3-BocNH-ABNO-catalyzed Aerobic Oxidation Of Alcohols At Room Temperature

Selective oxidation of alcohols to aldehydes or ketones is one of the most classical and important organic chemical reactions.The reaction is widely used in fine chemical industry,pharmaceutical synthesis,flavor and fragrance industries?The oxidation of tertiary alcohols is often accompanied by rearrangement reaction and elimination reaction,which is of little significance in practical application?.In order to achieve this transformation,stoichiometric oxidants are needed in traditional oxidation methods.More toxic and harmful wastes were produced in the reaction process.There are many shortcomings in safety and environmental friendliness.Oxygen has attracted more and more attention because of its abundant sources,low price and cleanliness.From the point of economy and environmental protection,it is undoubtedly the best choice to use oxygen as terminal oxidant in oxidation reaction.In recent years,more and more catalysts such as stable nitroxyl radicals?TEMPO,AZADOs,ABNO?have been used in selective catalytic oxidation.Therefore,it is still the focus of people to find a synthetic route with high efficiency,green and high selectivity.On the basis of literature and previous research work of our group,we successfully developed a transition metal-free catalyzed aerobic oxidation system and applied it to selective oxidation reaction.Part 1.Benzylamine hydrochloride,25%glutaraldehyde aqueous solution,acetone dicarboxylic acid and sodium acetate were used as raw materials to synthesize 3-?tert-butoxycarbonylamino?-9-azabicyclo[3.3.1]nonane N-oxyl?3-BocNH-ABNO?and 3-acetamide-9-azabicyclo[3.3.1]nonane N-oxyl?3-AcNH-ABNO?in six steps.9-azabicyclic[3.3.1]nonane-nitroxy radical?ABNO?was synthesized from the same starting material in four steps.Part 2.3-BocNH-ABNO was chosen as catalyst and 3-BocNH-ABNO/NaNO₂/AcOH system was developed for aerobic oxidation of alcohols.Benzyl alcohol was selected as the model substrate.The optimum reaction conditions were obtained through optimization:room temperature?25 ^oC?,AcOH as solvent,8 mol%NaNO₂ as co-catalyst and oxygen as terminal oxidant.The optimized catalytic system was suitable for the oxidation of most benzyl alcohols?including heteroaromatic benzyl alcohol?and aromatic secondary alcohols with conversion of more than 99%.For aliphatic alcohols,high conversion rate could be obtained under the conditions that the amount of NaNO₂was increased from 8 mol%to 10 mol%and the amount of 3-BocNH-ABNO was increased from 3 mol%to 5 mol%.In this dissertation,the synthetic route of 3-BocNH-ABNO was explored and the catalytic oxidation system of 3-BocNH-ABNO/NaNO₂/AcOH was constructed.This system was applied to the aerobic oxidation of alcohols.The system had the advantages of less catalyst consumption,wide substrate scope,high reaction activity and no use of transitnion metal.Meanwhile,oxygen was selected as environmentally friendly green oxidant.At the same time,the whole reaction process was free of toxic and harmful solvents and simple to operate.It would have potential application value.