Selective Oxidation of Unprotected Carbohydrates to Aldehyde Analogues by Using TEMPO Salts
作者:Tony Breton、George Bashiardes、Jean-Michel Léger、Kouakou B. Kokoh
DOI:10.1002/ejoc.200600914
日期:2007.4
ide and methyl-α-D-galactopyranoside) was selectively converted into the corresponding aldehyde in the form of acetals by using TEMPO+ BF4– (2,2,6,6-tetramethylpiperidine-1-oxoammonium tetrafluoroborate) in organic medium with 2,6-lutidine as the base. Indeed, organic anhydrous conditions prevent over oxidation of the alcohol group to the carboxylate form. The resulting compounds, methyl-α-D-glucohexodialdo-1
通过使用 TEMPO+ BF4–,基本上未受保护的碳水化合物(甲基-α-D-吡喃甘露糖苷、甲基-α-D-吡喃葡萄糖苷和甲基-α-D-吡喃半乳糖苷)的伯醇功能被选择性地转化为缩醛形式的相应醛。 (2,2,6,6-四甲基哌啶-1-四氟硼酸氧铵) 在以 2,6-二甲基吡啶为碱的有机介质中。事实上,有机无水条件可防止醇基过度氧化为羧酸盐形式。所得化合物,甲基-α-D-glucohexodialdo-1,5-pyranoside 和甲基-α-D-manohexodialdo-1,5-pyranoside 用 NMR 和质谱法表征。此外,将在 TEMPO 电化学介导系统中获得的结果与纯 TEMPO+ BF4– 系统的结果进行比较,但由于反应速度非常慢,电化学条件下的产率较低。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)