Visible light induced regioselective C-3 thiocyanation of imidazoheterocycles through naphthalimide dye based photoredox catalysis

A visible light induced C-3 thiocyanation of imidazo[1,2-a]pyridines by using a naphthalimide based photoredox catalyst has been reported. Tolerance of electron withdrawing and donating groups at different positions of the imidazo[1,2-a]pyridine ring led to a wide substrate accessibility of this method. This methodology is further reproducible with other heterocycles like benzo[d]imidazo[2,1-b]thiazoles, indoles, azaindoles, and anilines. A visible light induced C-3 thiocyanation of imidazo[1,2-a]pyridines and various other heterocycles (benzo[d]imidazo[2,1-b]thiazoles, indoles, azaindoles, and anilines) was performed using a naphthalimide based photoredox catalyst.