Metal-catalysed organic photoreactions. Photoreactions of 3,5-dimethylisoxazole with and without catalytic assistance by copper(II) salts

Abstract

Although 3,5-disubstituted isoxazoles afforded products of reactions involving solvent participation when irradiated in alcohols, they gave products of reductive ring-cleavage when irradiated in acetonitrile in the presence of triethylamine. A similar reductive ring cleavage was the main reaction path when these isoxazoles were irradiated in alcohols in the presence of copper(II) salts. A reaction scheme involving exciplex formation is proposed for the reduction.