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Signature of Authon. Signtureof Athor I J -- Department of Chemistry 61/- May 15, 2007 The Development of Palladium-Catalysts for Organic Synthesis By Joseph R. Martinelli B.S. Chemical Engineering University of Wisconsin - Madison, 2002 Submitted to the Department of Chemistry in Partial Fulfillment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY IN ORGANIC CHEMISTRY at the Massachusetts Institute of Technology June 2007 © 2007 Massachusetts Institute of Technology All Rights Reserved -J o% - / Signature of Authon. Signtureof Athor I J -- Department of Chemistry 61/- May 15, 2007 Certified by: , , .- ..... Stephen L. Buchwald Camille Dreyfus Professor of Chemistry Thesis Supervisor Accepted by: Robert W. Field MASSACHUSETTS INSTITUTEr Haslam and Dewey Professor of Chemistry OF TECHNOLOGY Chairman, Departmental Committee on Graduate Students JULBRARIES1 12007 LIBRARI ES This doctoral thesis has been examined by a committee of the Department of Chemistry as follows: Professor Timothy F. Jamison: L' -_m it t is CommitteeChair Professor Stephen L. Buchwald: T,-S Thesis Supervisor Professor Sarah E. O'Connor: The Development of Palladium-Catalysts for Organic Synthesis By Joseph R. Martinelli Submitted to the Department of Chemistry on May 15, 2007 in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy at the Massachusetts Institute of Technology ABSTRACT Chapter 1. Suzuki-Miyaura coupling reactions of aryl and heteroaryl halides with aryl-, heteroaryl and vinyl boronic acids proceed in very good to excellent yield with the use of 2-(2',6'-dimethoxybiphenyl)- dicyclohexylphosphine, SPhos. Additionally, a comparison of the reactions with SPhos and with 2- (2',4',6'-triisoprocpylbiphenyl)-diphenylphosphine is presented that is informative in determining the relative importance of ligand bulk and electron-donating ability in the high activity of catalysts derived from ligands of this type. Further, when the aryl bromide becomes too hindered, an interesting C-H bond functionalization-cross-coupling sequence intervenes to provide product in high yield. Chapter 2. The direct transformation of aryl bromides into the corresponding Weinreb amides via Pd- catalyzed aminocarbonylation at atmospheric pressure is described. Electron-deficient, -neutral and -rich aryl bromides were all efficiently transformed to product. Furthermore, the process tolerates a wide variety of functional groups, is mild, and is operationally simple. Chapter 3. A general, functional group tolerant, and mild system for the Pd-catalyzed Heck carbonylation of aryl chlorides into the corresponding benzamides has been developed. This catalyst operates at one atmosphere of carbon monoxide using an inexpensive, air-stable and commercially available ligand. A variety of aryl chlorides were all successfully transformed to the corresponding amides using primary, a- branched primary, cyclic secondary, acyclic secondary, or aryl amines. Additionally, the mechanism of this reaction was studied using in situ IR spectroscopy and revealed the unique effect of sodium phenoxide in this reaction. Chapter 4. Pressurized microreactor systems greatly expand the range of reaction conditions and accelerate gas-liquid mass transfer. Heck aminocarbonylation reactions exemplify the potential for quickly and safely scanning of reagents and reaction conditions (1 to 15 bar and 100 - 160'C). The results reveal a general trend of increased yield of amide with temperature and selectivity for a-ketoamide production at lower temperature and higher pressure. Thesis Supervisor: Stephen L. Buchwald Title: Camile Dreyfus Professor of Chemistry ACKNOWLEDGMENTS Writing this section is proving to be more difficult than I anticipated. The more I think about it, the more people I want to thank. I suspect that if I thanked all the people that have helped me get to where I am, this would be the longest section of this document. I can't stop thinking of the phrase "standing on the shoulders of giants." I don't recall who coined this phrase, or in what context it was originally stated, but I believe this is an apt description of how I feel. First of all, I would like to thank my advisor Steve Buchwald. He was willing to accept me into his group even after he found out that I am allergic to cats and, consequently, don't like them much. I learned a great deal about science during my time in his group, including Buchwald's Experiments 1 - 5. I have also been instilled with and appreciate Steve's very high ethical standards. Steve and I bumped heads occasionally, but he taught me a lot and I am grateful for his guidance during my time at MIT. Steve is a great person, as illustrated by numerous gifts of Celtics and Red Sox tickets, and I am proud to have been a "Buchwaldian." I certainly would never have arrived at MIT had it not been for a number of amazing people I met in the chemistry department at the University of Wisconsin - Madison. My first organic lab T.A., Eric Voight, convinced me to pursue chemistry research and my undergraduate advisor, Prof. Steven D. Burke, was kind enough to accept me into his lab. I owe a considerable debt of gratitude to Prof. Burke. Not only did he make me feel like a valued group member, but also he was available any time I needed advice. I also received a lot of good advice from Lei Jiang, a gentleman I was lucky enough to work with both as an undergraduate and graduate student. I would also like to acknowledge Prof. Klavs F. Jensen. I had the good fortune of participating in collaboration with Prof. Jensen and two of his co-workers, Ed Murphy and Nick Zaborenko. Prof. Jensen is a great person and I really enjoyed working with him. He, Ed and Nick were all very patient with me and taught me a lot about engineering. Ed Murphy and Nick Zaborenko are both Sci-Fi junkies, like myself, and that really made working with them enjoyable. I would feel remiss if I did not mention the friends that kept me sane during my time as an undergraduate and graduate student. My long time friends and roommates all through college, Chris Mason and Scott Repa, were instrumental in helping me maintain my sanity. These two formidable minds were also excellent sources of motivation and often provided me with healthy doses of much needed humility. I am also indebted to my long time friend, Conan C., for his infallible abilities to make me laugh and keep me honest with myself. My classmates Tim Barder and Jon Wilson were absolutely essential components of my graduate career. Tim, also my lab mate and roommate, was another constant source of entertainment and humility. On more than one occasion I was sure Tim and I were going to kill each other, but we continue to be, and will remain, close friends. Jon Wilson is a great person and a true friend; with Jon's help I discovered that I am a terrible bowler. Matt Rainka was a great source of comic relief (a la the electric slide) and was a huge help during my time in the Buchwald group. Kelvin "PJ" Billingsley, the southern gentleman that he is, taught me a number of things, three of the most important lessons being that 1) "noon-ball" is amazing, 2) the only thing better than college basketball is college football and 3) Bud Light isn't terrible. The following individuals were all instrumental during my time at MIT and will remain valued friends: Mark Biscoe, Ed Hennessy, Eric Strieter, Mark Charles, John Naber, Tom Clark, Alex Shafir, Ryan Altman, Ana Minatti, Carrie Jones, Rachel Munday, David Surry, Don Watson, Catharine Larsen, Nan Zheng, Xiaohua Huang, Shawn Walker, Jackie Milne, Carlos Burgos, Andreas Kellas, Alan Hyde, Ruben Martin, Gordon Brasche, Nan Zheng, Elaine Lee, Liane Klingensmith, and Daemian Dussault. I apologize to anyone that I may have forgotten to mention. Finally, I would like to thank my family for being the great people that they are. My parents have always been supportive of me, and I will always be thankful for their love and support. My brothers, Mike and Jeff, have been great friends and are always there when I need them; even if I require several days to return a phone call. My sister-in-law, Kristina, was often in Boston for work during my first few years and she would frequently buy me a nice dinner. The rest of my family, including my little niece and nephew (Maddy and Conner), has all been great. Everyone mentioned in this section has been amazing and I could never have made this journey without you. PREFACE This thesis has been adapted from the following published articles co-written by the author: "Catalysts for Suzuki-Miyaura Coupling Processes: Scope and Studies of the Effect of Ligand Structure" Barder, T.E.; Walker, S.D.; Martinelli, J.R.; Buchwald, S.L. J. Am. Chem. Soc. 2005, 127, 4685. "Convenient Preparation of Weinreb Amides via Pd-Catalyzed Aminocarbonylation of Aryl Bromides at Atmospheric Pressure" Martinelli, J.R.; Freckmann, D.M.M.; Buchwald, S.L. Org. Lett. 2006, 8, 4843. "Accelerating Reactions with Microreactors at Elevated Temperature and Pressures: Profiling Aminocarbonylation Reactions" Murphy, E.R.; Martinelli, J.R.; Zaborenko, N.; Buchwald, S.L.; Jensen, K.F. Angew. Chem. Int. Ed. 2007, 46, 1734. Respective Contributions This thesis contains work that is the result of collaborative efforts between the author and other workers at MIT. An overview detailing the specific contributions of the author is included below. The work described in Chapter 1 was the result of a collaborative between Dr. Shawn Walker, Tim Barder and the author. The specific contributions of the author include the reactions shown in Table 5, the room temperature reactions discussed in the text, and the synthesis of the ligand used in Table 5 (ligand 2). The other work was conducted by either Tim Barder or Dr. Shawn Walker and was included for the sake of continuity.
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