Chiral-at-Metal Rhodium(III) Complex Catalyzed Enantioselective Vinylogous Michael Addition of alpha,alpha-Dicyanoolefins with alpha,beta-Unsaturated 2-Acyl Imidazoles

摘要

As a development of traditional vinylogous Michael addition reactions, catalytic enantioselective gamma-functionalization of alpha,alpha-dicyanoolefins possesses a remarkable advantage in carboxylic derivatives synthesis and has emerged as a powerful tool for the preparation of high value chemicals. In another hand, the development of versatile and highly efficient catalyst is quite critical for such asymmetric transformations. Herein, a newly developed chiral-at-metal rhodium (III) complex catalyzed enantioselective vinylogous Michael addition of alpha,alpha-dicyanoolefins with alpha,beta-unsaturated 2-acyl imidazoles has been realized, delivering the corresponding adducts in 68-89 % yields with up to 95 % enantioselectivity. The reaction can be conducted on a gram-scale using a low catalyst loading (0.5 mol %) without impacting its efficiency.