Transition Metal Catalyst-Free C-3 Sulfonylmethylation of Imidazo[1,2- a ]pyridines with Glyoxylic Acid and Sodium Sulfinates in Water.

Herein, we describe an efficient and benign protocol for direct C-3 sulfonylmethylation of imidazo[1,2- a ]pyridines with glyoxylic acid and sodium sulfinates. Various sulfonylmethylated imidazo[1,2- a ]pyridines were synthesized in water under transition metal catalyst-free conditions. This multicomponent reaction featured available substrates, good functional group tolerance, moderate to excellent yields, and mild reaction conditions.