Enantioselective Organocatalytic Double Michael Addition Reactions

A novel organocatalytic, enantioselective domino double Michael addition reaction of α,β-unsaturated aldehydes with ethyl 4-mercapto-2-butenoate has been developed. The process is promoted by chiral diphenylprolinol TMS ether to give chiral tetrahydrothiophenes in high to excellent levels of enantioselectivities.