Palladium-Catalyzed Regioselective Three-Component Cascade Bisthiolation of Terminal Alkynes

An efficient and novel NHC(N-heterocyclic carbene)-palladium-catalyzed three-component cascade bisthiolation of terminal alkynes, K2S (potassium sulfide) and diaryliodonium salts for the assembly of functionalized (Z)-1,2-bis(arylthio)alkene derivatives has been accomplished for the first time. This unique observation features a broad substrate scope, excellent functional-group tolerance, and high regioselectivity. Especially, an arylthiolate anion from diaryliodonium salts and potassium sulfide was proposed as the key intermediate in the catalytic cycle.