Electro-Oxidative S-H/S-H Cross-Coupling with Hydrogen Evolution: Facile Access to Unsymmetrical Disulfides

Sulfur is an essential element because it exists widely in proteins. The disulfide bond is an important moiety in many different types of significant organic molecules. A new approach for oxidant- and catalyst-free S-H/S-H cross-coupling, with hydrogen evolution, to construct unsymmetrical disulfides was developed. Under the conditions of an undivided cell at room temperature, a series of unsymmetrical disulfides were prepared with up to 87 % yield from the direct coupling of an aryl mercaptan and alkyl mercaptan. Gram-scale synthesis also highlights the synthetic utility of this electrochemical strategy.