Transition Metal-Free Oxidative Radical Decarboxylation/Cyclization for the Construction of 6-Alkyl/Aryl Phenanthridines.

A radical cascade decarboxylation/cyclization of 2-isocyanobiphenyls with aliphatic carboxylic acids as well as aromatic carboxylic acids under the transition metal-free conditions was reported. This process, which included formation of two new C-C bonds and cleavage of C-COOH bonds, afforded a novel and environmentally friendly approach to producing 6-alkyl/aryl phenanthridines with moderate to good yields.