Umpolung Reactivity in the Stereoselective Synthesis of S-Linked 2-Deoxyglycosides
作者:Kedar N. Baryal、Danyang Zhu、Xiaohua Li、Jianglong Zhu
DOI:10.1002/anie.201301682
日期:2013.7.29
Take control! An unprecedented sulfenylation of stereochemically defined 2‐deoxyglycosyl lithium species with asymmetric sugar‐derived disulfide acceptors enabled the stereoselective synthesis of both α‐ and β‐S‐linked 2‐deoxyoligosaccharides. Reductive lithiation of 2‐deoxyglycosyl phenylsulfides at −78 °C provides predominantly axial glycosyl lithium species, which upon warming isomerize to predominantly
控制住!立体化学定义的2-脱氧糖基锂物种与不对称糖衍生的二硫键受体的前所未有的亚磺酰化作用,使得立体选择性合成α-和β-S-连接的2-脱氧寡糖成为可能。在−78°C下2-脱氧糖基苯基硫化物的还原锂化作用主要提供了轴向糖基锂物质,该物质在升温时异构化为主要为赤道的锂物质(请参见方案)。