New protocol of copper-catalyzed oxidative C(CO)C bond cleavage of aryl and aliphatic ketones to organic acids using O2 as the terminal oxidant

Catalytic oxidation of C C bond is a key technology to transform petroleum-based as well as sustainable biomass feedstock into more valuable oxygenates. We herein describe a convenient and useful oxidation strategy of converting ketones into carboxylic acids using homogeneous copper catalyst without additives and with O 2 as the terminal oxidant. A wide range of aryl and aliphatic ketones as well as β–O–4 lignin models were selectively oxidized to acids via C C bond cleavage. Mechanism studies by EPR and in situ NMR elucidate the principles of Cu/O 2 reactivity that involves C H bond and O 2 activation via a peroxide species. This provides an important foundation for expanding the scope of useful aerobic oxidation reactions using copper catalysts.