I₂-DMSO Promoted Direct Synthesis of Substituted Imidazoles from Styrene and Benzylamine under Solvent-free Conditions

A novel and efficient method has been developed for the direct synthesis of substituted imidazoles through the reaction of styrene and benzylamine with the assistance of I₂-DMSO concerted system. The reactions proceed efficiently under open air and solvent-free condition to afford a wide variety of substituted imidazole compounds in good yields. A productive large-scale synthesis also has been performed to target highly substituted heterocyclic motifs. The present protocol offers metal and solvent-free process, mild conditions, easily accessible reactants, and operational simplicity to achieve an assembly of substituted N-heterocyclic compounds.