Highly diastereo- and enantioselective catalytic domino thia-Michael/Aldol reactions: Synthesis of benzothiopyrans with three contiguous stereocenters

Highly enantioselective organocatalytic domino thia-Michael/aldol reactions between 2-mercaptoacetophenone and alpha,beta-unsaturated aldehydes are presented. The reactions proceed with excellent chemo-, diastereo- and enantioselectivity to give the corresponding benzothiopyran derivatives in high yields with up to > 15:1 dr and 96 to > 99% ee.