Stereoselective one-pot synthesis of polycyanosubstituted piperidines

Abstract

An effective and facile multicomponent method for the synthesis of polysubstituted piperidines is described. The Michael–Mannich type cascade of benzylidenemalononitriles with aromatic aldehydes and ammonium acetate or aqueous ammonia provides convenient access to the stereoselective synthesis of 3,3,5,5-tetracyano-2,4,6-triarylpiperidines in good to excellent yields in one-pot manner. Ammonium acetate or aqueous ammonia plays a role both as a catalyst and as a nitrogen source. It is established that the reaction proceeds via sequence of equilibriums and a competitive mechanisms are implemented.