Construction of a 4H-pyrido[4,3,2-gh]phenanthridin-5(6H)-one skeleton via a catalyst-free radical cascade addition/cyclization using azo compounds as radical sources

Abstract

A new radical addition/cyano insertion/homolytic aromatic substitution cascade reaction initiated by the thermal homolysis of azo compounds to access polycyclic phenanthridine derivatives has been developed. Under the catalyst and oxidant free conditions, a broad range of N-arylacrylamides are compatible to afford the desired 4H-pyrido[4,3,2-gh]phenanthridin-5(6H)-one derivatives in moderate to high yields.