Oxidation of Imines to Nitrones by the Permanganate Ion

Article abstract of DOI:10.1021/jo00262a029

A series of imines have been oxidized to nitrones in reasonable yields with the permanganate ion under phase-transfer conditions.The influence of the amount of permanganate, solvents, phase-transfer catalysts, and acidity of the aqueous phase on the reaction course have been investigated.It has been found that the presence of water is necessary for the formation of the nitrone.The best phase-transfer catalysts are quaternary ammonium salts with long aliphatic carbon chains.The mechanism for the permanganate oxidation of imines to nitrones is discussed from a frontier orbital point of view.It is suggested that the reaction proceeds via an interaction of the oxygen ligands in the permanganate ion to carbon and nitrogen in the imine.The electronic and geometrical structures of the permanganate-imine complex are discussed.