Allylic oxidation of alkenes catalyzed by metal stearate complexes

Abstract

This research focuses on the development of a catalytic system using metal stearate for allylic oxidation. Cyclohexene was employed as a model substrate. Both types of catalyst and amount of TBHP are essential in promoting the reaction. With the use of TBHP as an oxidant in combination with chromium (III) stearate catalyst at 70 degree Celsius for 24 hours afforded an alpha, Beta-unsaturated carbonyl compound in high yield with good selectitivy. Moreover, the allylic oxidation worked well in non-polar aprotic solvent, such as isooctane, toluene, benzene, acetonitrile and pyridine. Under optimized conditions, alkenes were oxidized to the corresponding alpha, Beta-unsaturated ketone in good to excellent yiel. Moreover, the allylic oxidation of alpha-pinene, 1-methylcyclohexene, alpha-ionone, Belta-ionone, Belta-ionone and isophorone could be fruitfully accomplished in moderate to high yield with excellent selectivity to the corresponding alpha, Beta-unsaturated carbonyl compounds. This developed allylic oxidation reaction was believed to undergo via a free radical process.