Aerobic Baeyer–Villiger Oxidation of Cyclic Ketones over Metalloporphyrins Bridged Periodic Mesoporous Organosilica

Highly ordered Metal-tetrakis(carboxyphenyl)porphyrin (Metal = Fe, Cu, Sn) bridged periodic mesoporous organosilicas (M-TCPP-PMO) with high surface area were synthesized from corresponding M-tetrakis(carboxyphenyl)porphyrin-silsesquioxanes as tetra-silanes by the sol–gel method. The Baeyer–Villiger oxidation of ketones to the corresponding esters using molecular oxygen as an oxidant over M-TCPP-PMOs was investigated. Fe-TCPP-PMO was found to exhibit higher catalytic activity than Cu-TCPP-PMO and Sn-TCPP-PMO. The high catalytic activity is attributed to the high-valent Fe-porphyrin on the wall of mesoporous silica along with cyclohexanone, which results in successful completion of the oxygen transfer step and generation of ε-caprolactone. The obtained results demonstrate that Fe-TCPP-PMO is a promising and efficient catalyst for the Baeyer–Villiger oxidation of ketones to esters using O2 as the oxidant.