Aerobic oxidative cleavage of cinnamaldehyde to benzaldehyde catalyzed by metalloporphyrins under mild conditions

Efficient oxidative cleavage of cinnamaldehyde to benzaldehyde catalyzed by metalloporphyrins in the presence of dioxygen has been developed. Manganese(III) meso-tetraphenylporphyrin chloride (MnTPPCl) showed excellent activity for the oxidation under mild conditions. Different influencing factors have been investigated, and 71% yield of benzaldehyde was obtained under the optimum conditions (60 °C, 3 h, toluene as solvent, molar ratio for cinnamaldehyde:MnTPPCl:isobutylaldehyde = 1:0.001:5). Moreover, a plausible mechanism including free radical process and high-valent intermediate (MnIVO) was proposed.