Highly Enantioselective Michael Addition Reactions of 3-Substituted Benzofuran-2(3H)-ones to Chalcones Catalyzed by a Chiral Alkyl-Substituted Thiourea

A highly enantioselective Michael addition of 3-substituted benzofuran-2(3H)-ones to chalcones catalyzed by a chiral bifunctional thiourea was developed. Several chiral 3,3'-substituted benzofuran-2(3H)-ones derivatives, bearing adjacent quaternary-tertiary stereocenters, were efficiently synthesized with excellent enantioselectivities.