Yamago Shigeru, Yamada Takeshi, Ito Hiroki, Hara Osamu, Mino Yosuke, Yoshida Jun-ichi
Division of Molecular Materials Science, Graduate School of Science, Osaka City University, Japan.
Chemistry. 2005 Oct 21;11(21):6159-74. doi: 10.1002/chem.200500126.
A new method for constructing an oligosaccharide library composed of structurally defined oligosaccharides is presented based on an iterative glycosylation of selenoglycosides. Treatment of 2-acyl-protected selenoglycosides with bromine selectively generates beta-bromoglycosides, which serve as glycosyl cation equivalents in the oligosaccharide synthesis. Thus, the coupling of the bromoglycosides with another selenoglycoside affords the corresponding glycosylated selenoglycosides, which can be directly used to next glycosylation. The iteration of this sequence allows the synthesis of a variety of oligosaccharides including an elicitor active heptasaccharide. A characteristic feature of the iterative glycosylation is that glycosyl donors and acceptors with the same anomeric reactivity can be selectively coupled by activation of the glycosyl donor prior to coupling with the glycosyl acceptor. Therefore, same selenoglycosides can be used for both the glycosyl donors and the acceptors. This feature has been exemplified by a construction of an oligosaccharide library directed to elicitor-active oligosaccharides. The library composed of stereochemically defined oligoglucosides with considerable structural diversity can be constructed starting from simple selenoglycosides.
基于硒代糖苷的迭代糖基化反应，提出了一种构建由结构明确的寡糖组成的寡糖文库的新方法。用溴处理2-酰基保护的硒代糖苷可选择性地生成β-溴代糖苷，其在寡糖合成中作为糖基阳离子类似物。因此，溴代糖苷与另一种硒代糖苷的偶联可得到相应的糖基化硒代糖苷，其可直接用于下一步糖基化反应。该序列的迭代允许合成多种寡糖，包括具有激发子活性的七糖。迭代糖基化反应的一个特征是，具有相同异头反应性的糖基供体和受体可在与糖基受体偶联之前通过活化糖基供体而选择性地偶联。因此，相同的硒代糖苷可用于糖基供体和受体。这一特征已通过构建针对激发子活性寡糖的寡糖文库得到例证。从简单的硒代糖苷出发，可以构建由具有相当结构多样性的立体化学定义的寡葡糖苷组成的文库。
