Novel Chiral Bifunctional L‐Thiazoline‐Thiourea Derivatives: Design and Application in Enantioselective Michael Reactions

Several novel chiral bifunctional L‐thiazoline‐thiourea derivatives were easily synthesized from commercially available L‐cysteine in high yield. These catalysts were subsequently applied to the enantioselective Michael addition of acetylacetone to β‐nitrostyrenes. The products with S configuration were obtained in 98% enantiomeric excess (ee) when the L‐thiazoline‐thiourea derivatives were used. A plausible transition state model is proposed to explain the observed enantioselectivities. Chirality 27:979–988, 2015. © 2015 Wiley Periodicals, Inc.