Electromagnetic milling promoted mechanochemical Copper-Catalyzed C-O coupling reaction for diaryl ether formation

Abstract

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, no additional heating, and short reaction time, which features a wide substrate scope, good functional group tolerance, and efficient gram-scale synthesis. A ligand derivated from the oxalic diamide was synthesized and utilized in the solid-state coupling, which exhibited excellent activity to the C-O bond formation under solid state. Control experiments via infrared (IR) spectroscopy showed the possible formation of Cu(I)-O intermediates with the high-speed rotating electromagnetic rod in the magnetic field. Additionally, it opens up extensive possibilities for the chemical bond activation and construction under multi energy-field coupling.