本项目将围绕Kdo寡糖合成新方法及其应用开展研究。包括三方面工作：1）在Kdo分子的5,7-位安装环状缩醛（酮）保护基，剩余4-和8-位分别用不同类型的保护基保护，获得一类既能高立体控制生成α-苷键又具有正交保护基性质的Kdo糖基供体；2）另一方面，基于氢键诱导策略，在Kdo糖基供体的5-、7-或者8-位安装参与基2-喹啉羰基（Quin），系统考察Quin取代位置和个数对供体糖苷化反应立体选择性的影响，并结合活化基种类、溶剂、温度等反应参数的摸索，发展出高立体选择性制备β-Kdo糖苷键的供体。3）将前述方法学研究所得结果应用于天然Kdo寡糖及其结构类似物的合成，完成若干α以及β构型且具有重要生物学功能的Kdo寡糖的组装。项目的研究意义是为广泛分布于细菌细胞壁的Kdo寡糖提供新的、通用的合成途径，促进糖化学生物学的发展，具有重要的学术及应用价值。

This project focuses on the development and the application of novel synthetic approaches to Kdo glycosides. Three aspects of studies are included: 1) the Kdo molecule will be equipped with a cyclic protecting group on the 5,7-positions and with different protecting groups on the 4- and 8-positons to gain a type of Kdo glycosyl donor with strong α-stereocontrolling capability and orthogonal protecting groups; 2) on the other hand, based on the H-bond activation strategy, the stereocontrolling effect of 2-quinolinecarbonyl (Quin) on the 5-, 7- and 8-positions of Kdo donor on the stereochemistry results of β-glycosylation will be investigated. 3) application of the developed α- and β-Kdo glycosyl donors to the synthesis of a variety of complex Kdo oligosaccharides with biological importance. The significance of the project is development of high stereoselective and versatile glycosyl donors for the synthesis of Kdo-containing carbohydrate which widely distribute in cell wall of bacteria with important biological functions.