Total Synthesis of Woodrosin I—Part 1: Preparation of the Building Blocks and Evaluation of the Glycosylation Strategy
作者:Alois Fürstner、Fabien Jeanjean、Patrick Razon、Conny Wirtz、Richard Mynott
DOI:10.1002/chem.200390025
日期:2003.1.3
19 into disaccharide 22 on treatment with the orthogonally protected glycosyl donor 15. The trichloroacetimidate method is also used for the formation of the second synthon represented by disaccharide 38. A model study shows that the assembly of the pentasaccharidic perimeter of 1 depends critically on the phasing of the glycosylation events between fragments 22, 38 and the rhamnosyl donor 27 due to
概述了木质素I(1)的总合成所需的三个结构单元的制备,这是一种带有大环内酯环的复杂树脂糖苷,该大环内酯环跨越其寡糖骨架的五个糖中的四个。关键步骤包括将对戊二酸锌对映体选择性地钛催化添加到5-己烯醛中,将所得醇18与葡萄糖衍生的三氯乙酰亚胺酸酯7进行糖基化,以及在用正交保护的糖基处理后进一步将所得产物19精制为二糖22。供体15。三氯乙酰亚氨酸盐的方法也用于形成以二糖38表示的第二个合成子。模型研究表明,五糖周长为1的组装主要取决于片段22之间糖基化事件的阶段,38和鼠李糖基供体27由于产品中的严重空间位阻。特别值得注意的发现是,在不保护相邻的2'-OH功能的情况下,二醇22可以在3'-OH基团上高选择性地被糖基化。