Synthesis of 2,3-bifunctional imidazo[1,2- a ]pyridines through cycloadditions of pyridinium ylides with N -cyano-4-methyl- N -phenylbenzenesulfonamide

Imidazo[1,2- a ]pyridine is recognized as a “drug prejudice” due to its wide applications in medicinal chemistry. In this work, we developed a [3 + 2] cycloadditions/oxidation reaction of pyridinium ylides with N -cyano-4-methyl- N -phenylbenzenesulfonamide for the synthesis of 2,3-bifunctional imidazo[1,2- a ]pyridines. The N -cyano-4-methyl- N -phenylbenzenesulfonamide serves as an activated nitrile, exhibiting higher activity than common alkyl or aryl nitrile in the reaction. The strategy features high chemoselectivity, easily accessible materials, and broad substrate scope. The scale-up reaction demonstrated the practicability of this method, and the imidazo[1,2- a ]pyridines products could be easily transformed into their derivatives.