Photo-Mediated Aromatic C-H Activation by Cu(II)-Amido-Quinoline Complexes

Abstract

A sustainable and selective photo-mediated strategy for aromatic C–H hydroxylation is reported using Cu(II)-amido-quinoline complexes under mild conditions (50 °C). This method enables the efficient hydroxylation of benzene, achieving a conversion of ~60% with 90% selectivity toward phenol. This work highlights a green and practical approach to the selective functionalization of substituted arenes, offering valuable implications for the synthesis of key industrial intermediates such as 2,5-DCP, a precursor to the widely used herbicide Dicamba, and overcoming the typical challenge of isomer separation limitations of conventional multi-step synthesis. Mechanistic investigations, including kinetic isotope effect (KIE) measurements, product analysis, and electron paramagnetic resonance (EPR) spectroscopy, support a Fenton-type reaction pathway involving the generation of hydroxyl radicals.