Copper-catalyzed oxidative cleavage of carbon–carbon double bond of enol ethers with molecular oxygen

A novel CC bond cleavage reaction of aromatic enol ethers (1) to give ketones (2) using molecular oxygen as oxidant is described. Among the examined catalysts (Cu(II), Pd(II), Ru(II), and H+), CuCl2 exhibited the highest activity. The reaction proceeded smoothly with several kinds of substrates.

Graphical abstractUsing CuCl2 as catalyst, aromatic enol ethers were oxidatively cleaved to give ketones under O2 atmosphere. On the other hand, the same substrates were hydrolyzed to give aldehydes under Ar atmosphere.Figure optionsDownload full-size imageDownload as PowerPoint slide