Conversion of pyranose glycals to furanose derivatives: A new route to oligofuranosides
Conversion of pyranose glycals to furanose derivatives: A new route to oligofuranosides
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DOI：
10.1021/jo9815406
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发表时间：
1998-11-27
影响因子：
3.6
通讯作者：
Lowary, TL
中科院分区：
文献类型：
--
作者：
D'Souza, FW;Cheshev, PE;Lowary, TL
乙酰化的吡喃糖醛酸通过方便的三步过程转化为受保护的呋喃糖还原糖。臭氧分解2,3,5-三- o -乙酰-葡萄糖或2,3,5-三- o -乙酰-半乳糖，然后用二甲基硫化物处理，然后水解，分别得到受保护的阿拉伯糖铀糖(6)和羟糖铀糖(7)衍生物。利用多种方法探索了这些半缩醛转化为低聚糖的方法。6或7的原位活化产生了适度产率和立体选择性的糖苷。从6和7中得到的四乙酸酯16和18的糖基化也得到了类似的结果。然而，同样由6和7衍生的硫代糖苷17和19被发现是有效的糖基供体，其产物收率很高，具有很高的立体选择性。该方法还用于合成一种双糖，其中一个残基含有均匀的C-13富集。
Acetylated pyranose glycals have been converted through a convenient three-step process into protected furanose reducing sugars. Ozonolysis of 2,3,5-tri-O-acetyl-glucal or 2,3,5-tri-O-acetyl-galactal, followed by treatment with dimethyl sulfide and then hydrolysis gave respectively protected arabinofuranose (6) and lyxofuranose (7) derivatives. Conversion of these hemiacetals to oligosaccharides was explored using a number of methods. Activation of 6 or 7 in situ afforded glycosides in modest yield and stereoselectivity. Glycosylation of tetraacetates 16 and 18, obtained from 6 and 7, gave similar results. However, thioglycosides 17 and 19, also derived from 6 and 7, were found to be effective glycosyl donors, producing products in good to excellent yields and with high stereoselectivities. The method was also used to synthesize a disaccharide in which one residue contained uniform C-13 enrichment.