A novel three-component reaction of N-fluoropyridinium salts: a facile approach to imidazo[1,2-a]pyridines

The reaction of N-fluoropyridinium triflate with isonitriles in acetonitrile and propionitrile in the presence of NaBH(OAc)3 led to the formation of the corresponding imidazo[1,2-a]pyridines in 44–73% yields. The proposed reaction mechanism involves the intermediate formation of a highly reactive carbene species and apparent reduction of the pyridinium intermediate with NaBH(OAc)3 to yield the targeted heterocycles.