Visible Light-Induced Aerobic Ring-Opening Oxidation of Unstrained Aryl Cycloalkanes

The cleavage of unstrained C-C bonds presents a significant challenge in synthetic chemistry. Herein, we disclose a visible light-induced aerobic ring-opening oxidation of unstrained aryl cycloalkanes using low-cost 2-bromoanthraquinone (2-BrAQ) as the photocatalyst. This mild and practical protocol provides efficient and regioselective access to linear aromatic ketones from a wide range of substrates. Moreover, the strategy is also effective for selective C(sp³)-C(sp³) bond cleavage of aryl-substituted linear alkanes. Preliminary mechanistic studies suggest that the transformation likely proceeds through a hydrogen atom transfer between photoexcited 2-BrAQ and the benzylic C-H bond to generate a delocalized benzylic radical, followed by ring opening via β-scission of an alkoxy radical to afford a distal alkyl radical.