Iron-catalyzed epoxidation of olefins using hydrogen peroxide

Abstract

A practical method of olefin epoxidation was developed by combining FeCl₃·6H₂O and 1-methylimidazole in acetone using H₂O₂ as the terminal oxidant. This system showed very good reactivity toward epoxidation of both terminal and substituted alkenes. The use of tridentate and tetradentate amine-bis(phenolate) ligands as additives was also examined. Modest improvement in selectivity was achieved if a bulky tridentate ligand was used. Generally, however, the simple catalyst system involving ferric chloride, 1-methylimidazole and dilute H₂O₂ in acetone proved most successful in achieving good to excellent yields of epoxide products for a number of substrates, including aromatic and aliphatic alkenes.