On the regioselectivity of the protease subtilisin towards the acylation of enantiomeric pairs of benzyl and naphthyl glycopyranosides. Part 2
摘要:
Subtilisin-catalyzed esterification of several enantiomeric benzyl and naphthyl glycopyranosides has been investigated. The D-sugar derivatives were all good substrates and subtilisin regioselectivity was similar with all the compounds tested, the 3-OH being acylated predominantly. On the other hand, most of the L-glycopyranosides were transformed during longer reaction times with a lower regioselectivity, the 2-OH being preferentially but not exclusively acylated. (C) 1999 Elsevier Science Ltd. All rights reserved.
On the regioselectivity of the protease subtilisin towards the acylation of enantiomeric pairs of benzyl and naphthyl glycopyranosides. Part 2
摘要:
Subtilisin-catalyzed esterification of several enantiomeric benzyl and naphthyl glycopyranosides has been investigated. The D-sugar derivatives were all good substrates and subtilisin regioselectivity was similar with all the compounds tested, the 3-OH being acylated predominantly. On the other hand, most of the L-glycopyranosides were transformed during longer reaction times with a lower regioselectivity, the 2-OH being preferentially but not exclusively acylated. (C) 1999 Elsevier Science Ltd. All rights reserved.
Selective Axial-to-Equatorial Epimerization of Carbohydrates
作者:Hayden M. Carder、Yong Wang、Alison E. Wendlandt
DOI:10.1021/jacs.2c04743
日期:2022.7.6
Radical-mediated transformations have emerged as powerful methods for the synthesis of rare and unnatural branched, deoxygenated, and isomeric sugars. Here, we describe a radical-mediated axial-to-equatorial alcohol epimerization method to transform abundant glycans into rare isomers. The method delivers highly predictable and selective reaction outcomes that are complementary to other sugar isomerization
自由基介导的转化已成为合成稀有和非天然支链、脱氧和异构糖的有效方法。在这里,我们描述了一种自由基介导的轴向到赤道醇差向异构化方法,可将丰富的聚糖转化为稀有异构体。该方法提供高度可预测和选择性的反应结果,与其他糖异构化方法互补。异构体相互转化的合成效用通过方便的聚糖合成展示,包括一步糖多样化。机理研究表明,位点选择性和非对映选择性都是通过赤道位置的 α-羟基 C-H 键的高选择性 H 原子提取来实现的。