Protecting group free glycosylation: one-pot stereocontrolled access to 1,2-<i>trans</i> glycosides and (1→6)-linked disaccharides of 2-acetamido sugars
作者:Xin Qiu、Anna L. Garden、Antony J. Fairbanks
DOI:10.1039/d2sc00222a
日期:——
and acid catalysed reaction with an alcohol as solvent produces the corresponding 1,2-trans-glycosides in good yield. Alternatively, dissolution in an aprotic solvent system and acidic activation in the presence of an excess of an unprotected glycoside as a glycosyl acceptor, results in the stereoselective formation of the corresponding 1,2-trans linked disaccharides without any protecting group manipulations
未受保护的 2-乙酰氨基糖可以在水溶液中使用 2-氯-1,3-二甲基咪唑啉 (DMC) 和合适的碱直接转化为它们的恶唑啉。以醇为溶剂的冷冻干燥和酸催化反应以良好的收率产生相应的1,2-反式-糖苷。或者,在非质子溶剂系统中溶解并在存在过量未保护糖苷作为糖基受体的情况下进行酸性活化,导致立体选择性形成相应的1,2-反式连接的二糖,而无需任何保护基团操作。使用芳基糖苷作为受体的反应是完全区域选择性的,仅产生 (1→6)-连接的二糖。