Development of novel aerobic oxidation method using N-hydroxyphthalimide as catalyst

Novel methods for the oxidation of alkanes with molecular oxygen using a radical catalyst, N-hydroxyphthalimide (NHPI), have been developed. Thus, a variety of alkanes such as cyclohexane, adamantane and toluene which are very difficult to be oxidized with molecular oxygen by conventional methods could be converted into the corresponding alcohols and/or carbonyl compounds in high yields. The application of the same methodology to adamantane with CO/air led to adamantanecarboxylic acid through radical carbonylation in fair yield. The reaction of benzyl ethers with NO in the presence of NHPI afforded the corresponding aldehydes in good yields. The present method provides a new class of aerobic oxidaion which is reffered to as radical-catalyzed autoxidation.