Green Synthesis of Aryl Thioethers through Cu-catalysed C-S Coupling of Thiols and Aryl Boronic Acids in Water

An efficient, practical, highly selective and environmentally benign method is reported for the synthesis of aryl thioethers via the coupling of thiols with aryl boronic acids in the presence of NaOH and a catalytic amount of CuSO4 at 130 degrees C using water as a green solvent. The products were obtained in moderate to excellent yields; more importantly, the use of toxic ligands and solvents was avoided. A broad range of aryl boronic acids and scalable processes make this methodology valuable and versatile for the synthesis of a broad range of aryl sulfides.