Metalloporphyrin-mediated aerobic oxidation of hydrocarbons in cumene: Co-substrate specificity and mechanistic consideration

Abstract Selective aerobic oxidation of hydrocarbons by molecular oxygen to afford valuable oxygen-containing functional compounds is a key challenge in modern chemical industry. Herein, an efficient catalytic system including metalloporphyrins as ideal catalysts and cumene as a co-substrate was developed for the aerobic oxidation of hydrocarbons to afford products with high yields and excellent chemoselectivities. Notably, this biomimetic process was found to be similar to cytochrome P450 monooxygenase-catalyzed reactions according to Michaelis–Menten kinetics. Experimental results and in situ monitoring techniques including the kinetic study, in situ ultraviolet–visible spectroscopy, and in situ electron spin resonance spectroscopy indicated that in situ generated cumyl hydroperoxide acted as an actual oxidant. Its formation was possibly mediated by metalloporphyrins to generate numerous free-radical species, and the high-valent Mn IV –oxo π-cation radicals were regarded as active species in the aerobic oxidation. Consequently, both the co-substrate specificity and the possible reaction mechanism were systematically investigated based on the control experiments and results obtained from our previous studies.