Diastereo-and Enantioselective Aza-Morita-Baylis-Hillman-type Reaction Of Nitroalkenes To N-Tosylimines Catalyzed By Bifunctional Organocatalysts

The development of asymmetric Morita-Baylis-Hillman (MBH) reactions has evolved dramatically over the past few years, parallel to the emerging concept of bifunctional organocatalysis. Whereas organocatalysis is starting to compete with metal-based catalysis in several important organic transformations, the MBH reaction belongs to a group of prototypical reactions in which organocatalysts already display superiority over their metal-based counterparts. The first chapter summarizes recent mechanistic insights and advances in the design and synthesis of small organic molecules for enantioselective MBH and aza-MBH reactions.The second chapter has developed the first example of diastereo-and enantioselective aza-MBH-type reaction, which was accomplished by the asymmetric synthesis ofβ-nitro-y-enamines via a (1R,2R)-diaminocyclohexane thiourea derivative mediated tandem Michael addition and aza-Henry reaction in good yields (up to 95%), high enantio-selectivities (up to 91% ee) and diastereoselectivities (up to 1:99 dr). It is a noteworthy advantage of the organocatalyst that the new C-C bond-formation proceds efficiently with excellent diastereo-and enantioselectivity. To further probe the proton shift process, deuterium-labeled experiment was subjected to the reaction conditions.In the third chapter, we developed a new synthetic hexahydro pyrrolo[1,2-c]imidazole heterocycles method. Imine ylides formation by L-proline methyl ester and aldehyde, with N-Tos imine as substrate, afford [3+2] cycloaddition reaction to construction the hexahydro-pyrrolo[1,2-c]imidazole skeleton.