Photocatalyzed intermolecular C–N bond formation for the synthesis of imidazo[1,2-a]pyridines

[Display omitted] Photocatalyzed intermolecular CN bond formation of 2-aminopyridines with ketones choosing NH4I as the catalyst was explored, affording imidazo[1,2-a]pyridines under milder conditions. The reaction induced by sunlight is able to provide the corresponding products. Our catalytic system is suitable for the reaction of 2-aminopyridine, ketones and sulfide derivatives. Furthermore, the protocol is also applicable for the reaction of 2-aminopyridine and sulfoxonium ylide.