Bifunctional Cinchona Sulfonamides in Asymmetric Michael Reaction

Significance

A novel bifunctional catalyst 1, which uses the cinchona alkaloid core as the ­stereocontrolling element and an N-sulfonamide moiety for single hydrogen-bonding catalysis, was employed in an enantioselective Michael addition. This quaternary carbon-forming reaction afforded the products in excellent yields and enantioselectivities, though diastereoselectivity was generally moderate. The catalyst is thought to activate both the nucleophile and the electrophile by hydrogen bonding with the quinuclidine nitrogen and the N-sulfonamide group, respectively.