Enantioselective direct Michael addition of cyanohydrin ether derivatives to enones catalyzed by chiral bis(guanidino)iminophosphorane organosuperbase

Abstract

The direct use of cyanohydrin ether derivatives as less acidic pronucleophiles was achieved for the first time in the catalytic enantioselective Michael addition reaction under transition metal free conditions. Chiral bis(guanidino)iminophosphoranes as the higher order organosuperbase facilitated the intended catalytic Michael addition to enones, giving rise to the corresponding products in high yields with moderate to high diastereo- and enantioselectivities in most cases. Further elaboration of the corresponding enantioenriched product was conducted by derivatization into a lactam derivative through hydrolysis followed by cyclo-condensation.