Arylamine Photocatalyst-Induced Addition/Cyclization of 2-Allylaminobenzonitriles with gem-Difluoromethyl Radical for Assembling Phenanthridine Derivatives

A transition metal-free photocatalytic addition/cyclization of 2-allylaminobenzonitriles with gem-difluoromethyl radicals has been developed, constructing phenanthridine derivatives in moderate to good yields. The strongly reducing arylamine was employed as a photocatalyst in the reaction, which tolerated tertiary amines and efficiently enabled the conversion of gem-difluoromethyl radical precursors into radical species. The obtained novel phenanthridine derivatives exhibited blue to green emissions at the range of 390-540 nm, showing potential application in fluorescent dye.