Catalyst-Controlled Diastereodivergent Construction of Vicinal Sulfur-Functionalized Quaternary and Tertiary Stereocenters.

A catalyst-controlled diastereodivergence is described for the enantioselective conjugate addition of o-hydroxyphenyl-substituted p-QMs with 5 H-thiazol-4-ones. The reactions were enabled by two chiral complementary, nonenantiomeric catalysts to furnish a series of adducts possessing vicinal sulfur-functionalized quaternary and tertiary stereocenters in high yields with excellent asymmetric induction. Moreover, o-QMs generated in situ from o-hydroxybenzyl alcohols were also compatible.