Electromagnetic milling promoted mechanochemical copper-catalyzed C–O coupling reaction for diaryl ether formation†

A novel copper-catalyzed C–O coupling reaction promoted by electromagnetic milling (EMM) has been reported for the mild and efficient synthesis of various diaryl ethers. This transformation could be realized without solvent and additional heating in a short reaction time, and features a wide substrate scope, good functional group tolerance, and efficient gram-scale synthesis. A ligand derived from oxalic diamide was synthesized and utilized in the solid-state coupling, which exhibited excellent activity towards C–O bond formation under solid state conditions. Additionally, it opens up extensive possibilities for chemical bond activation and construction under multi-energy field coupling conditions.