Synthetic Routes toward Acidic Pentasaccharide Related to the <i>O</i>-Antigen of <i>E. coli</i> 120 Using One-Pot Sequential Glycosylation Reactions
作者:Mana Mohan Mukherjee、Rina Ghosh
DOI:10.1021/acs.joc.7b00561
日期:2017.6.2
Concise syntheses of the acidic pentasaccharide, related to the O-antigenic polysaccharide of Escherichia coli 120, as its p-methoxyphenyl glycoside, have been achieved using a one-pot sequential glycosylation technique. The glycosylations have been accomplished either by the activation of the thioglycosides using NIS in the presence of FeCl3 or by a preactivation by Ph2SO, TTBP, Tf2O, and the activation
已经使用一锅顺序糖基化技术实现了与大肠杆菌120的O-抗原多糖有关的酸性五糖的精确合成,作为其对甲氧基苯基糖苷。糖基化反应是通过在FeCl 3存在下使用NIS活化硫糖苷或通过Ph 2 SO,TTBP,Tf 2 O进行预活化,以及使用FeCl 3活化三氯乙酰亚氨酸酯来完成的。单独或TMSOTf。大部分中间步骤都是高产的,糖基化步骤的立体效果非常好。靶向五糖的合成已经通过三组分和四组分一锅顺序糖基化反应进行,并且在两种情况下,正交糖基化都是利用FeCl 3的催化活性进行的。已进行了后期的TEMPO介导的区域选择性氧化,以实现所需的糖醛酸基序。