.3 Hydrothiolation of Phenylacetylene with Different Thiols Given that a variety of alkynes were found to be effective in hydrothiolation, we next examined the substrate scope of thiols that participate in this reaction. Besides benzyl thiol (Table 2.3, entry 1), a variety of alkyl thiols reacted with phenylacetylene in good yields, including both unhindered (entry 2) and sterically bulky (entry 3) groups. Many functional groups were well tolerated, such as heteroaromatic rings (entry 4), ethers (entry 5), esters (entry 6) and amines (entry 7). However, the reaction of thiols with a carboxylic acid (entry 8) or allyl group (entry 9) failed. In the latter case, since the n-propanethiol (entry 2) reacted with phenylacetylene successfully, we thought the double bond should play an important role in this process. This was disappointing, because if the allyl mercaptan (entry 9) reacted successfully, the product could undergo several transformations, such as thio-Cope’8 and Mislow-Evans’9rearrangements (upon oxidation to the sulfoxide). 24 Table 2.3. Scope of Hydrothiolation of Phenylacetylene with Different Thiols Catalyzed by I. 3 mol% I SR RSH + Ph — ____ DCE:PhCH3(1:1) L 2 h, rt Ph” entrya R product, yieId’ entrya R product, yield” 1c Ph Ia, 90% 06 23a, 80% BuO 2’ 19a, 74% 7e Me2N 24a, 65% 3C 20a, 78% 4 21a, 75% H02C/ 0% 5 Ph0-’. 22a, 70% ge 0% a Reaction conditions: 10 mmol alkyne, 11 mmol thiol, 4 mL of 1:1 DCE:PhCH3,and 0.3 mmol (3 mol %) catalyst, at rt for 2 h, unless otherwise noted. b Isolated yields. C Ref 12h. d Ref 3f e Reaction time: 24 h. Further insight was obtained from the following stoichiometric reaction. A d8- toluene (1 mL) solution of Tp*Rh(PPh3)2(93 mg, 0.1 mmol) was placed in a NMR tube, and allyl mercaptan (0.08 mL, 1.0 mmol) was added by syringe. After 30 minutes, the 31P NMR spectrum showed that the PPh3 signal Tp*Rh(PPh3)2(6 42.92, d, J = 175.6 Hz) disappeared and a new singlet (6 -4.56) appeared, which indicated that both of the PPh3 ligands had dissociated. However, no rhodium hydride species were found in the ‘H NMR spectrum, although the methylene resonance of thiol changed from a doublet of 25 doublets (ö 3.16, J 7.0 Hz, J= 7.0 Hz) to a doublet (ö 2.78, J= 6.9 Hz). This data could indicate that diallyl sulfide formed in this process, but no further information can be provided from GC-MS analysis. Nonetheless, the data showed that the allyl mereaptan did react with Tp*Rh(PPh3)2,but not in the same way that other thiols react. 2.2.4 Hydrothiolation of Different Alkynes and n-Propanethiol The catalytic hydrothiolation of n-propanethiol and various alkynes was investigated by Anthony Sabarre.3Similar to the reactions of benzyl thiol, all reactions proceeded with high selectivity of branched products. Likewise, the reactions of para-substituted phenylacetylenes with benzyl thiol followed the same trends. All the hydrothiolation products proved to be suitable for Kumada-type cross-coupling to generate 1,1- disubstituted oleflns3,20 2.2.5 Hydrothiolation of Internal Alkynes and Other Cases The catalytic hydrothiolation reactions of internal alkynes were found to be much more difficult to achieve than with terminal alkynes. Longer reaction times were always needed and sometimes high temperature was necessary (Table 2.4). While the reaction between cyclopentyithiol and diphenylacetylene proceeded in excellent yield providing a single isomer (entry 1), only a trace of the desired product can be found in the reaction using benzyl thiol (entry 2). Cyclotrimerization’occurred when 3-hexyne was used, and the yield of expected product was only 32 % (entry 3). The reaction of 1-phenyl-1- propyne gave a moderate yield and favored the less-hindered isomer as product (entry 4). 26 Table 2.4. Scope of Hydrothiolation of Internal Alkynes Catalyzed by I RSH + R1=R2 3 mol% I DCE:PhCH3(1:1) product entrya R alkyne temperature, time product yield” IC Ph — Ph 80 °C, 24 h S Ph Ph 25a, 94% Et El Et Ph El Me Reaction conditions: 10 mmol alkyne, 11 mrnol thiol, 4 mL of 1:1 DCE:PhCH3,and 0.3 mmol (3 mol %) catalyst. b Isolated yields. C Ref 12h d Yield based on 1H NMR analysis. Finally we achieved a successful hydrothiolation of 1,6-hexanedithiol and 2.2 equivalents of 4-methoxyphenylacetylene and obtained 80% of desired product after 24 hours at room temperature (eq 2.4). None of the mono-addition product was detected, although this species is likely an intermediate in the formation of 28a. + H3CO—€J?—-_ 3 mol% Tp*Rh(PPh3)2 DCE:Tolene(1:1) 24h, rt, 80% Ph :ii Ph2 Ph 3 Ph 4C Ph) rt, 24 h rt, 24 h trace 26a, 32%d 50°C,4h Ph + S—\ 27a:27b= Ph 1 :3.5,7OiodPh’ (2.4) 28a 27 2.3 Experimental Procedures 2.4.1 General Methods Manipulation of organometallic compounds was performed in a nitrogen-filled Vacuum Atmospheres drybox (02 < 2 ppm). NMR spectra were recorded on Bruker Avance 300 or Bruker Avance 400 spectrometers. ‘H, ‘3C and 31P chemical shifts are reported in parts per million and referenced to residual solvent. Coupling constant values were extracted assuming first-order coupling. The multiplicities are abbreviated as follows: s = singlet, d = doublet, t triplet, quin = quintet, m multiplet). 31P{1H} NMR spectra were referenced to an external 85% H3P04 standard, and ‘9F NMR spectra were referenced to CFC13 standard. All spectra were obtained at 25 °C. Elemental analyses were performed using a Carlo Erba Elemental Analyzer EA 1108. Mass spectra were recorded on a Kratos MS-50 mass spectrometer. 2.4.2 Materials and Methods. Hexanes (boiling range 68.3-69.6 °C), CH21 Et20, THF, benzene, PhCH3 and DCE (1 ,2-dichloroethane) were dried by passage through solvent purification columns.22 CDC13 was distilled from P205 and was degassed prior to use. C6D was purified by vacuum transfer from Nalbenzophenone. All organic reagents were obtained from commercial sources and used as received. Wilkinson Catalyst was purchased from Strem Chemicals and was used without further purification. Tp*Rh(PPh3}2(1)23 was prepared as previously reported. 12j 28 2.4.3 General experimental procedure for hydrothiolation. Tp*Rh(PPh)2(280 mg, 0.30 mmol, 3 mol %), PhCH3 (2 mL), DCE (2 mL) were combined in the glove box in a 20 mL vial equipped with a magnetic stir bar and a screw cap. Thiol (11 mmol) and alkyne (10 mmol) were added sequentially. The vial was removed from the glove box. The vial was then wrapped in aluminum foil and the solution was stirred at the indicated temperature and monitored by TLC. After the reaction was completed, the resulting mixture was filtered through silica gel, washed by hexanes, concentrated under vacuum. Flash chromatography (Si02, hexanes or a mixture of hexanes: EtOAc as eluent) provided the product. Note: The reactions proceed very slowly in the absence of the catalyst, indicating that background reactions are minimal. The addition of a non-nucleophilic base (2,2-lutidine) does not impede or improve the reaction.12h1 Analytical data for 2a, 4a, 13a, 15a, 16a, 19a, 20a, 25a, and 27a,b were previously reported. 12h 29 XSH + Me2N-Q-- 3 ;:.;:2 QQ 2h,rt,90% Ia Benzyl(1-(4-N,N-dimethyphenylvinyl)sulfane (la): Yellow oil, 90% yield. Column chromatography conditions: 20:1 hexanes:EtOAc and 3 % Et3N. ‘H NMR (CDC13,300 MHz): ö 7.47 (d, 2H, J= 8.7 Hz), 7.31 — 7.23 (m, 5H), 6.71 (d, 2H, J= 9.1 Hz), 5.36 (s, 1H), 5.08 (s, 1H), 3.90 (s, 2H), 2.99 (s, 6H), 1.55 (H20).‘3C{1H} NMR (CDCI3, 100 MHz): 3 149.3, 145.7, 138.5, 129.9, 129.4, 129.1, 128.2, 128.0, 113.0, 110.1, 41.5, 38.2. HRMS (El) mlz calcd forC17H9SN: 269.1238; found: 269.1236. Anal. calcd forC17H9SN: C, 75.79; H, 7.11; N, 5.20; found: C, 75.72; H, 7.16; N, 5.53. 30 ‘H NMR (CDC13,300 MHz) s-r Me2N’- Ia 9.5 9.0 8.5 80 7.5 7.0 6.5 6.0 5.5 5.0 45 45 3:5 30 25 2.0 1.5 1.0 0.5 Chen,il Shift (ppm) ‘3C NMR (CDC13,100 MHz) r0 Me2N Ia I..l] 102 184 176 168 160 152 144 136 128 120 112 1ó4 9 8 8072645646403224 l6 Chomical Shift (ppm) 31 OSH + 3rn%Tp*Rh(pph3)2 2h,rt,91% 3a Benzyl(1-p-tolylvinyl)sulfane (3a): Yellow oil, 91% yield. Column chromatography conditions: 20:1 hexanes:EtOAc. ‘H NIvIR (CDC13, 300 MHz): ö 7.47 (d, 2H, J = 8.2 Hz), 7.34 — 7.27 (m, 5H), 7.20 (d, 2H, J = 7.8 Hz), 5.47 (s, 1H), 5.21 (s, 1H), 3.93 (s, 2H), 2.40 (s, 3H). ‘3C{’H} NMR (CDC13, 100 MHz): ö 145.9, 139.4, 138.1, 137.6, 130.1, 130.0, 129.5, 128.2, 128.1, 112.2, 38.2, 22.2. HRMS (El) mlz calcd for C,6HS: 240.0967; found: 240.0973. Anal. calcd for C,7H2SN: C, 79.95; H, 6.71; found: C, 79.73; H, 6.62. 32 V 1H NMR (CDC13,300 MHz) sAN L3a CheniI Shift (ppn) ‘3c NMR (CDC13,100 MHz) SN CherniI Shift (ppn) 33 + Br—(— 3rn01%Tp*Rh(pph3)2 2h,rt,67% Br 5a Benzyl(1-.(4-bromophenyl)vinyl)sulfane (5a): Pale yellow oil, 67% yield. Column chromatography conditions: 20:1 hexanes:EtOAc. ‘H NMR (CDC13, 300 MHz): 8 7.48 (d, 2H, J = 8.7 Hz), 7.41 (d, 2H, J = 8.7 Hz), 7.32 — 7.22 (m, 5H), 5.44 (s, 1H), 5.23 (s, 1H), 3.88 (s, 2H), 1.54 (H20).‘3C{’H} NMR (CDC13,75 MHz): 6 144.0, 138.5, 136.9, 131.7, 129.0 (two peaks overlaping), 128.7, 127.4, 122.6, 112.9, 37.3. HRMS (El) mlz calcd forC15H3S79Br: 303.9921; found: 303.9919. Anal. calcd forC,5H3S79Br: C, 59.02; H, 4.29; found: C, 58.64; H, 4.40. 34 sThI Br’ 5a 95 90 85 80 7 70 65 60 55 50 45 40 35 3.0 25 20 Choi 0501 (pp,) l3 NMR (CDC13,75 MHz) 1flflMMIR!$L1IIIUflhIIH1 ‘‘‘ 1à2 14 1761681601521441361281011210496 88 80 72&1 56 48 40 32 24 16 8 Chn4I 0148 (ppo) ‘H NMR (CDC13,300 MHz) 1.5 1.0 0.5 rT0 Br’- 5a 35 ftfSH + F3C_4J__ DC; Ph 2h,rt,40% F3C 6a Benzyl(1-(4-(trifluoromethyl)phenyl)vinyl)sulfane (6a): Yellow oil, 40% yield. Column chromatography conditions: 20:1 hexanes:EtOAc. ‘H NMR (CDC13,300 MHz): 6 7.65 —7.58 (m, 4H), 7.33 —7.23 (m, 5H), 5.52 (s, 1H), 5.31 (s, 1H), 3.90 (s, 2H), 1.53 (H20). ‘9F NMR (CDC13,282 MHz): 6 -63.1 (d, J 4.2 Hz).‘3C{’H} NME. (CDC13,100 MHz): 6 143.8, 143.0, 136.6, 130.4 (q, J= 33.0 Hz), 128.8, 128.5, 127. 5, 127.3, 125.4 (q, J = 3.8 Hz), 124.1 (q, J = 272.2 Hz), 113.9, 37.3. HRMS (El) m!z calcd for C16H3SF3:294.0690; found: 294.0702. Anal, calcd forC16H3SF3:C, 65.29; H, 4.45; found: C, 64.94; H, 4.36. 36 1H NMR (CDC13,300 MHz) s--- F3C 6a -ri_.r r s.-.- :rrr. LJ.Lr.it V V . t.ui V —rr-r ri, ., jUL1’’’’ 192184176166 160152 144 136128 120112 164 86 8580 72 6456 4540 3224 16 8 Chen4I Shift (ppm) 95 90 85 80 75 70 65 60 50 50 45 40 35 30 25 20 15 10 05 Chon*I Shift (pprmm) ‘3c APT NMR (CDC13,100 MHz) F3C- 6a 37 +3rno(%Tp*Rh(pph3)2 H3CO 2 h, rt, 83% OCH3 7a Beuzyl(1-(3-methoxyphenyl)vinyl)sulfane (7a): Yellow oil, 83% yield. Colunm chromatography conditions: 20:1 hexanes:EtOAc. ‘H •NMR (CDC13, 300 MHz): ö 7.32 — 6.90 (m, 9H), 5.50 (s, 1H), 5.25 (s, 1H), 3.93 (s, 2H), 3.84 (s, 3H). ‘3C{’H} NMR (CDC13,75 MHz): ö 159.8, 145.1, 141.0, 137.2, 129.6, 129.1, 128.7, 127.3, 119.9, 114.4, 112.9, 112.2, 55.5, 37.4. HRMS (El) mlz calcd forC16H,6S0: 256.0922; found: 256.0921. Anal. calcd forC16HS0: C, 74.96; H, 6.27; found: C, 74.59; H, 6.27. 38 ‘H NMR (CDC13,300 MHz) OCH3 a ““ ““ ChrnicaI Shift (ppn) ‘3C NMR (CDC13,75 MHz) OCH3 7a 1ir I -jJunILMJ ii thJK; &i tJi ttt 192 194 176 168 160 152 144 136 128 120 112 104 96 88 80 77 64 56 48 40 32 24 16 8 Chornii Shift (ppn) 39 +:::;3)2 JL1IDJ OCH3 24 h, ‘ OCH3 Ba Benzyl(1-(2-methoxyphenyl)vinyl)sulfane (8a): Pale yellow oil, 55% yield. Column chromatography conditions: 20:1 hexanes:EtOAc. ‘H NMR (CDC13,400 MHz): ö 7.31 — 7.21 (m, 7H), 6.96 — 6.90 (m, 2H), 5.37 (s, 1H), 5.34 (s, 1H), 3.90 (s, 2H), 3.84 (s, 3H). 13C{H} NMR (CDC13, 100 MHz): ö 157.1, 142.7, 138.1, 131.5, 130.4, 129.9, 129.4, 128.0, 121.6, 121.5, 114.4, 112.29, 56.8, 38.2. HRMS (El) mlz calcd for C16HS0: 256.0922; found: 256.0923. Anal. calcd for C16HSO: C, 74.96; H, 6.27; found: C, 74.79; H, 6.35. 40 9.5 9.5 8.5 8.0 7.8 7.0 6:5 6.0 5.5 5,0 4.5 4.0 3.5 3.0 2:5 2.0 1.5 1.0 0.5 Chnil Shift (ppm) ‘3C NMR (CDC13,100 MHz) ç-cOCH3 8a :‘ b.88 - ,:.‘,.,o’o.,t’T’-. ,-,,,.,- -9,b._ 192 084 076 168 160 152 144 ‘ 136 128 120 112 104 96 88 60 72 64 56 48 40 32 24 16 8 ChemftI Shift (pp,n) ‘H NMR (CDC13,400 MHz) SQ I I I L 1 41 JSH + Q— 3;.:3)22h,rt,85% 9a Benzyl(1-o-tolylvinyl)sulfane (9a): Pale yellow oil, 85% yield. Column chromatography conditions: 20:1 hexanes:EtOAc. ‘H NMR (CDC13, 400 MHz): 7.36 — 7.22 m, 9H), 5.34 (s, 1H), 5.15 (s, 1H), 3.9.1 (s, 2H), 2.38 (s, 3H). ‘3C{’H} NMR (CDC13,100 MHz): ö 145.9, 140.4, 138.0, 137.1, 131.3, 130.5, 129.9, 129.5, 129.1, 128.2, 126.6, 112.5, 37.9, 20.7. HRMS (El) mlz calcd for C,6HS: 240.0973; found: 240.0976. Anal. calcd forC,6H16S: C, 79.95; H, 6.71; found: C, 80.32; H, 6.77. 42 ‘H NMR (CDC13,400 MHz) CC] ________- -______ - . ____ 9.5 9.0 9.5 8.0 7.5 7.0 6.5 6.0 6.5 5.0 4.5 4.0 35 30 2.5 2.0 1.5 1.0 0.5 ChemiaI ShOt (ppn) ‘3C NMR (CDC13,100 MHz) 192 184 176 168 160 152 14 k 18 120 112 104 96 86 60 72 64 56 46 40 • 32 24 16 8 Chen,il Shill (pp,) 43 +rndTp*Rh(pph) 24h,rt,85% wa Benzyl(1-benzylvinyl)sulfane (lOa): Pale yellow oil, 85% yield. Column chromatography conditions: 20:1 hexanes:EtOAc. 1H NMR (C6D, 400 MHz): 6 7.27 — 7.10 (m, 1OH), 5.06 (s, 1H), 4.89 (s, 1H), 3.73 (s, 2H), 3.52 (s, 2H). ‘3C{’H} NMR (C6D, 100 MHz): 6 146.1, 139.2, 137.3, 129.7, 129.5, 129.0, 128.9, 127.6, 127.1, 108.5, 44.3, 37.0. HRMS (El) m!z calcd forC16HS: 240.0973; found: 240.0967. Anal. calcd forC16HS: C, 79.95; H, 6.71; found: C, 79.83; H, 6.71. 44 1H NMR (C6D,400 MHz) I Oa __ I __ 9.5 9.0 85 8.0 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 C0ernioI Shift (ppm) ‘3c NMR (C6D,100 MHz) I Oa ....- ... . . 192 184 176 168 160 152 144 136 128 120 112 104 96 88 80 72 64 56 46 40 32 24 16 8 ChemiI Shift (ppm) 45A 3 mol% Tp*Rh(PPh3)2SH + NC DCE:PhCH(1 1) NC 48h,rt,88% ha Benzy1(3-cyanopropy1viny1su1fane (ha): Pale yellow oil, 88% yield. Column chromatography conditions: 10:1 hexanes:EtOAc. ‘H NMR (C6D, 400 MHz): ö 7.24 — 7.09 (m, 5H), 4.90 (s, 1H), 4.71 (s, 1H), 3.64 (s, 2H), 2.01 (t, 2H, J = 7.1 Hz), 1.48 (t, 2H, J— 7.1 Hz), 1.35 (m, 2H).‘3C{’H} NMR (C6D, 100 MHz): ö 144.1, 137.3, 129.4, 129.1, 127.8, 108.7, 36.7, 36.4, 38.7, 24.7, 15.9. HRMS (El) mlz calcd for C13H,5SN: 217.0925; found: 217.0926. Anal. calcd for C13H5SN: C, 71.84; H, 6.96; found: C, 71.87; H, 7.12. 46 ‘H NMR (C6D,400 MHz) NC-Aj’1() I Ia !“ Chemical Shift (ppm) ‘3C NMR (C6D,100 MHz) NCtQ1C) ha 4M$U$*JflI$ WI I$IMI*U flU flfliUJwPIVWP9flflLflflLE Nfl øMI 192 14 6 1S ISP 152144136128120112 1Ô4 86 88 80 7284 5648403224168 Chemical Shift (ppm) 47 3 mol% Tp*Rh(PPh3)2SH + CI DCE:PhCH (1:1) 48 h, rt, 90% I 2a Benzyl(3-chloropropylvinyl)sulfane (12a): Pale yellow oil, 90% yield. Column chromatography conditions: 20:1 hexanes:EtOAc. ‘H NMR (C6D, 400 MHz): 6 7.25 — 7.07 (m, 5H), 4.99 (s, 1H), 4.76 (s, 1H), 3.69 (s, 2H), 3.17 (t, 2H, J = 6.5 Hz), 2.24 (t, 2H, J— 7.4 Hz), 1.79 (m, 2H).‘3C{’H} NMR (C6D, 100 MHz): 6 145.3, 137.8, 129.9, 129.5, 128.2, 108.5, 44.6, 37.2, 35.4, 32.4. HRMS (El) m!z calcd forC12H,5S371: 228.0554; found: 228.0552. Anal. calcd for C,2H5SCJ: C, 63.56; H, 6.67; found: C, 63.90; H, 6.69. 48 ‘H NMR (C6D,400 MHz) CL—..-% LJ I 2a _____ L_____ -.__ ____ 95 90 85 80 75 70 65 60 55 55 45 40 35 30 25 20 15 10 05 ChomioI Shift (ppn) ‘3C NMR (C6D,100 MHz) C.!X) I 2a 092154 176 168160 152 144 136 128 120 112 1Ô4 96 66 60 72 64 40 322416 8 Chemical Shift (ppnl) 49 SH + PhO 3rn%Tp*Rh(pph3)2 PhO 24 h 40°C, 33% 14a Benzyl(phenoxymethylvinyl)sulfane (14a): Pale yellow oil, 33% yield. Column chromatography conditions: 20:1 hexanes:EtOAc, H NMR (CDCJ3, 300 MHz): ö 7.39 — 7.24 (m, 7H), 6.99 — 6.89 (m, 3H), 5.48 (s, 1H), 5.12 (s, 1H), 4.58 (s, 2H), 4.01 (s, 2H), 1.55 (H20).‘3C{’H} NMR (CDC13,100 MHz): 159.3, 141.9, 137.6, 130.4, 129.9, 129.6, 128.3, 122.2, 115.6, 112.2, 71.6, 37.5. HRMS (ESI) m/z calcd for C16HS0: 257.1000; found: 257.0992. Anal. calcd for C16HS0: C, 74.96; H, 6.29; found: C, 75.13; H, 6.36. 50 ‘H NMR (CDC13,300 IvNz) PhO%Q I 4a r” Chemical Shift (ppm) 3C APT NMR (CDC13,100 MHz) I 4a 12 144 176 186 160 152 144144 i4o i4o 12 144 96 48 dv a 44 dv 40 4b 32 24 18 4 Chemical Shift (ppm) 51 I 17a JSH + —Si— 2 h, rt, 88% (A:B:C6:3:2) I 7c Mixture of benzyl(1-trimethylsilylvinyl)sulfane (17a), (E)-benzyl(2- trimethylsilylvinyl)sulfane (17b), and (Z)-benzyl(2-trimethylsilylvinyl)sulfane (17c): Yellow oil, 88% yield, 6:3:2 mixture of 17a and 17b and 17c. Column chromatography conditions: 20:1 hexanes:EtOAc. ‘H NMR (CDC13, 300 MHz): 7.38—7.23 (m, 27.5H: 15H: 5H 17a, 7.5H: 5H 17b and 5H: 5H 17c), 6.85 (d, 1H: 1H 17c, J— 13.25Hz), 6.55 (d, l.5H: 1H 17b, J= 17.8 Hz), 5.79 (d, l.5H: 1H 17b, J= 17.8 Hz), 5.62 (d, 1H: 1H.17c, J= 13.3 Hz), 5.45 (s, 3H: 1H 17a), 5.44 (s, 3H: 1H 17a), 3.96 (s, 9H: 6H: 2H 17a and 3H: 2H 17b), 3.90 (s, 2H: 2H 17c), 0.19 (s, 27H: 9H 17a), 0.14 (s, 9H: 9H 17c), 0.06 (s, 13.5H: 9H, 17b), 1.54 (H20). 13C{’H} NMR (CDC13,75 MHz): 6 147.7, 136.8, 129.1, 128.7, 127.3, 115.1, 35.6, -1.4. HRMS (El) m!z calcd for C12H,7SSi (mixture of isomers): 222.0899; found: 222.0896. Anal. calcd forC,2H8SSi (mixture of isomers): C, 64.80; H, 8.16; found: C, 65.05; H, 8.21. 52 ‘H NIvIR (CDC13,300 MHz) + —I I 7a I 7b + I 7c 95 90 8:5 50 4.5 4. C0o S1i0 (ppn) ‘3C NMR (CDC13,75 MHz) + 17a I 7b 3.5 3.0 2.5 2.0 1:5 1.0 5.5 + I 7c UJJA u’iiiirnj wnRurJrInhINI( iw .ppiiii _ii jiiflIfl1$lI1P1I*. 192 184 176 168 160 152 144 136 128 120 112 104 98 88 80 72 64 56 4 40 32 24 16 8 5 4 C04n*J 51881 (ppn) I— 53 os SH + — 3 mol% Tp*Rh(PPh3)2 QEt 18b - EtC — DCE:PhCH (1:1) + 2h,rt,68%(B:C=2:1) — IQEtS I 8c (E)-benzyl(2-ethyl carbonovinyl)sulfane (18b) Yellow oil, 40% yield. Column chromatography conditions: 20:1 hexanes:EtOAc. ‘H NMR (CDC13, 300 MHz): 7.68 (d, 1H, J= 15.1 Hz), 7.35 — 7.31 (m, 5H), 5.79 (d, 1H, J= 15.5 Hz), 4.17 (q, 2H, J= 7.3 Hz), 4.02 (s, 2H), 1.27 (t, 3H, J 7.3 Hz), 1.54 (H20).‘3C{’H} NMR (CDC13,75 MHz): 165.37, 146.07, 135.63, 129.0, 128.94, 127.90, 114.63, 60.41, 36.75, 14.47. HRMS (El) rn/s calcd forC12H4S02:222.0715; found: 222.0719. Anal. calcd for C12H,4S02:C, 64.83; H, 6.35; found: C, 64.94; H, 6.42. 54 ‘H NMR (CDC13,300 MHz) QEt 18b Chemical Shift (ppm) l3 NMR (CDC13,75 MHz) OEt 18b 192 184 176 168 160 152 144 136 19 120 112 104 96 98 80 72 64 56 48 40 32 24 16 8 Chon4eal Shift (ppm) 55 OSH + 3rn%Tp*Rh(pph3)2 2h, rt, 75% 21a 2-((1-Phenylvinylthio)methyl)furan (21a): Yellow oil, 75% yield. Column chromatography conditions: 20:1 hexanes:EtOAc. ‘H NMR (CDC13, 300 MHz): 6 7.56 — 7.53 (m, 2H), 7.39 — 7.33 (m, 4H), 6.29 — 6.27 (m, 1H), 6.10 — 6.09 (m, 1H), 5.49 (s, 1H), 5.31 (s, 1H), 3.88 (s, 2H), 1.54 (H20). 13C{’H} NMR (CDC13,75 MHz): 6 150.8, 144.4, 142.2, 139.2, 128.6, 128.5, 127.5, 113.5, 110.6, 107.8, 31.1. HRMS (El) m!z calcd forC,3H2S0: 216.0609; found: 216.0606. Anal. calcd forC,3H2S0: C, 72.19; H, 5.59; found: C, 72.45; H, 5.60. 56 ‘H NMR (CDC13,300 MHz) - 21a •• 1 9 99 Chemical Shift (ppm) ‘3C NMR (CDC13,75 MHz) 21a lIEIIdfl M........ 1w , 192 194 176 168 160 152 144 136 128 120 112 104 06 88 80 72 64 86 48 40 32 24 16 8 Chemical Shift (ppm) 57 PhQSH + r__=_ rnOWOT2 . 2h,rt,70% 22a (2-Phenoxyethyl)(1-phenylvinyl)sulfane (22a): White solid, 70% yield. Column chromatography conditions: 20:1 hexanes:EtOAc. 1H NMR (CDC13, 300 MHz): 6 7.58 — 7.55 (m, 2H), 7.38 — 7.34 (m, 2H), 7.28 — 7.23 (m, 3H), 6.96 — 6.92 (m, IH), 6.84— 6.81 (m, 2H), 5.51 (s, 1H), 5.36 (s, 1H), 4.12 (t, 2H, J= 7.1 Hz), 3.03 (t, 2H, J= 7.1 Hz), 1.54 (H20).‘3C{1H} NMR (CDC13, 75 MHz): 6 158.5, 144.1, 139.3, 129.6, 128.8, 128.6, 127.5, 121.2, 114.7, 113.0, 66.4, 30.9. HRMS (El) mlz calcd forC16HS0: 256.0922; found: 256.0921. Anal. calcd for C16HS0: C, 74.96; H, 6.29; found: C, 74.58; H, 6.52. 58 ‘H NMR (CDC13,300 MHz) S Q2a Chonlcal Shift (ppn) l3 NMR (CDC13,75 MHz) 22a sr*mu ii i w. .a $iZIU 0. QIIJIÜI$ :i$ 12 184 176 168 160 152 14 136 128 120 112 104 96 68 80 72 64 56 46 40 32 24 16 Chon3aI Shift (ppn) 59 00 / \ 3 mol% Tp*Rh(PPh3)2 s 0”Bu Bu0’SH —- DCE:PhCH(i:1) 2h,rt,80% 23a Butyl 3-(1-phenylvinylthio)propanoate (23a): Yellow oil, 80% yield. Column chromatography conditions: 20:1 hexanes:EtOAc. ‘H NMR (CDC13, 300 MHz): 6 7.55 — 7.32 m, 5H), 5.51 (s, 1H), 5.27 (s, 1H), 4.09 (t, 2H, J= 6.6 Hz), 2.93 (t, 2H, J= 7.3 Hz) , 2.61 (t, 2H, J 7.3 Hz), 1.61 (m, 2H), 1.54 (H20), 1.37 (m, 2H), 0.93 (m, 3H). ‘3C{’H} NMR (CDC13,75 MHz): 3 172.0, 144.1, 139.4, 128.7, 128.6, 127.4, 112.5, 64.8, 33.9, 30.8, 27.1, 19.3, 13.9. HRMS (El) rn/z calcd for C,5H20S:264.1184; found: 264.1185. Anal. calcd forC,5H20S:C, 68.14; H, 7.62; found: C, 68.00; H, 7.36. 60 1}{ NMR (CDC13,300 MHz) S-’OBu LJ 23a ChenioI Shift (ppn) l3 NMR (CDC13,75 MHz) S O”Bu 23a 192 164 176 168 160 152 144 136 128 120 112 104 96 98 80 72 64 56 48 40 32 24 16 8 Chemi6l Shift (ppm) 61 +3rno1%Tp*Rh(pPh3)2 24 h, rt, 65% 24a N,N-dimethyl-2-(1-phenylvinylthio)ethanamine (24a): Yellow oil, 65% yield. Column chromatography conditions: 20:1 hexanes:EtOAc and 3 % Et3N. 1H NMR (CDC13,400 MHz): 3 7.56 — 7.33 (m, 5H), 5.47 (s, 1H), 5.23 (s, 1H), 2.81 (t, 2H, J= 7.4 Hz), 2.57 (t, 2H, J= 7.4 Hz) , 2.25 (s, 6H).‘3C{’H} NMR (CDC13, 100 MHz): 3 145,8, 140.5, 129.5, 129.3, 128.2, 112.1, 59.1, 46.2, 30.8. HRMS (El) mlz calcd forC12H7NS: 207.1082; found: 207.1078. 62 ‘H NMR (CDC13,300 MHz) 24a ChmiooI Shift (ppm) ‘3c NMR (CDC13,100 MHz) LJ 24a — 192 184 176 168 180 102 144 136 128 120 112 104 96 88 80 72 64 86 48 40 32 24 16 8 Chemical Shift (ppm) 63 H3CO + H3CO-Q-- 3 O:3)2 1.1 equivoerS 24h,rt,80% OCH3 23a 1,2-Bis(1-(4-methoxyphenyl)vinylthio)hexane (34a): Yellow oil, 80% yield. Column chromatography conditions: 20:1 hexanes:EtOAc. ‘H NMR (C6D, 400 MHz): 6 7.60 — 7.56 (m, 4H), 6.76 — 6.73 (m, 4H), 5.41 (s, 2H), 5.13 (s, 2H), 3.30 (s, 6H), 2.50 (t, 4H, J 7.3 Hz), 1.45 (quin, 4H, J = 7.3 Hz), 1.13 (quin, 4H, J = 3.7 Hz).‘3C{’H} NMR (C6D, 100 MHz): 6 160.8, 145.9, 133.1, 129.1, 114.5, 109.6, 55.2, 32.6, 29.1, 29.0. HRMS (El) mlz calcd forC24H30S02: 414.1686; found: 414.1687. Anal. calcd for C24H30S02: C, 69.52; H, 7.29; found: C, 69.20; H, 7.31. 64 ‘H NIVIR (C6D,400 MHz) 28a OCH ChmiI Shift (ppm) 13, i- i KTT \ L- P4.LVLL I VU IVLf1Z) H3CO XySsIQ 28a OCH3 _ .. __ 192 184 176 168 160 162 144 136 129 120 112 104 96 88 80 72 64 56 48 40 32 24 16 8 ChmmI Shift (ppm) 65 Synthesis of complex II. In glove box, a solution of Tp*Rh(PPh3)2(93 mg, 0.1 mmol) in toluene (1 mL) were combined in the glove box in a 5 mL vial equipped with a screw cap and a magnetic stir bar. 2-pyridylacetylene (0.1 mL, 1.0 mmol) was added by syringe to the solution. The mixture was stirred for 2 h at room temperature, followed by layering with 2 mL hexanes. After 2 days, brown crystals formed. The solution was decanted, and the crystals were washed with 2 x 1 mL of hexanes. The product was dried under reduced pressure to give 50 mg (65 %) of an brown crystalline solid. ‘H NMR (CD2C1, 400 MHz) at 25 °C: 8 8.19 (d, lH, J 3.9 Hz) 7.60 (m, 6H),7.42 — 7.33 (m, 4H), 7.24 — 7.20 (m, 6H), 7.70 — 6.90 (m, 2H), 5.71 (d, 2H, J= 8.8 Hz), 5.17 (s, 1H), 2.72 (s, 3H), 2.50 (s, 3H), 2.30 (s, 3H), 2.25 (s, 3H), 1.44 (s, 3H), 1.37 (s, 3H), 6-14.68 (q, lH, JRII-H= 20.5 HZ,JP..H 17.6 Hz), B-H not observed.‘3C{’H} NMR (CD2C1,100 MHz): 6 154.5, 150.8, 149.8, 147.8, 145.5, 144.5, 135.9, 135.8, 135.6, 133.8, 133.4, 130.5, 128.2, 128.1, 126.1, 119.7, 107.5, 106.3, 106.1, 16.5, 13.2, 12.9, 12.1. 31P{’H} NMR (CD2C1, 121 MHz): 6 37.69 (JR1,p 130.8 Hz). HRMS (El) miz calcd forC40H2BN7PRh: 765.2387; found: 765.2389. X-Ray crystal structure of complex II: Measurement for complexes II was made on a Bruker X8 APEX II diffractometer with graphite monochromated Mo-Ka radiation. Data were collected in a series of 0 and co scans and subsequently processed with the Bruker SAINT24 software package. Data were corrected for absorption effects using the multiscan technique (SADABS).25 Data were corrected for by Lorentz and polarization effects. The structure was solved using direct methods26 and refined using SHELXTL.27 For complexe II all non-hydrogen atoms were refined anisotropically, whereas all hydrogen atoms were placed in calculated positions and not refined, except for B-H 66 hydrogen which was located in difference maps and refined isotropically. The material crystallizes with both toluene and hexane in the lattice. In this ease, there was a 1:2 mixture of toluene and hexane occupying the same space in the asymmetric unit. Mild restraints were employed to maintain reasonable geometries for both solvent molecules. Full details for complex II are presented in the Appendix. 67 I 6 5 4 3 2 I 0 -l -2 -3 -4 -5 -6 -7 -8 -9 -10 -11 -12 -13 -14 .15 -16 Chen1 ShWt (ppm) .ljj Complex II p •1 Mflrr1II$I, 192 184 176 168 160 152 144 136 128 120 112 104 96 88 80 72 84 56 48 40 32 24 16 8 CmniI Shtppm) ‘H NMR (CD2C1,400 MHz) Complex II 9 9 7 ‘3c NMR (CD2I,100 MHz) I [. - 68 Chapter 3 — Summary, Conclusons and Future Work 3.1 Summary and Conclusions The goal of this thesis project was to explore the substrate scope and limitations of alkyne hydrothiolation using Tp*Rh(PPh3)2as the catalyst. Tp*Rh(PPh3)2was found to be effective for a variety of thiols and alkynes, including both terminal and internal alkynes. Most of the reactions gave good-to-excellent yields, and the branched isomer was favored in most cases. Electronic substitution of substituted phenyl acetylenes had little influence on regioselectivity, but had a great impact on the reaction efficiency and yields. Aliphatic alkynes need longer reaction time to complete reaction compared to aryl alkynes. A wide range of functional groups were tolerated, including halides, amines, nitriles, amines, ethers, esters and silanes. Alkoxy groups with the ability to coordinate with rhodium slowed down the catalytic turnover and lower the yield. Strongly coordinating groups, such as pyridine, totally precluded catalysis. The regioselectivity of the catalyst was reversed when electronically activated alkynes, i.e., those that undergo Michael addition, were used. Hydrothiolation using internal alkynes was much more difficult and needed longer reaction time and higher reaction temperature for completion. 69 3.2 Future Work Further attention is warranted in several areas. In a few reactions, some byproducts were formed (about 5-10%). Although efforts to date have been unsuccessful in unequivocally determining the identity of the byproducts, larger scale reactions could provide sufficient material for isolation and characterization. Moreover, the product identity could provide some mechanistic clues. On the other hand, a detailed mechanistic picture could point out how to minimize the byproduct and also give more information about the scope and limitation. Such mechanistic work is currently underway.’31’ We have demonstrated that the products of the hydrothiolation using n-propanethiol are suitable for Kumada cross-coupling to generate 1,1-disubstituted olefins. Other functionalization of 1,1 -disubstituted vinyl sulfide could also be studied, such as Diels Alder reactions. In addition, hydrothiolation could be used as a key step in the synthesis of some sulfur containing natural products and drug molecules28,such as Emtricitabine, Eletriptan, and Ertapenem (see Figure 3.1). 0 NH H OH HOQ N OH H Figure 3.1. Emtricitabine, Eletriptan, and Ertapenem The Tp* ligand has shown unique properties in rhodium catalyzed alkyne hydrothiolation. It would be interesting to synthesize other metal complexes with this ligand. These new complexes may have different reactivity in hydrothiolation, as well as 70 other reactions, such as asymmetric hydrogenation, cyclotrimerization and Diels-Alder reactions, In addition, other bidentate or tridentate ligands can also be used to form new rhodium complexes. Those new ligands may provide new selectivities in hydrothiolations. After having demonstrated the use of Tp*Rh(PPh3)2in S-H and P-H bond activation reactions, activation of H-X bonds (such as X = 0) could be paid more attention. For example, the intermolecular alkyne hydroalkoxylation using rhodium complex could be an interesting research topic. 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(b) Wenkert, E.; Shepard, M. E.; Mcphail, A. T. I Chem. Soc. Chem. Commun. 1986, 13, 1390-1391. (c) Okamura, H.; Miura, M.; Takei, H. Tetrahedron Lett. 1979, 1, 43-46. (21) (a) Amer, I.; Bernstein, T.; Eisen, M.; Blum, 3.; Vollhardt, K.P.C. J. Mo!. Catal. 1990, 60, 313-321. (b) Agenet, N.; Gandon, V.; Vollhardt, K.P.C.; Malacria, M.; Aubert, C. J. Am. Chem. Soc. 2007, 129, 8860-887 1. (22) Pangborn, A. B.; Giardello, M. A.; Grubbs, R. H.; Rosen, R. K.; Timmers, F. 3. Organometallics 1996, 15, 1518-1520. (23) (a) Connelly, N. G.; Emslie, D. J. H.; Geiger, W. E.; Hayward, 0. D.; Linehan, E. B.; Orpen, A. G.; Quayle, M. J.; Rieger, P. H. I Chem. Soc., Dalton Trans 2001, 75 670- 683. (b) CIrcu, V.; Fernandes, M. A.; Canton, L. Inorg. Chem. 2002, 41, 3859- 3865. (24) Bruker SAINT software package, version 7.03A; Bruker AXS Inc.: Madison, WI, 1997-2003. (25) Bruker SAINT software package, Version 2.10; Bruker AXS Inc.: Madison, WI, 2003. (26) Altomare, A.; Burla, M. C.; Camalli, M.; Cascarano, G. L.; Giacovazzo, C.; Guagliardi, A.; Molitemi, A. G. G.; Polidori, G.; Spagna, R. I Appi. Cryst. 1999, 32, 115-119. (27) Bruker SAINT software package, Version 5.1; Bruker AXS Inc.: Madison, WI, 1997. (28)Fernández, F.; Khiar, N. Chem. Rev. 2003, 103, 365 1-3705. 76 Appendix: X-ray Crystallographic Data for Complex II A. Crystal Data Empirical Formula C40H2BN7PRh Formula Weight 765.50 Crystal Color, Habit yellow, prism Crystal Dimensions 0.26 X 0.44 X 0.50 mm Crystal System orthrhombic Lattice Type primitive Lattice Parameters a = 15.85 1(2) A ci. = 90.0 b= 19.184(3)A =9O.O c=23.951(4)A y=9O.O V = 4667.9(8) A3 Space Group P bca (#6 1) Z value 8 Dcalc 1.396g/cm F000 3168.00 .i(MoKa) 5.53cm’ B. Intensity Measurements Diffractometer Bruker X8 APEX II Radiation MoKc ( = 0.7 1073 A) graphite monochromated Data Images 1071 exposures @ 5.0 seconds Detector Position 36.00 mm 2Omax 56.0° No. of Reflections Measured Total: 67640 Unique: 8786 (R1 = 0.025) Corrections Absorption (T1= 0.803, Tmax= 0.866); Lorentz-polarization C. Structure Solution and Refmement Structure Solution Direct Methods (S1R97) Refmement Full-matrix least-squares on F2 Function Minimized w (Fo2 — Fe2) Least Squares Weights w=1/(a( o)+(0.0252P) + 6.3229P) Anomalous Dispersion All non-hydrogen atoms No. Observations (I>0.OOa(1)) 8786 No. Variables 465 Reflection/Parameter Ratio 18.89 77 Residuals (refined on F2, all data): Ri; wR2 0.034; 0.066 Goodness of Fit Indicator 1.08 No. Observations (I>2.OOa(I)) 8528 Residuals (refined on F): RI; wR2 0.024; 0.058 Max ShiftlError in Final Cycle 0.00 Maximum peak in Final Diff. Map 0.37 e/A3 Minimum peak in Final Diff. Map -0.45 e/A3 78 Table 1. Atomic Coordinates (x 1O) and Equivalent Isotropic Displacement Parameters (A x 1O) Atom X Y Z U(eq) C(1) 3595(1) 1859(1) 6238(1) 26(1) C(2) 3929(1) 1913(1) 6819(1) 21(1) C(3) 3465(1) 1887(1) 7317(1) 25(1) C(4) 4042(1) 1909(1) 7743(1) 23(1) C(5) 3909(1) 1919(1) 8362(1) 32(1) C(6) 7592(1) 3523(1) 6858(1) 26(1) C(7) 7058(1) 3235(1) 7313(1) 22(1) C(8) 7088(1) 3391(1) 7883(1) 28(1) C(9) 6529(1) 2945(1) 8142(1) 26(1) C(10) 6290(1) 2875(1) 8746(1) 40(1) C(11) 7217(1) 661(1) 6221(1) 29(1) C(12) 6883(1) 779(1) 6797(1) 23(1) C(13) 7009(1) 381(1) 7278(1) 28(1) C(14) 6576(1) 707(1) 7700(1) 24(1) C(15) 6504(1) 504(1) 8301(1) 35(1) C(16) 5451(1) 3915(1) 6643(1) 20(1) C(17) 4991(1) 3753(1) 7125(1) 23(1) C(18) 4926(1) 4232(1) 7557(1) 30(1) C(19) 5326(1) 4875(1) 7518(1) 33(1) C(20) 5784(1) 5037(1) 7047(1) 31(1) C(21) 5845(1) 4562(1) 6608(1) 26(1) C(22) 6200(1) 3632(1) 5559(1) 21(1) C(23) 5907(1) 4228(1) 5282(1) 30(1) C(24) 6402(1) 4560(1) 4888(1) 36(1) C(25) 7189(1) 4299(1) 4758(1) 34(1) C(26) 7481(1) 3703(1) 5016(1) 33(1) C(27) 6985(1) 3370(1) 5414(1) 26(1) C(28) 4519(1) 3282(1) 5750(1) 20(1) C(29) 3845(1) 3669(1) 5962(1) 24(1) C(30) 3094(1) 371 5(1) 5664(1) 29(1) C(31) 3002(1) 3375(1) 5157(1) 32(1) C(32) 3671(1) 2993(1) 4944(1) 30(1) C(33) 4428(1) 2948(1) 5234(1) 25(1) C(34) 5683(1) 1740(1) 5812(1) 19(1) C(35) 5547(1) 1443(1) 5374(1) 23(1) C(36) 5323(1) 1054(1) 4883(1) 22(1) C(37) 4368(1) 825(1) 4190(1) 37(1) C(38) 4811(1) 261(1) 3996(1) 35(1) C(39) 5562(1) 98(1) 4256(1) 33(1) C(40) 5827(1) 500(1) 4703(1) 27(1) N(1) 4756(1) 1961(1) 6936(1) 19(1) 79 N(2) 4819(1) 1941(1) 7510(1) 20(1) N(3) 6490(1) 2726(1) 7228(1) 19(1) N(4) 6183(1) 2542(1) 7741(1) 21(1) N(5) 6393(1) 1324(1) 6923(1) 19(1) N(6) 6199(1) 1281(1) 7483(1) 20(1) N(7) 4598(1) 1226(1) 4623(1) 31(1) Rh(1) 5973(1) 2226(1) 6507(1) 15(1) B(1) 5683(1) 1856(1) 7788(1) 21(1) P(i) 5545(1) 3240(1) 6105(1) 17(1) 80 Table 2. Bond Lengths (A) Atoms Length (A) Atoms Length (A) C(1)-C(2) 1.492(2) C(21)-H(21) 0.95 C(1)-H(1A) 0.98 C(22)-C(27) 1.385(2) C(1 )-H(1 B) 0.98 C(22)-C(23) 1.401(2) C(1)-H(1 C) 0.98 C(22)-P(1) 1.8334(17) C(2)-N(1) 1.343(2) C(23)-C(24) 1.382(3) C(2)-C(3) 1.401(2) C(23)-H(23) 0.95 C(3)-C(4) 1.371(3) C(24)-C(25) 1.380(3) C(3)-H(3) 0.95 C(24)-H(24) 0.95 C(4)-N(2) 1.354(2) C(25)-C(26) 1.378(3) C(4)-C(5) 1.497(3) C(25)-H(25) 0.95 C(5)-H(5A) 0.98 C(26)-C(27) 1.393(3) C(5)-H(5B) 0.98 C(26)-H(26) 0.95 C(5)-H(5C) 0.98 C(27)-H(27) 0.95 C(6)-C(7) 1.488(2) C(28)-C(29) 1.396(2) C(6)-H(6A) 0.98 C(28)-C(33) 1.398(2) C(6)-H(6B) 0.98 C(28)-P( 1) 1.8374(17) C(6)-H(6C) 0.98 C(29)-C(30) 1.392(2) C(7)-N(3) 1.343(2) C(29)-H(29) 0.95 C(7)-C(8) 1.399(3) C(30)-C(3 1) 1.386(3) C(8)-C(9) 1.379(3) C(30)-H(30) 0.95 C(8)-H(8) 0.95 C(31)-C(32) 1.387(3) C(9)-N(4) 1.351(2) C(3 1)-H(3 1) 0.95 C(9)-C(1 0) 1.501(3) C(32)-C(33) 1.389(3) C(10)-H(1OA) 0.98 C(32)-H(32) 0.95 C(1 0)-H(1 OB) 0.98 C(33)-H(33) 0.95 C(1 0)-H(1 OC) 0.98 C(34)-C(35) 1.212(2) C(1 1)-C(12) 1.494(3) C(34)-Rh(1) 1.9627(17) C( 11 )-H(1 1A) 0.98 C(35)-C(36) 1.437(2) C(1 1)-H(1 1B) 0.98 C(36)-N(7) 1.348(2) C(1 1)-H(1 1C) 0.98 C(36)-C(40) 1.398(2) C( 1 2)-N(5) 1.338(2) C(37)-N(7) 1.342(3) C(12)-C(13) 1.397(2) C(37)-C(38) 1.371(3) C(1 3)-C(1 4) 1.372(3) C(37)-H(37) 0.95 C(1 3)-H(1 3) 0.95 C(38)-C(39) 1.380(3) C(14)-N(6) 1.355(2) C(38)-H(3 8) 0.95 C(1 4)-C(1 5) 1.497(3) C(39)-C(40) 1.383(3) C(1 5)-H(1 5A) 0.98 C(3 9)-H(39) 0.95 C(15)-H(15B) 0.98 C(40)-H(40) 0.95 C(1 5)-H(1 5C) 0.98 N(1)-N(2) 1.3773(19) C(1 6)-C(21) 1.392(2) N(1 )-Rh(1) 2.2448(14) C(16)-C(17) 1.399(2) N(2)-B(1) 1.531(2) C(16)-P(1) 1.8330(17) N(3)-N(4) 1.368(2) 81 C(17)-C(18) 1.388(2) N(3)-Rh(1) 2.1386(14) C(1 7)-H(1 7) 0.95 N(4)-B(1) 1.541(2) C(18)-C(19) 1.391(3) N(5).N(6) 1.379(2) C(18)-H(18) 0.95 N(5)-Rh(1) 2.1037(14) C(1 9)-C(20) 1.375(3) N(6)-B(1) 1.555(2) C(1 9)-H(1 9) 0.95 Rh(1 )-P(1) 2.2732(5) C(20)-C(21) 1.395(3) Rh(1)-H(1) 1.46(2) C(20)-H(20) 0.95 B(1)-H(2) 1.068(19) 82 Table 3. Bond Angles fl Atoms Angle (°) Atoms Angle (°) C(2)-C(1)-H(1A) 109.5 C(26)-C(25)-C(24) 120.18(18) C(2)-C(1)-H(1B) 109.5 C(26)-C(25)-H(25) 119.9 H(1A)-C(1)-H(1B) 109.5 C(24)-C(25)-H(25) 119.9 C(2)-C(1)-H(1C) 109.5 C(25>C(26)eC(27) 119.88(18) H(1A)-C(1)-H(1C) 109.5 C(25)-C(26)-H(26) 120.1 H(1B)-C(1)-H(1C) 109.5 C(27)-C(26)-H(26) 120.1 N(1)-C(2)-C(3) 109.71(15) C(22)-C(27)-C(26) 120.72(17) N(1)-C(2)-C(1) 123.06(16) C(22)-C(27)-H(27) 119.6. C(3)-C(2)-C(1) 127.16(15) C(26)-C(27)-H(27) 119.6 C(4)-C(3)-C(2) 106.39(15) C(29)-C(28)-C(33) 119.08(16) C(4)-C(3)-H(3) 126.8 C(29)-C(28)-P(1) 122.12(13) C(2)-C(3)-H(3) 126.8 C(33)-C(28)-P(1) 118.70(13) N(2)-C(4)-C(3) 107.48(15) C(30)-C(29)-C(28) 120.09(17) N(2)-C(4)-C(5) 122A6(16) C(30)-C(29)-H(29) 120 C(3)-C(4)-C(5) 130.04(16) C(28)-C(29)-H(29) 120 C(4)-C(5)-H(5A) 109.5 C(31)-C(30)-C(29) 120.64(18) C(4)-C(5)-H(5B) 109.5 C(31)-C(30)-H(30) 119.7 H(5A)-C(5)-H(5B) 109.5 C(29)-C(30)-H(30) 119.7 C(4)-C(5)-H(5C) 109.5 C(30)-C(31)-C(32) 119.37(17) H(5A)-C(5)-H(5C) 109.5 C(30)-C(31)-H(31) 1203 H(5B)-C(5)-H(SC) 109.5 C(32)-C(31)-H(31) 120.3 C(7)-C(6)-H(6A) 109.5 C(31)-C(32)-C(33) 120.58(1 8) C(7)-C(6)-H(6B) 109.5 C(31)-C(32)-H(32) 119.7 H(6A)-C(6)-H(6B) 109.5 C(33)-C(32)-H(32) 119.7 C(7)-C(6)-H(6C) 109.5 C(32)-C(33)-C(28) 12021(17) H(6A)-C(6)-H(6C) 109.5 C(32)-C(33)-H(33) 119.9 H(6B)-C(6)-H(6C) 109.5 C(28)-C(33)-H(33) 119.9 N(3)-C(7)-C(8) 109.13(16) C(35)-C(34)-Rh(1) 176.59(15) N(3)-C(7)-C(6) 122.66(15) C(34)-C(35)-C(36) 174.47(18) C(8)-C(7)-C(6) 128.07(16) N(7)-C(36)-C(40) 121.96(16) C(9)-C(8)-C(7) 106.49(15) N(7)-C(36)-C(35) 117.47(16) C(9)-C(8)-H(8) 126.8 C(40)-C(36)-C(35) 120.51(16) C(7)-C(8)-H(8) 126.8 N(7)-C(37)-C(38) 125.08(19) N(4)-C(9)-C(8) 107.22(16) N(7)-C(37)-H(37) 1173 N(4)-C(9)-C(10) 122.18(17) C(38)-C(37)-H(37) 117.5 C(8)-C(9)-C(10) 130.60(17) C(37)-C(38)-C(39) 117.89(18) C(9)eC(10)H(10A) 109.5 C(37>C(38>H(38) 121.1 C(9)-c(10)-H(1OB) 109.5 C(39)-C(38)-H(38) 121.1 H(1)4D()10) 109.5 C(38)-C(39)-C(40) 118.96(19) C(9)-C(10)-H(1OC) 109.5 C(38)-C(39)-H(39) 120.5 H(1>COO> 109.5 C(40)-C(39)-H(39) 120.5 83 H( 1 OB)-C( 10)- 109.5 C(39)-C(40)-C(36) 119.37(18)H(1OC) C(1 2)-C(1 1)- 109.5 C(39)-C(40)-H(40) 120.3H(1 IA) C(1 2)-C(1 1)- 109.5 C(36)-C(40)-H(40) 120.3H(11B) H(1 1A)-C(1 1)- 109.5 C(2)-N(1)-N(2) 106.12(13)H(11B) C(12)—C(1 1)— 109.5 C(2)-N(1)-Rh(1) 139.34(12)H(11C) H(1 1A)—C(1 1)— 109.5 N(2)-N(1)-Rh(1) 113.58(10)H(1IC) H(11B)-C(11)- 109.5 C(4)-N(2)-N(1) 110.25(14)H(11C) N(5)-C(12)-C(13) 108.94(16) C(4)-N(2)-B(1) 128.97(15) N(5)-C(12)-C(1 1) 122.16(16) N(1)-N(2)-B(1) 120.13(13) C(13)-C(12)-C(1 1) 128.89(16) C(7)-N(3)-N(4) 106.80(13) C(14)-C( 1 3)-C(12) 106.61(15) C(7)-N(3)-Rh(1) 134.92(12) C(14)-C(13)-H(13) 126.7 N(4)-N(3)-Rh(1) 118.21(10) C(1 2)-C(1 3)-H(1 3) 126.7 C(9)-N(4)-N(3) 110.32(14) N(6)-C(14)-C(1 3) 108.03(16) C(9)-N(4)-B(1) 130.27(15) N(6)-C(14)-C(15) 123.13(17) N(3)-N(4)-B(1) 117.97(13) C(13)-C(14)-C(1 5) 128.84(17) C(12)-N(5)-N(6) 107.51(13) C(14)-C(15)- 109.5 C(12)-N(5)-Rh(1) 136.08(12)H(15A) C(1 4)-C(1 5)- 109.5 N(6)-N(5)-Rh(1) 116.10(10)H(15B) H(1 5A)-C(1 5)- 109.5 C(14)-N(6)-N(5) 108.90(14)H(15B) C(14)-C(1 5)- 109.5 C(14)-N(6)-B(1) 128.90(15)H(15C) H(1 5A)-C(1 5)- 109.5 N(5)-N(6)-B(1) 122.05(13)H(15C) H(1 5B)-C(1 5)- 109.5 C(37)-N(7)-C(36) 116.69(17)H(15C) C(2 1 )-C( 1 6)-C(1 7) 118.74(16) C(34)-Rh(1 )-N(5) 94.85(6) C(2 1 )-C(1 6)-P(1) 123.47(13) C(34)-Rh( 1 )-N(3) 171.02(6) C(1 7)-C(1 6)-P( 1) 117.72(12) N(5)-Rh(1 )-N(3) 82.29(5) C(1 8)-C(1 7)-C(1 6) 120.46(16) C(34)-Rh(1 )-N(1) 94.55(6) C(1 8)-C(1 7)-H(1 7) 119.8 N(5)-Rh(1 )-N(1) 82.46(5) C( J. 6)-C( 1 7)-H( 17) 119.8 N(3)-Rh(1 )-N(1) 93.52(5) C(1 7)-C(1 8)-C(1 9) 120.20(18) C(34)-Rh(1 )-P(1) 88.72(5) C(1 7)-C(1 8)-H(1 8) 119.9 N(5)-Rh( 1 )-P(1) 176.42(4) C(19)-C(1 8)-H(1 8) 119.9 N(3)-Rh(1)-P(1) 94.14(4) C(20)-C(1 9)-C(1 8) 119.73(17) N(1)-Rh(1)-P(1) 97.51(4) C(20)-C( 1 9)-H(1 9) 120.1 C(34)-Rh( 1 )-H(1) 83 .8(9) 84 C(1 8)-C(i 9)-H(1 9) 120.1 N(5)-Rh(1)-H(1) 92.1(8) C(1 9)-C(20)-C(2 1) 120.45(17) N(3)-Rh(1 )-H(1) 87.8(9) C(1 9)C(20)-H(20) 119.8 N(1)-Rh(1)-H(1) 174.1(8) C(2J )-C(20)-H(20) 119.8 P(1)-Rh(1)-H(1) 88.1(8) C(1 6)-C(2 1 )-C(20) 120.40(17) N(2)-B( 1 )-N(4) 109.69(14) C(16)-C(21)H(21) 119.8 N(2)-B(1)-N(6) 110.01(14) C(20)-C(2 1)-H(2 1) 1 19.8 N(4)-B(1 )..N(6) 107.54(14) C(27)-C(22)-C(23) 118.48(16) N(2)-B(1 )-H(2) 111.2(10) C(27)-C(22)-P(1) 122.53(13) N(4)-B(1)-H(2) 109.8(10) C(23)-C(22)-P(1) 118.97(13) N(6)-B(1)-H(2) 108.5(10) C(24)-C(23)-C(22) 120.63(18) C( 1 6)-P(1 )-C(22) 104.94(8) C(24)-C(23)-H(23) 119.7 C( 1 6)-P( 1 )-C(28) 102.88(8) C(22)-C(23)-H(23) 119.7 C(22)-P(1)-C(28) 98.75(8) C(25)-C(24)-C(23) 120.06(19) C(1 6)-P(1 )-Rh(1) 109.33(6) C(25)-C(24)-H(24) 120 C(22)-P(1)-Rh(1) 118.96(6) C(23)-C(24)-H(24) 120 C(28)-P(1 )-Rh( 1) 119.92(5) 85 Table 4. Anisotropic Displacement Parameters (A x 1O) Atom U11 U22 U33 U23 U’3 U’2 C(1) 21(1) 27(1) 29(1) 2(1) -4(1) C(2) 18(1) 16(1) 28(1) 1(1) -2(1) -2(1) C(3) 18(1) 24(1) 32(1) 2(1) 3(1) -1(1) C(4) 22(1) 19(1) 27(1) 1(1) 5(1) C(5) 30(1) 37(1) 27(1) 0(1) 9(1) 1(1) C(6) 22(1) 24(1) 33(1) -2(1) -1(1) 5(1) C(7) 19(1) 20(1) 28(1) -4(1) -4(1) 1(1) C(8) 26(1) 30(1) 29(1) -10(1) -4(1) -5(1) C(9) 24(1) 31(1) 24(1) •.8(1) -5(1) -1(1) C(10) 40(1) 54(1) 26(1) -13(1) 1(1) -11(1) C(11) 26(1) 27(1) 32(1) -4(1) 0(1) 6(1) C(12) 19(1) 19(1) 30(1) -2(1) -3(1) 0(1) C(13) 25(1) 19(1) 38(1) 3(1) —5(1) 3(1) C(14) 22(1) 21(1) 30(1) 7(1) -6(1) -2(1) C(15) 39(1) 34(1) 33(1) 13(1) -5(1) 3(1) C(16) 17(1) 19(1) 24(1) -1(1) 0(1) 2(1) C(17) 24(1) 20(1) 25(1) 0(1) 1(1) -1(1) C(18) 32(1) 32(1) 25(1) -6(1) 4(1) 1(1) C(19) 37(1) 28(1) 33(1) -12(1) -1(1) 3(1) C(20) 31(1) 20(1) 42(1) -6(1) -1(1) -3(1) C(21) 24(1) 21(1) 32(1) 0(1) 3(1) -2(1) C(22) 21(1) 22(1) 20(1) 2(1) 2(1) -3(1) C(23) 24(1) 31(1) 35(1) 11(1) 7(1) 3(1) C(24) 35(1) 35(1) 38(1) 16(1) 4(1) -3(1) C(25) 32(1) 43(1) 26(1) 7(1) 7(1) -11(1) C(26) 24(1) 47(1) 29(1) 3(1) 8(1) 0(1) C(27) 25(1) 31(1) 23(1) 3(1) 3(1) 2(1) C(28) 18(1) 19(1) 22(1) 5(1) -1(1) -1(1) C(29) 21(1) 22(1) 29(1) 2(1) 0(1) -1(1) C(30) 20(1) 28(1) 39(1) 5(1) -1(1) 3(1) C(31) 24(1) 38(1) 35(1) 12(1) -9(1) -2(1) C(32) 31(1) 35(1) 24(1) 3(1) -6(1) -4(1) C(33) 25(1) 27(1) 23(1) 2(1) 0(1) 0(1) C(34) 18(1) 18(1) 21(1) 1(1) -1(1) 0(1) C(35) 23(1) 22(1) 25(1) -2(1) -1(1) 0(1) C(36) 25(1) 23(1) 19(1) 0(1) 1(1) -4(1) C(37) 37(1) 45(1) 28(1) -1(1) -11(1) -5(1) C(38) 47(1) 38(1) 20(1) -6(1) 0(1) -15(1) C(39) 42(1) 29(1) 29(1) -8(1) 8(1) -4(1) C(40) 28(1) 27(1) 24(1) -3(1) 1(1) -1(1) N(1) 18(1) 20(1) 19(1) 1(1) —1(1) —1(1) N(2) 20(1) 20(1) 19(1) 1(1) 1(1) -1(1) 86 N(3) 18(1) 18(1) 20(1) -1(1) -2(1) •1(i) N(4) 21(1) 23(1) 19(1) -2(1) .2(1) 1(1) N(5) 19(1) 19(1) 20(1) 0(1) —1(1) 0(1) N(6) 19(1) 21(1) 21(1) 3(1) -2(1) -1(1) N(7) 31(1) 34(1) 29(1) -4(1) -7(1) 2(1) Rh(1) 14(1) 14(1) 16(1) —1(1) .1(1) —1(1) B(1) 21(1) 23(1) 20(1) 1(1) -2(1) 0(1) P(1) 16(1) 16(1) 18(1) 0(1) 2(1) 0(1) 87 Table 5. Torsional Angles (°) Atoms Angle Atoms Angle N( 1 )-C(2)-C(3)-C(4) .1.04(19) Rh(l )-N(5)-N(6)-C(14) - 174.44(11) C(1)-C(2)-C(3)-C(4) 175.87(16) C(1 2)-N(5)-N(6)-B(1) 176.02(14) C(2)-C(3)-C(4)-N(2) -0.43(19) Rh(1 )-N(5)-N(6)-B(1) 1.37(18) C(2)-C(3)-C(4)-C(5) 177.82(18) C(38)-C(37)-N(7). C(36) -0.1(3) N(3)-C(7)-C(8)-C(9) 1.3(2) C(40)-C(36)-N(7)-C(37) 2.0(3) C(6)-C(7)-C(8)-C(9) -174.33(17) C(3 5)-C(36)-N(7)-C(3 7) -175.23(17) C(7)-C(8)-C(9)-N(4) 0.0(2) C(3 5)-C(34)-Rh(1)-N(S) -85(2) C(7)-C(8)-C(9)-C( 10) -179.5(2) C(3 S)-C(34)-Rh( 1 )-N(3) -14(3) N(S)-C( 1 2)-C( 1 3)-C( 14) 0.0(2) C(3 5)-C(34)-Rh( 1 )-N(1) -168(2) C(1 1 )-C(1 2)-C(1 3)-C(1 4) 179.58(17) C(3 5)-C(34)-Rh(1 )-P(1) 95(2) C(1 2)-C( 1 3)-C(1 4)-N(6) 0.1(2) C(1 2)-N(5)-Rh( 1 )-C(34) 45.16(17) C(1 2)-C(1 3)-C(14)-C(1 5) -179.57(18) N(6)-N(5)-Rh(1 )-C(34) -142.20(11) C(2 1)-C(1 6)-C(1 7)-C(1 8) 0.3(3) C(1 2)-N(5)-Rh(1 )-N(3) - 126.27(17) P(1 )-C(1 6)-C(1 7)-C(1 8) 177.40(14) N(6)-N(S)-Rh(1 )-N(3) 46.37(11) C(1 6)-C(1 7)-C(I 8)-C(1 9) -0.7(3) C(1 2)-N(5)-Rh(1 )-N(1) 139.12(17) C( 1 7)-C(i 8)-C( 1 9)-C(20) 0.4(3) N(6)-N(5)-Rh(1 )-N(1) -48.24(11) C(1 8)-C( 1 9)-C(20)-C(2 1) 0.3(3) C( 1 2)-N(S)-Rh(1 )-P(1) -131.1(6) C( 1 7)-C(1 6)-C(2 1 )-C(20) 0.4(3) N(6)-N(5)-Rh( 1 )-P( 1) 41.6(7) P(1)-C(1 6)-C(2 1 )-C(20) -176.S2(14) C(7)-N(3)-Rh(1)-C(34) 53.6(4) C(1 9)-C(20)-C(2 1 )-C( 16) -0.7(3) N(4)-N(3)-Rh( 1 )-C(34) -130.0(4) C(27)-C(22)-C(23)-C(24) -2.1(3) C(7)-N(3)-Rh( 1 )-N(5) 125.56(16) P( 1 )-C(22)-C(23)-C(24) 176.69(16) N(4)-N(3)-Rh( 1 )-N(5) -58.09(11) C(22)-C(23)-C(24)-C(25) 0.7(3) C(7)-N(3)-Rh( 1 )-N(1) -152.55(16) C(23)-C(24)-C(25)-C(26) 0.8(3) N(4)-N(3)-Rh( 1 )-N(1) 23.81(12) C(24)-C(25)-C(26)-C(27) -1.0(3) C(7)-N(3)-Rh( 1 )-P( 1) -54.75(16) C(23)-C(22)-C(27)-C(26) 1.9(3) N(4)-N(3)-Rh(1 )-P(1) 121.61(11) P(1)-C(22)-C(27)-C(26) -176.85(15) C(2)-N(1 )-Rh(1)-C(34) -39.85(18) C(25)-C(26)-C(27)-C(22) -0.3(3) N(2)-N( 1 )-Rh( 1 )-C(34) 153.51(11) C(3 3)-C(28)-C(29)-C(30) 0.4(2) C(2)-N( 1 )-Rh(1 )-N(5) -134.16(18) P(1 )-C(28)-C(29)-C(30) 176.73(13) N(2)-N(1)-Rh(1 )-N(S) 59.20(11) C(28)-C(29)-C(3 0)-C(3 1) 0.5(3) C(2)-N( 1 )-Rh( 1 )-N(3) 144.10(17) C(29)-C(3 0)-C(3 1 )-C(32) -0.8(3) N(2)-N( 1 )-Rh( 1 )-N(3) -22.54(11) C(30)-C(3 1 )-C(32)-C(33) 0.1(3) C(2)-N(1 )-Rh( 1 )-P( 1) 49.46(17) C(3 1)-C(32)-C(33)-C(28) 0.8(3) N(2)-N(1)-Rh(1 )-P(1) -117.18(10) C(29)-C(28)-C(33)-C(32) -1.0(3) C(4)-N(2)-B( I )-N(4) -116.39(18) P(1 )-C(28)-C(33)-C(32) -177.0(14) N(1 )-N(2)-B(1 )-N(4) 73.77(18) Rh(1 )-C(34)-C(35)-C(36) 149.7(18) C(4)-N(2)-B(1 )-N(6) 125.50(17) C(34)-C(3 5)-C(3 6)-N(7) 75(2) N(1 )-N(2)-B(1 )-N(6) -44.33(19) C(34)-C(3 5)-C(36)-C(40) -103(2) C(9)-N(4)-B( 1 )-N(2) 123.19(19) N(7)-C(3 7)-C(3 8)-C(3 9) -1.4(3) N(3)-N(4)-B( 1 )-N(2) -71.92(18) C(3 7)-C(3 8)-C(3 9)-C(40) 0.9(3) C(9)-N(4)-B( 1 )-N(6) -117.19(19) C(3 8)-C(3 9)-C(40)-C(36) 0.8(3) N(3)-N(4)-B( 1 )-N(6) 47.71(19) 88 N(7)-C(3 6)-C(40)-C(39) -2.4(3) C( 1 4)-N(6)-B( 1 )-N(2) -126.28(17) C(3 5)-C(36)-C(40)-C(3 9) 174.74(17) N(5)-N(6)-B( 1 )-N(2) 58.82(19) C(3>C(2)-N( 1 )-N(2) 2.05(18) C( 1 4)-N(6)-B( 1 )-N(4) 114.30(18) C( I )-C(2)-N( 1 )-N(2) - 175.01(15) N(5)-N(6)-B(1 )-N(4) -60.59(19) C(3)-C(2)-N(1)-Rh(1) -165.22(13) C(2 1)-C(1 6)-P(1)-C(22) -1.79(17) C(1 )-C(2)-N(1)-Rh(1) 17.7(3) C(1 7)-C(1 6)-P(1)-C(22) -178.73(13) C(3)-C(4)-N(2)-N(1) 1.72(19) C(2 1)-C(1 6)-P(1 )-C(28) -104.65(15) C(5)-C(4)-N(2)-N(1) -176.69(16) C(1 7)-C(1 6)-P(1 )-C(28) 78.41(14) C(3)-C(4)-N(2)-B(1) -168.91(16) C(2 1)-C(16)-P(1)-Rh(1) 126.86(14) C(5)-C(4)-N(2)-B(1) 12.7(3) C(1 7)-C(1 6)-P(1 )-Rh(1) -50.08(14) C(2)-N( 1 )-N(2)-C(4) -2.35(18) C(27)-C(22)-P( 1 )-C(1 6) 116.69(16) Rh( 1 )-N( 1 )-N(2)-C(4) 168.64(10) C(23)-C(22)-P( 1 )-C(1 6) -62.02(16) C(2)-N(1 )-N(2)-B(1) 169.24(14) C(27)-C(22)-P(1)-C(28) -137.38(15) Rh(1 )-N(1)-N(2)-B(l) -19.78(17) C(23)-C(22)-P(1 )-C(28) 43.91(16) C(8)-C(7)-N(3)-N(4) -2.15(19) C(27)-C(22)-P( 1 )-Rh( 1) -5.93(17) C(6)-C(7)-N(3)-N(4) 173.80(15) C(23)-C(22)-P( 1 )-Rh( 1) 175.35(13) C(8)-C(7)-N(3)-Rh(1) 174.50(13) C(29)-C(28)-P(1)-C(1 6) -10.51(16) C(6)-C(7)-N(3)-Rh(1) -9.5(3) C(33)-C(28)-P(1)-C(1 6) 165.86(13) C(8)-C(9)-N(4)-N(3) -1.4(2) C(29)-C(28)-P( 1 )-C(22) -118.13(14) C(1 0)-C(9)-N(4)-N(3) 178.16(17) C(33)-C(28)-P(1 )-C(22) 58.24(14) C(8)-C(9)-N(4)-B(1) 164.43(17) C(29)-C(28)-P(1 )-Rh(1) 111.04(13) C(1 0)-C(9)-N(4)-B(1) -16.0(3) C(33)-C(28)-P(1 )-Rh(1) -72.59(14) C(7)-N(3)-N(4)-C(9) 2.20(18) C(34)-Rh( 1 )-P( 1 )-C( 16) 167.32(7) Rh(1)-N(3)-N(4)-C(9) -175.10(11) N(5)-Rh(1 )-P(1 )-C(1 6) -16.4(6) C(7)-N(3)-N(4)-B(1) -165.56(14) N(3)-Rh(1 )-P(1 )-C(1 6) -21.20(7) Rh(1)-N(3)-N(4)-B(1) 17.14(18) N(1)-Rh(1)-P(1)-C(1 6) 72.91(7) C( 1 3)-C( 1 2)-N(5)-N(6) -0.13(18) C(34)-Rh( 1 )-P( 1 )-C(22) -72.26(8) C( 11 )-C( 1 2)-N(5)-N(6) -179.74(15) N(5)-Rh( 1 )-P( 1 )-C(22) 104.0(6) C(1 3)-C(1 2)-N(5)-Rh(1) 172.94(12) N(3)-Rh(1 )-P(1 )-C(22) 99.22(7) C( 11 )-C(1 2)-N(5)-Rh(1) -6.7(3) N(1 )-Rh( 1 )-P(1 )-C(22) -166.68(7) C(1 3)-C( 1 4)-N(6)-N(5) -0.22(19) C(34)-Rh( 1 )-P( 1 )-C(28) 49.01(8) C(1 5)-C(1 4)-N(6)-N(5) 179.51(16) N(5)-Rh(1 )-P(1 )-C(28) -134.7(6) C(1 3)-C(14)-N(6)-B(1) -175.65(16) N(3)-Rh(1)-P(1)-C(28) -139.51(7) C(1 5)-C(1 4)-N(6)-B(1) 4.1(3) N(1 )-Rh(1 )-P(1 )-C(28) -45.41(7) C(1 2)-N(5)-N(6)-C(1 4) 0.21(18) Rh(1)-N(5)-N(6)-C(1 4) -174.44(11) 89

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