Visible-Light-Mediated Synthesis of Unsymmetrical Diaryl Sulfides via Oxidative Coupling of Arylhydrazine with Thiol.

A metal-free visible-light-promoted oxidative coupling between thiols and arylhydrazines has been developed to afford diaryl sulfides using a catalytic amount of rose bengal as photocatalyst under aerobic conditions. A library of unsymmetrical diaryl sulfides with broad functionalities was synthesized in good yields at room temperature. The present methodology is also applicable to benzo[ d]thiazole-2-thiols, benzo[ d]oxazole-2-thiol, 1 H-benzo[ d]imidazole-2-thiols, and 1 H-imidazole-2-thiol.