Organocatalyzed asymmetric formal [3 + 2] cycloaddition of isocyanoacetates with N-itaconimides: facile access to optically active spiropyrroline succinimide derivatives

Abstract

An efficient organocatalytic asymmetric formal [3 + 2] cycloaddition reaction of α-aryl isocyanoacetates with N-aryl or alkyl substituted itaconimides catalyzed by a dihydroquinine derived squaramide catalyst has been investigated, which affords the corresponding spiropyrroline succinimide derivatives with two non-adjacent quaternary–quaternary stereocenters in moderate to good yields (up to 82%) with moderate to excellent diastereoselectivities (up to >20 : 1 dr) and excellent enantioselectivities (90–>99% ee) under mild conditions.