Direct catalytic asymmetric intramolecular conjugate addition of thioamide to α,β-unsaturated esters

Proton transfer allows efficient access to optically active five- and six-membered ring systems bearing ester and thioamide functionalities in an anti fashion; these ring systems are amenable to differential functional group manipulation. Direct catalytic, asymmetric, intramolecular conjugate addition of thioamide to α,β-unsaturated esters is described. In situ generated Cu thioamide enolate, by catalytic deprotonation, underwent the conjugate addition/protonation, to achieve the complete transformation (see scheme).