作者:Lisa M. Doyle、Shane O’Sullivan、Claudia Di Salvo、Michelle McKinney、Patrick McArdle、Paul V. Murphy
DOI:10.1021/acs.orglett.7b02760
日期:2017.11.3
Glycosyl thiols are widely used in stereoselective S-glycoside synthesis. Their epimerization from 1,2-trans to 1,2-cis thiols (e.g., equatorial to axial epimerization in thioglucopyranose) was attained using TiCl4, while SnCl4 promoted their axial-to-equatorial epimerization. The method included application for stereoselective β-d-manno- and β-l-rhamnopyranosyl thiol formation. Complex formation explains
糖基硫醇广泛用于立体选择性S-糖苷合成中。使用TiCl 4获得了它们从1,2-反式到1,2-顺式硫醇的差向异构化(例如,在硫代吡喃葡萄糖中赤道到轴向差向异构),而SnCl 4促进了它们的轴向-赤道差向异构。该方法包括用于立体选择性β- d-甘露聚糖和β- 1- rhamnopyranosyl硫醇形成的应用。当使用SnCl 4时,络合物的形成解释了赤道偏爱,而TiCl 4可以通过1,3-氧杂硫杂环戊烷的形成使平衡向1,2-顺式硫醇转移。