Highly enantioselective synthesis of 2H-1-benzothiopyrans by a catalytic domino reaction

A highly enantio selective catalytic asymmetric synthesis of 2H-1-benzothiopyrans is presented. The organocatalytic asymmetric domino reactions between 2-mercaptobenzaldehyde and alpha,beta-unsaturated aldehydes proceed with excellent chemoand enantioselectivities to give the corresponding pharmaceutically valuable benzothiopyrans in high yields with 91-98% ee. (c) 2006 Elsevier Ltd. All rights reserved.