Acta Chim. Sinica ›› 2015, Vol. 73 ›› Issue (10): 1002-1006.DOI: 10.6023/A15050355 Previous Articles     Next Articles

Communication

可再生型高价碘试剂亚碘酰二内酯在高效醇氧化中的应用研究

宋爱茹a,b, 张弛a   

  1. a 南开大学元素有机化学国家重点实验室 天津化学化工协同创新中心 天津 300071;
    b 天津师范大学 天津市水资源与水环境重点实验室 天津 300387
  • 投稿日期:2015-05-24 发布日期:2015-07-17
  • 通讯作者: 张弛 E-mail:zhangchi@nankai.edu.cn
  • 基金资助:

    项目受国家自然科学基金(Nos.21172110,21472094,21421062)资助.

Iodosodilactone as a Recyclable Oxidant for Efficient Oxidation of Alcohols to Carbonyl Compounds

Song Airua,b, Zhang Chia   

  1. a State Key Laboratory of Elemento-Organic Chemistry, Collaborative Innovation Center of Chemical Science and Engineering, Nankai University, Tianjin 300071, China;
    b Tianjin Key Laboratory of Water Resources and Environment, Tianjin Normal University, Tianjin 300387
  • Received:2015-05-24 Published:2015-07-17
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Nos. 21172110, 21472094, 21421062).

Various primary alcohols can be selectively oxidized to the corresponding aldehydes in excellent yields by iodosodilactone in the presence of a nitroxyl radical catalyst 2,2,6,6-tetramethylpiperidin-1-yloxy (TEMPO) and stoichiometric amount of 4-dimethylaminopyridine (DMAP) in chloroform under reflux. On the other hand, secondary alcohols can be oxidized to the corresponding ketones efficiently with a structurally less hindered nitroxyl radical catalyst 1-methyl-2-azaadamantane N-oxyl (1-Me-AZADO) instead of TEMPO. The mechanism of this alcohol oxidation reaction has been proposed. First, a zwitterion intermediate A was formed after the ligand exchange around the iodine(III) atom; then A would oxidize the nitroxyl radical TEMPO to its oxoammonium salt C, which was responsible for the oxidation of alcohols and was reduced to the hydroxylamine D. Finally, D was oxidized by A to C to re-start the next alcohol oxidation cycle. Note that both DMAP and 2-iodo-isophthalic acid (the reduced form of iodosodilactone) can be recovered easily after reaction. A representative procedure for the alcohols oxidation and the recovery of DMAP and the regeneration of iodosodilactone are as follows: Iodosodilactone (217 mg, 0.75 mmol) was added to a solution of an alcohol (0.5 mmol), TEMPO (7 mg, 0.04 mmol) and DMAP (73 mg, 0.6 mmol) in CHCl3 (5 mL) at room temperature, the reaction mixture was refluxed until the alcohol was no longer detected (TLC). Then the mixture was cooled to room temperature, filtered and washed with CH2Cl2 (60 mL). The filtrate was washed sequentially with 1 mol/L HCl, 10% Na2CO3, and brine. Then the organic layer was dried over anhydrous Na2SO4 and concentrated in vacuum. Flash column chromatography was applied to give the corresponding pure carbonyl compound. The residue collected during the previous filtration step was stirred in aqueous HCl (5%, 50 mL) and then filtered. The obtained aqueous phase was neutralized to pH 8~9 by saturated aqueous NaOH solution to release DMAP, then DMAP was extracted with CH2Cl2 (30 mL×3), the organic layer was dried over anhydrous Na2SO4 and concentrated in vacuum to afford the recovered DMAP in 90% yield. At last, the treatment of the combination of the aqueous phase after CH2Cl2 extraction and the residue collected in the latest filtration with concentrated HCl (2 mL) and aqueous NaClO solution (5.84%, 4 mL) led to the regeneration of oxidant iodosodilactone in 93% yield.

Key words: iodosodilactone, recyclable, hypervalent iodine reagent, alcohol oxidation, nitroxyl radical