Abronina Polina I, Fedina Ksenia G, Podvalnyy Nikita M, Zinin Alexander I, Chizhov Alexander O, Kondakov Nikolay N, Torgov Vladimir I, Kononov Leonid O
N.D. Zelinsky Institute of Organic Chemistry of the Russian Academy of Sciences, Leninsky prosp., 47, 119991 Moscow, Russian Federation.
N.D. Zelinsky Institute of Organic Chemistry of the Russian Academy of Sciences, Leninsky prosp., 47, 119991 Moscow, Russian Federation; Higher Chemical College of the Russian Academy of Sciences, Miusskaya pl. 9, 125047 Moscow, Russian Federation.
Carbohydr Res. 2014 Sep 19;396:25-36. doi: 10.1016/j.carres.2014.05.017. Epub 2014 Jun 5.
The influence of O-trifluoroacetyl (TFA) groups at different positions of thioglycoside glycosyl donors on stereoselectivity of α-arabinofuranosylation leading to corresponding disaccharides was studied. It was shown that TFA group in thioglycoside glycosyl donors, when combined with 2-O-(triisopropylsilyl) (TIPS) non-participating group, may be regarded as an electron-withdrawing protecting group that may enhance 1,2-cis-selectivity in arabinofuranosylation, the results strongly depending on the nature of glycosyl acceptor. The reactivities of the glycosyl donors were compared with those of a similar thioglycoside with O-pentafluoropropionyl groups and the known phenyl 3,5-O-(di-tert-butylsilylene)-1-thio-α-d-arabinofuranosides with 2-O-TIPS and 2-O-benzyl groups. The 'matching' in the donor-acceptor combination was found to be critical for achieving both high reactivity of glycosyl donor and β-stereoselectivity of arabinofuranosylation. The use of glycosyl donors with TFA and silyl protection may be useful in the realization of the benzyl-free approach to oligoarabinofuranosides with azido group in aglycon-convenient building blocks for the preparation of neoglycoconjugates.
研究了硫代糖苷糖基供体不同位置的O-三氟乙酰基（TFA）基团对导致相应二糖的α-阿拉伯呋喃糖基化立体选择性的影响。结果表明，硫代糖苷糖基供体中的TFA基团与2-O-（三异丙基甲硅烷基）（TIPS）非参与基团结合时，可被视为吸电子保护基团，其可增强阿拉伯呋喃糖基化中的1,2-顺式选择性，结果很大程度上取决于糖基受体的性质。将这些糖基供体的反应性与具有O-五氟丙酰基的类似硫代糖苷以及已知的具有2-O-TIPS和2-O-苄基的苯基3,5-O-（二叔丁基甲硅烷基）-1-硫代-α-D-阿拉伯呋喃糖苷的反应性进行了比较。发现供体-受体组合中的“匹配”对于实现糖基供体的高反应性和阿拉伯呋喃糖基化的β-立体选择性都至关重要。使用具有TFA和甲硅烷基保护的糖基供体可能有助于实现无苄基方法合成苷元中带有叠氮基的低聚阿拉伯呋喃糖苷，这是制备新糖缀合物的方便构建块。
