Transition-Metal-Free Three-Component Reaction: Additive Controlled Synthesis of Sulfonylated Imidazoles.

Two efficient transition-metal-free highly regioselective pathways for constructing sulfonylated imidazoles via three-component reactions of amidines, ynals, and sodium sulfonates have been developed. The generations of different sulfonylated imidazoles were simply controlled by additives. In addition, this method features environmental friendliness, good functional group tolerance, and high atom economy, which makes it practical.