Catalytic asymmetric conjugate addition of various α-mercaptoketones to α,β-unsaturated N-acylated oxazolidin-2-ones with bifunctional organocatalyst

A bifunctional squaramide catalysed enantioselective conjugate Michael addition reaction of various α-mercaptoketones to α,β- unsaturated N-acylated oxazolidinones under mild reaction conditions has been developed. This catalytic reaction afforded the corresponding adducts in good yields with high enantioselectivities (up to 92% ee). This is the first example of organocatalysed sulfa-Michael addition using various α-mercaptoketones as the Michael donors.