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.