Regio/Stereoselective Glycosylation of Diol and Polyol Acceptors in Efficient Synthesis of Neu5Ac-α-2,3-LacNPhth Trisaccharide
作者:Ying Zhang、Fu-Long Zhao、Tao Luo、Zhichao Pei、Hai Dong
DOI:10.1002/asia.201801486
日期:2019.1.4
was developed. First, the regio/stereoselective glycosylation between glycoside donors and glucoNPhth diol acceptors was investigated. It was found that the regioselectivity depends not only on the steric hindrance of the C2‐NPhth group and the C6‐OH protecting group of the glucosamine acceptors, but also on the leaving group and protecting group of the glycoside donors. Under optimized conditions, LacNPhth
开发了Neu5Ac-α-2,3-LacNPhth三糖衍生物的简便方法。首先,研究了糖苷供体和葡萄糖NPhth二醇受体之间的区域/立体选择性糖基化。发现区域选择性不仅取决于葡糖胺受体的C2-NPhth基团和C6-OH保护基的空间位阻,还取决于糖苷供体的离去基团和保护基。在优化条件下,LacNPhth衍生物在高达92%的产率通过全乙酰-α-D-吡喃半乳糖三氯之间的区域选择性/立体选择性糖基化合成p -甲氧基苯基6- ö -叔-butyldiphenylsilyl -2-脱氧-2-苯二甲酰亚-β- d-吡喃葡萄糖苷,避免形成糖基化原酸酯和异头糖苷配基。然后,将LacNPhth衍生物脱酰基,然后通过TBDPS保护在伯位置上,以形成LacNPhth多元醇受体。最后,通过LacNPhth多元醇受体与亚磷酸唾液酸基酯供体之间的区域/立体选择性糖基化反应,以48%的产率合成了Neu5Ac-α-2,3-La