Metal-Free Aerobic Oxidation of Alcohols

Significance

A metal-free catalytic aerobic oxidation of alcohols is reported. 5-Fluoro-2-azaadamantane N-oxyl (1) was found to be particularly suited to catalyze the oxidation of various alcohols to the corresponding carbonyl compounds. In the presence of 1 (1 mol%) and NaNO₂ (10 mol%), the products were obtained in high yields within short reaction times using air as the stoichiometric oxidant. The authors found that under the reaction conditions 1 reacts with NaNO₂ to form the oxoammonium ion, which turned out to be the catalytically active species. Consequently the corresponding oxoammonium nitrate 2 (5 mol%) can likewise well be applied as catalyst, giving comparable results without the need for other additives.