Asymmetric Cyclization Reactions Through an Enamine/Acid Cooperative Approach
MIAMI UNIVERSITY The Graduate School Certificate for Approving the Dissertation We hereby approve the Dissertation of Yongming Deng Candidate for the Degree: Doctor of Philosophy Hong Wang, Advisor Michael Novak, Committee Chair Scott Hartley, Reader Shouzhong Zou, Reader Annette Bollmann, Graduate School Representative ABSTRACT ASYMMETRIC CYCLIZATION REACTIONS THROUGH AN ENAMINE/ACID COOPERATIVE APPROACH. SYNTHESIS OF UNSYMMETRICALLY FUNCTIONALIZED BENZOPORPHYRINS by Yongming Deng The combination of enamine catalysis with metal catalysis, aiming to achieve organic transformations that cannot be accessed by enamine catalysis or metal catalysis independently, promises huge potential. The major obstacle in the development of enamine/metal Lewis acid combining catalysis is the incompatibility of the catalysts. The goal of this research is to solve this long lasting challenge and develop powerful asymmetric catalysts. Chapter one will provide a brief introduction to asymmetric catalysis and combing catalysis of enamine catalysis with transition metal catalysis. In Chapter two, the first application of arylamines in enamine catalysis is presented. The incompatibility of enamine catalysts and metal Lewis acid is solved by applying arylamines/acids cooperative catalysis. Through combination with either a metal Lewis acid or a chiral phosphoric acid, arylamines successfully catalyzed the asymmetric aldol reaction of cyclohexanone with both isatin and enones. Additionally, a highly chemo- and enantioselective three-component aza-Diels-Alder reaction was developed by combining arylamines with metal Lewis acids. In Chapter three, we devise a new type of chiral Lewis-acid-assisted Lewis acid catalyst formed from a metal Lewis acid and a chiral metal phosphate (MLA/M[P]3-LLA). A highly chemo- and enantioselective three-component aza-Diels-Alder reaction of cylic ketones (5, 6, and 7 membered) was successfully achieved by in situ prepared MLA/M[P]3-LLA.
[Show full text]