Glycosylation under Thermodynamic Control: Synthesis of the Di- and the Hexasaccharide Fragments of the O-SP ofVibrio Cholerae O:1 Serotype Ogawa from Fully Functionalized Building Blocks
作者:Roberto Adamo、Pavol Kováč
DOI:10.1002/ejoc.200600851
日期:2007.2
The known 5-(methoxycarbonyl)pentyl α-glycoside of the hexasaccharide of the O-SP of Vibrio cholerae O:1, serotype Ogawa 31 was newly prepared from side-chain-equipped disaccharide building blocks. The intermediate tetrasaccharide 25 was prepared from the disaccharide glycosyl acceptor 11 and the (12)-linked disaccharide thioglycoside glycosyl donor 8, having a (non-participating) saccharide moiety
霍乱弧菌 O:1、血清型 Ogawa 31 的 O-SP 六糖的已知 5-(甲氧基羰基)戊基 α-糖苷是从配备侧链的二糖结构单元中新制备的。中间体四糖 25 由二糖糖基受体 11 和 (12) 连接的二糖硫糖苷糖基供体 8 制备,在下游末端的 C-2 处具有(非参与)糖部分。当以常规方式进行时(在室温或低于 0 °C 的温度下),在没有嵌合辅助的情况下进行的 11 糖基化显示出较差的立体选择性,但通过热力学控制可以显着改善 1,2-反式糖苷键的形成。这种针对 31 的综合策略比逐步方法更有效,后者基于