Organocatalytic Enantioselective Conjugate Addition of Azlactones to Enolizable Linear and Cyclic Enones.

Highly diastereo- and enantioselective conjugate additions of azlactones to enolizable cyclic and linear enones were conducted by employing proline aryl sulfonamide as the organocatalyst in trifluorotoluene. The conjugate adducts bearing contiguous quaternary and tertiary stereocenters were obtained in moderate to good yields with excellent diastereoselectivities and moderate to good enantioselectivities. This developed protocol filled in the substrate gap for the organocatalytic conjugate addition of azlactone to enones.