Intramolecular Aromatic C–H Acyloxylation Enabled by Iron Photocatalysis

A mild and efficient protocol for the intramolecular aromatic C–H oxygenation of 2-biphenylcarboxylic acids has been achieved via iron photocatalysis. The 2-biphenylcarboxylic acids with a diverse array of substituents at both phenyl rings could furnish the oxygenation products in good to excellent yields. We speculate that the aryl carboxylate–iron(III) complexes should generate the aroyloxy radicals and iron(II) upon visible light irradiation.