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.