Visible light-initiated cross-coupling between thiophenols and aryl halides (X = I and Br) to synthesize aryl thioethers over Pd/ZnIn2S4

Abstract

The coupling between aryl halides and thiols to synthesize aryl thioethers via the formation of a C–S bond is an important reaction. In this manuscript, a Pd/ZnIn₂S₄ nanocomposite obtained via photoreduction of PdCl₂(CH₃CN)₂ in the presence of ZnIn₂S₄ was found to be an efficient bifunctional catalyst to realize the coupling reaction between thiophenols and aryl halides (X = Br and I) to yield aryl thioethers. A mechanism study reveals that the reaction involves the light-initiated generation of thiyl radicals as important intermediates. This reaction protocol can be applied to a wide range of substrate scopes, with moderate to excellent yields for the desired thioethers. This study provides a facile, green and economic strategy for the synthesis of aryl thioethers under mild conditions. This work also highlights the great potential of semiconductor-based photocatalysis in light-initiated organic syntheses.