Borinic Acid Catalyzed Stereo- and Regioselective Couplings of Glycosyl Methanesulfonates
作者:Kyan A. D’Angelo、Mark S. Taylor
DOI:10.1021/jacs.6b06943
日期:2016.8.31
catalyst, room temperature). The borinic acid catalyst not only influences site-selectivity via activation of 1,2- or 1,3-diol motifs, but also has a pronounced effect on the stereochemical outcome: 1,2-trans-linked disaccharides are obtained selectively in the absence of neighboring group participation. Reaction progress kinetic analysis was used to obtain insight into the mechanism of glycosylation, both
在二芳基硼酸催化剂存在下,糖基甲磺酸盐与部分保护的吡喃糖苷和呋喃糖苷受体进行区域和立体选择性偶联。甲磺酸酯供体由糖基半缩醛原位制备,并在温和、操作简单的条件下(胺碱、有机硼催化剂、室温)偶联。硼酸催化剂不仅通过 1,2- 或 1,3- 二醇基序的活化影响位点选择性,而且对立体化学结果有显着影响:在不存在的情况下选择性地获得 1,2-反式连接的二糖邻组参与。反应进程动力学分析用于深入了解糖基化机制,在催化剂存在和不存在的情况下,而甲磺酸酯异头物的相互转化率则由核磁共振交换光谱法 (EXSY) 确定。总之,结果表明,尽管未催化和催化反应产生相反的立体化学结果,但两者都通过缔合机制进行。