A Route to Highly Functionalized Stereospecific trans-Aminated Aurones from 3-Bromoflavones with Aniline and N-Phenylurea via a Domino Aza-Michael Ring Opening and Cyclization Reactions

Abstract

A facile cascade reaction is reported via aza-Michael addition, ring opening, and cyclization between 3-bromoflavone and aniline derivatives or N-phenylurea in the presence of KOt-Bu and CuI in DMF under mild reaction conditions. Products were obtained as stereospecific trans-aminated aurones in good to excellent yields (61–83%). Our protocol is operationally successful with ease, avoids the requirement of additives and ligands, and offers broad substrate scope.