ALKENE OXIDATION CATALYZED BY OXOVANADIUM-SCHIFF BASE COMPLEXES

Abstract

This research focuses on the development of allylic oxidation system using VO(salophen) catalyst. Cyclohexene was employed as a model substrate. Both amount of catalyst and amount of oxidant are essential in promoting the reaction. Utilizing this catalyst in combination with tert-butyl hydroperoxide in acetonitrile at reflux or hydrogen peroxide at room temperature for 4 hours, this catalytic system disclosed the unique characteristics to furnish allylic alcohol as a major product together with allylic ketone as a minor. No sign of epoxide was formed. Other substrates such as α-pinene, limonene, methyl oleate, 1-methylcyclohexene and 1-dodecene could be transformed into their oxidized products in moderate to high yield. The use of this catalytic system with hydrogen peroxide, the terminal double bond of α-methyl styrene was oxidatively cleaved to form oxidized products in moderate yield. This developed allylic oxidation reaction was believed to undergo via a free radical process.