Organocatalytic enantioselective transient enolate protonation in conjugate addition of thioacetic acid to α-substituted N-acryloyloxazolidinones

Organocatalytic conjugate addition of thioacetic acid to a series of α-substituted N-acryloyloxazolidin-2-ones followed by enantioselective protonation has been studied in the presence of thiourea catalysts derived from cinchona alkaloids. Conjugate addition/protonation adducts have been obtained up to 97% ee and high yields. The methodology could serve as an easy and practical route to the syntheses of useful biologically active molecules.