Regioselective control of the thiocarbonylation of terminal acetylenes with arylthiols catalyzed by Pd(II) and diphosphine ligands

Control of the regioselective thiocarbonylation of terminal acetylenes 1a–e with arylthiols 2a,b was successfully achieved by using Pd(OAc)2 and 1,4-bis(diphenylphosphino)butane (dppb), or 1,3-bis(diphenylphosphino)propane (dppp), as catalysts. The formation of the thioesters 3 or 4 depends mainly on the type of ligand (dppp or dppb) and the solvent (THF or CH2Cl2) under CO/H+ or syngas mixture.