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New Applications of Cyclobutadiene Cycloadditions: Diversity and Target Oriented Synthesis

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New Applications of Cyclobutadiene Cycloadditions: Diversity and Target Oriented Synthesis Author: Jason Joseph Marineau Persistent link: http://hdl.handle.net/2345/1741 This work is posted on eScholarship@BC, Boston College University Libraries. Boston College Electronic Thesis or Dissertation, 2010 Copyright is held by the author, with all rights reserved, unless otherwise noted. Boston College The Graduate School of Arts and Sciences Department of Chemistry NEW APPLICATIONS OF CYCLOBUTADIENE CYCLOADDITIONS: DIVERSITY AND TARGET ORIENTED SYNTHESIS a dissertation by JASON JOSEPH MARINEAU submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy December 2010 © Copyright by JASON JOSEPH MARINEAU 2010 New Applications of Cyclobutadiene Cycloadditions: Diversity and Target Oriented Synthesis Jason J. Marineau Thesis Advisor: Professor Marc. L. Snapper Abstract Cyclobutadiene cycloadditions provide rapid access to rigid polycyclic systems with high strain energy and unusual molecular geometries. Further functionalization of these systems allows entry into unexplored chemical space. A tricarbonylcyclobutadiene iron complex on solid support enables exploration of these cycloadditions in a parallel format amenable to diversity oriented synthesis. Modeling of the cycloaddition transition states with density functional calculations provides a theoretical basis for analysis of the regioselectivity observed in generation of these substituted bicyclo[2.2.0]hexene derivatives. The high strain energy accessible in cyclobutadiene cycloadducts and their derivatives renders them useful synthons for access to medium-ring natural products through ring expansion. Torilin, a guaiane sesquiterpene isolated from extracts of the fruits of Torilis japonica, exhibits a range of biological activities including testosterone 5 -reductase inhibition, hKv1.5 channel blocking, hepatoprotective, anti-inflammatory and anti-cancer effects. These activities are reviewed and analyzed from the perspective of a common biochemical target. Tandem oxidation and acid-catalyzed rearrangement of a highly strained tetracyclo[5.3.0.01,5.02,4]decane in the presence of tetrapropylammonium perruthenate provides the bicyclo[5.3.0]decane core of this natural product with complete control of relevant stereochemistry. The complex precursor required for this rearrangement is rapidly accessed by cyclopropanation of an intramolecular cyclobutadiene cycloadduct. Synthetic studies are reported which provide preliminary access to 8-deoxytorilolone. Acknowledgements I would like to thank everyone who has supported me on this long journey and made it all possible. I could not have done it without my family and their patience, understanding and encouragement. I would first and foremost like to thank my wife Sara Marineau. You’ve been there through everything, enjoyed the highs with me when things were working and pulled me back out of the lows when things failed. You endured the long hours in the lab and were always ready to listen. We make a great team, you and I. You did your best to learn the in’s and out’s of cyclobutadiene, NMR, cyclopropanation and other things that were barely in English and even proof read a thesis about them. You never stopped believing in me, even when I doubted myself. Thank you so much, I would not have made it here without you. I love you! To my parents, Sue and Joe Marineau, I obviously would not be where I am today without you. Thank you for teaching me to work hard and always strive for the best. I could not have done it without your patient words of encouragement and constant support. I’d like to thank the Campbells. Sue, Jerry, Lindsey, Mary. You cared so much about what I was doing and listened to all the stories. Thank you so much for all your prayers and support. I’d like to thank Marc for some very interesting projects and the freedom to pursue them in the ways I saw fit. I may not have always understood what you i were doing at the time, but in the end I know that my research turned out better because of it. Thank you for the opportunity to grow as a scientist and learn to solve some good problems. The Snapper lab has been a great place to work and I have made a lot of good friends along the way. It has been a fun and supportive environment in which to do chemistry. I’d like to thank all of the members, past and present who I’ve been lucky enough to work with. In particular, I’d like to thank Michael Williams for stepping in to share some hood space with me that first year and along with Andy Leyhane, teaching me the ins and outs of the Iron project. To Dave Finnegan, my fellow WPI alum, thanks for all the interesting and wide ranging discussions and for helping to pass down your share of lab lore. I had the pleasure of sharing my time in lab with two other Jasons, Gavenonis and Rodrigo. We certainly had some great times while giving Marc less names to remember. Thanks for all the discussions over coffee and always being there to bounce ideas off. Thanks too for helping proof read this thesis. I’d like to thank Jing He, for generous donations of iron compound to my cause when I was trying to get everything wrapped up and for doing a great job taking on most of the group responsibilities as the remaining senior member. Best of luck, I’m sure you’ll do very well! I’d also like to thank two talented undergraduates whom I was fortunate enough to work with, Michael Millonig and Doug Rioux. I had a great time mentoring you guys and all your hard work certainly helped me move the project forward. While perhaps not a group member in the traditional sense, I’d ii like to thank Deb Lynch. You were always there with conversation (and candy) and it seems like you could fix just about any non-chemistry problem in the department. The BC Chemistry Department is a wonderful group of people and a great place to do graduate work. I’ve made so many friends over the years and always appreciated the collaborative nature of all the groups. It was a rare problem that could not be solved by talking to the right person, and in that case, they were there to commiserate. I’d like to thank Ross Kelly for reading my progress reports over the years, you always had helpful suggestions and I enjoyed those discussions. I also enjoyed getting to teach with you and preparing all the exciting demonstrations. My teaching also would not be where it is today without Christine Goldman. We had the pleasure of teaching together for a number of years and I learned a ton, especially from the excitement and innovation you brought to every class. Getting to help you design and implement a brand new lab class was also one of my best teaching experiences. Finally, I’d like to thank my thesis committee, Dr. Scott, Kian, Jason, Marc, I really appreciate the time you spent working with me on this document and the helpful suggestions and discussions that really made it all come together. iii Table of Contents Chapter 1: Studies on the Biological Activity of Torilin .......................................... 1 INTRODUCTION .............................................................................................. 1 Anti-Inflammatory .............................................................................................. 3 Anti-Cancer Activity ......................................................................................... 12 Anti-Microbial Activity ...................................................................................... 19 Other Activities ................................................................................................ 22 Testosterone 5 -Reductase Inhibition ......................................................... 22 Hepatoprotective Activity ............................................................................. 26 hKv1.5 Channel Blockade ........................................................................... 26 Inhibition of Melanin Production .................................................................. 27 CONCLUSIONS .............................................................................................. 29 Chapter 2: Cycloadditions of Solid-Supported Cyclobutadiene .......................... 32 Introduction ..................................................................................................... 32 General Introduction .................................................................................... 32 Background ................................................................................................. 33 RESULTS AND DISCUSSION ........................................................................ 36 Preparation of Iron Cyclobutadiene Functionalized Polystyrene ................. 36 Intermolecular Cycloadditions ..................................................................... 37 Solution Phase Cycloadditions ................................................................ 37 Solid-Supported Cycloadditions ............................................................... 39 Density Functional Calculations .................................................................. 43 iv SUMMARY ...................................................................................................... 48 EXPERIMENTAL ............................................................................................ 50 General Information ..................................................................................... 50 Experimental Procedures ...........................................................................
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