α-和β-糖苷的水解。新的实验数据及反应途径建模

Hydrolysis of alpha- and beta-glycosides. New experimental data and modeling of reaction pathways.

作者信息

Deslongchamps Pierre, Li Shigui, Dory Yves L

机构信息

Département de Chimie, Institut de Pharmacologie, Université de Sherbooke, 3001, 12e Avenue Nord, Sherbrooke, Québec J1H 5N4, Canada.

出版信息

Org Lett. 2004 Feb 19;6(4):505-8. doi: 10.1021/ol036220+.

DOI:10.1021/ol036220+

PMID:14961609

Abstract

[reaction: see text] The cyclization of oxocarbenium ion conformers 6alpha and 6beta (from 11E and 11Z) gave only the beta-glycoside 1beta, and the addition of methanol to the oxocarbenium ion 3 yielded mainly the alpha-glycoside 1alpha with both experiments being carried out under kinetically controlled conditions. RHF/6.31G calculations reproduce well these experimental results and show that the endocyclic and the exocyclic C-O bond cleavage processes can compete in the hydrolysis of 1beta, whereas 1alpha gets hydrolyzed by exocyclic C-O bond cleavage only.

摘要

[反应：见正文] 氧鎓离子构象异构体6α和6β（来自11E和11Z）的环化仅生成β-糖苷1β，并且在动力学控制条件下进行的两个实验中，甲醇加成到氧鎓离子3上主要生成α-糖苷1α。RHF/6.31G计算很好地再现了这些实验结果，并表明在1β的水解中环内和环外C-O键断裂过程可以相互竞争，而1α仅通过环外C-O键断裂被水解。