Photocatalytic 1,3-oxyheteroarylation of aryl cyclopropanes with azine <i>N</i>-oxides

Abstract

Cyclopropanes, valuable C3 building blocks in organic synthesis, possess high strain energy and inherent stability. We present an efficient, environmentally benign 1,3-oxyheteroarylation of aryl cyclopropanes using azine N-oxides as bifunctional reagents under visible light irradiation. This metal-free method yields beta-pyridyl ketones under mild conditions. Mechanistic studies reveal a photo-induced radical pathway involving single-electron oxidation of both aryl cyclopropanes and azine N-oxides, followed by stepwise ring opening. The dual oxidation mechanism accommodates diverse cyclopropane and azine N-oxide combinations based on their oxidation potentials. This green chemistry method enhances the synthetic utility of aryl cyclopropanes while introducing an efficient strategy for their difunctionalization. The methodology aligns with sustainable organic synthesis principles, offering an environmentally conscious route to valuable synthetic intermediates.