RADICAL VERSUS OXENOID OXYGEN INSERTION MECHANISM IN THE OXIDATION OFALKANES AND ALCOHOLS BY AROMATIC PERACIDS - NEW SYNTHETIC DEVELOPMENTS

Evidences concerning a novel free-radical mechanism for the oxidation of alkanes by aromatic peracids are reported. The mechanism involves h ydrogen abstraction from the OH group of peracids by an aroyloxyl radi cal; the acylperoxyl radical thus generated is responsible for the sel ective oxidation. The reaction is affected by the presence of oxygen a nd it is inhibited by TEMPO and by solvents forming hydrogen bonds wit h peracids. A more simple and effective synthetic procedure has been d eveloped, on the basis of the autoxidation of aliphatic and aromatic a ldehydes in the presence of alkanes. It is also shown that the previou sly reported inertness of alcohols toward peracids must be ascribed to solvent effects, due to the formation of hydrogen bonds; in suitable solvents alcohol oxidation smoothly occurs.