Organocatalytic asymmetric vinylogous Michael addition of 3-alkylidene oxindoles to α-substituted β-nitroacrylates: facile construction of a chiral all-carbon quaternary center

Abstract

A highly enantioselective vinylogous Michael addition reaction of 3-alkylidene oxindoles to α-substituted β-nitroacrylates has been developed by using a cinchona alkaloid-squaramide bifunctional organocatalyst, which provides a series of chiral products bearing all-carbon quaternary stereocenters in excellent yields with high enantioselectives (up to 97%).