Dichloromethane-promoted photo-induced aerobic oxidation of methylarenes

We present a novel, efficient, and sustainable strategy for the aerobic oxidation of methylarenes to valuable carbonyl products using dichloromethane (DCM) as both solvent and promoter under photo-irradiation. Unlike conventional approaches, this reaction does not require any metal-based or external organic catalysts, relying solely on dichloromethane to facilitate the selective activation of benzylic C–H bonds. This metal- and catalyst-free method exhibits high yields, excellent selectivity, and mild reaction conditions under ambient air atmosphere. Mechanistic studies indicate that DCM plays a critical role in generating chlorine radicals under photo-irradiation, effectively promoting hydrogen atom transfer (HAT) and subsequent oxidation processes. This innovative approach provides a mild, cost-effective, and industrially promising alternative for the selective oxidation of aromatic hydrocarbons.