Organocatalytic cascade Michael/Michael reaction for the asymmetric synthesis of spirooxindoles containing five contiguous stereocenters

Abstract

A bifunctional squaramide-catalyzed Michael/Michael cascade reaction for the construction of five-membered spirooxindoles was developed. This reaction afforded the corresponding products with five contiguous stereocenters including a quaternary center in good to excellent yields (up to 93%) with excellent stereoselectivities (up to >99 : 1 dr, 98% ee). Meanwhile, the practicality of this methodology was illustrated by a gram-scale synthesis, one-pot four-component reaction and synthetic transformation of the resulting adduct.