Regioselective, Solvent‐ and Metal‐Free Chalcogenation of Imidazo[1,2‐ a ]pyridines by Employing I 2 /DMSO as the Catalytic Oxidation System

Highly efficient molecular‐iodine‐catalyzed chalcogenations (S and Se) of imidazo[1,2‐ a ]pyridines were achieved by using diorganoyl dichalcogenides under solvent‐free conditions. This approach afforded the desired products that had been chalcogenated regioselectively at the C3 position in up to 96 % yield by using DMSO as an oxidant, in the absence of a metal catalyst, and under an inert atmosphere. This mild, green approach allowed the preparation of different types of chalcogenated imidazo[1,2‐ a ]pyridines with structural diversity. Furthermore, the current protocol was also extended to other N ‐heterocyclic cores.