Single-atom Cu catalysts for the oxidative coupling of styrenes with aryl sulfones: from salts and zeolites to MOFs

Abstract

[EN] Oxidative couplings in organic synthesis are typically performed with unrecoverable precious metal catalysts in solution. Here we show that CuCO3, Cu-supported zeolites and Cu-metal organic frameworks (MOFs) can replace AgNO3 as a catalyst for the oxidative coupling of styrenes with aryl sulfones, to give styrenyl sulfones. The single Cu atoms supported in zeolites show higher catalytic activity than the Cu salt as the basicity of the zeolite framework increases, to match the carbonate salt, and when embedded directly into a MOFs ' walls with oxamate ligands (thus with the proper electronic environment) they can be recycled for at least five times without any depletion in catalytic activity. These results showcase not only the substitution of a noble metal (Ag) by an abundant metal (Cu) in a metal-catalyzed oxidative coupling reaction, but also going from a salt to a supported solid catalyst, of high significance from a sustainable point of view.