Effect of Protecting Groups and Solvents in Anomeric O-Alkylation of Mannopyranose1
Effect of Protecting Groups and Solvents in Anomeric O-Alkylation of Mannopyranose1
复制标题
保护基团和溶剂对吡喃甘露糖异头O-烷基化的影响1
DOI：
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发表时间：
1995
期刊：
影响因子：
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通讯作者：
R. Schmidt
中科院分区：
文献类型：
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作者：
J. Tamura;R. Schmidt
以甘露糖衍生物和2，3-O-异亚丙基-1-O-三氟甲磺酰基-D-甘油（1）为烷基化试剂，研究了不同保护基的吡喃甘露糖异头O-烷基化反应。一般而言，在极性溶剂中获得比在非极性溶剂中更高的α/β比。在6-O-位的空间要求保护基和极性溶剂导致更高的产率。反应性的差异被解释为不同的复合物形成。基于这些结果，分别使用具有6-O-（对甲氧基苯基）二苯基甲基的甘露糖衍生物5和6以及半乳糖基三氟甲烷磺酸酯24或九氟丁烷磺酸酯（九氟丁磺酸酯）25作为烷基化试剂，合成了甘露吡喃糖基-α（1-4）吡喃葡萄糖苷26和27。
Abstract Anomeric O-alkylation of mannopyranoses with various protecting groups was investigated using mannose derivatives and 2,3-O-isopropylidene-l-O-trifluoro-methanesulfonyl-D-glycerol (1) as alkylating agent. Generally, in polar solvents higher α/β ratios were obtained than in nonpolar solvents. Sterically demanding protecting groups at the 6-O-position and polar solvents led to higher yields. Reactivity differences were explained by different complex formation. Based on these results mannopyranosyl-α(1-4) glucopyranosides 26 and 27 were synthesized using mannose derivatives 5 and 6 having a 6-O-(p-methoxyphenyl)diphenylmethyl group and galactosyl trifluoromethane-sulfonate 24 or nonafluorobutanesulfonate (nonaflate) 25, respectively, as alkylating agents.