Oxidation of alkanes with <i>m</i>-chloroperbenzoic acid catalyzed by iron(III) chloride and a polydentate amine

Tetradentate amine <i>N,N′</i>-bis(2-pyridylmethylene)-1,4-diaminodiphenyl ether (compound <b>1</b>) dramatically accelerates the oxidation of alkanes with MCPBA in acetonitrile catalyzed by FeCl₃, whereas <i>N,N′</i>-bis(2-pyrrolidinmethylene)-1,4-diaminodiphenyl ether (<b>2</b>) does not affect the reaction. The selectivity of the reaction in the presence of <b>1</b> is noticeably higher than that in its absence. On the basis of the kinetic study and selectivity parameters a mechanism has been proposed which includes the formation of a complex between a molecule of MCPBA and coordinated to ligand <b>1</b> iron ion. This complex decomposes to produce a Fe(II) derivative which is further oxidized by MCPBA to generate a (<b>1</b>•Fe=O)⁴⁺ species reacting with both alkane and acetonitrile. Finally, alkyl hydroperoxide is formed which partially decomposes to produce more stable corresponding alcohol and ketone (aldehyde).