A Highly Regio- and Diastereoselective Phosphane-Catalyzed [3+2] Annulation of Morita-Baylis-Hillman Carbonates with Cyclic N-Acyl Ketimines

A highly regio- and diastereoselective phosphane-catalyzed [3+2] annulation of Morita-Baylis-Hillman (MBH) carbonates with cyclic N-acyl-substituted ketimines was developed. In the presence of the catalyst PBu3 (10 mol-%), a series of N-fused tricyclic products were obtained in excellent yields and diastereoselectivities under mild conditions. An example of a catalytic enantioselective annulation is also presented.