Preparation of 6-Difluoromethylphosphonated Phenanthridines by Visible-Light-Driven Radical Cyclization of 2-Isocyanobiphenyls

A protocol to obtain a variety of 6-difluoromethylenephosphonated phenanthridines through a radical cyclization process was explored. These reactions, performed with the use of diethyl bromodifluoromethylphosphonate as a radical resource and 2-isocyanobiphenyls as radical acceptors, were smoothly triggered by visible-light photocatalysis. Electron-withdrawing and electron-donating groups were well tolerated, and the target molecules were obtained in excellent to moderate yields.