糖基化
化学
立体选择性
葡萄糖醛酸盐
保护组
立体化学
组合化学
催化作用
生物化学
有机化学
烷基
作者
Lei Duan,Qin Nie,Yongxin Hu,Liming Wang,Ke Guo,Zhuan Zhou,Shengyuan Xu,Yuan-Hong Tu,Hui Liu,Thomas Hansen,Jiansong Sun,Qingju Zhang
标识
DOI:10.1002/anie.202306971
摘要
Herein, we described the first synthesis of the pentasaccharide and decasaccharide of the A. baumannii ATCC 17961 O-antigen for developing a synthetic carbohydrate-based vaccine against A. baumannii infection. The efficient synthesis of the rare sugar 2,3-diacetamido-glucuronate was achieved using our recently introduced organocatalytic glycosylation method. We found, for the first time, that long-range levulinoyl group participation via a hydrogen bond can result in a significantly improved β-selectivity in glycosylations. This solves the stereoselectivity problem of highly branched galactose acceptors. The proposed mechanism was supported by control experiments and DFT computations. Benefiting from the long-range levulinoyl group participation strategy, the pentasaccharide donor and acceptor were obtained via an efficient [2+1+2] one-pot glycosylation method and were used for the target decasaccharide synthesis.
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