INTRAMOLECULAR HYDROGEN-ATOM ABSTRACTION - THE BETA-OXYGEN EFFECT IN THE NORRISH TYPE-II PHOTOREACTION

被引：22

作者：

BRUNCKOVA, J ^{[1
]}

CRICH, D ^{[1
]}

机构：

[1] UNIV ILLINOIS,DEPT CHEM MC111,CHICAGO,IL 60607

来源：

TETRAHEDRON | 1995年 / 51卷 / 44期

基金：

美国国家科学基金会;

关键词：

HYDROGEN ATOM ABSTRACTION; NORRISH II REACTION; BETA-OXYGEN EFFECT; 1-ALKOXY-1-GLYCOSYL RADICALS; PHENACYL ETHERS;

D O I：

10.1016/0040-4020(95)00755-W

中图分类号：

O62 [有机化学];

学科分类号：

070303 ; 081704 ;

摘要：

The preparation of phenacyl glycosides of alpha- and beta-tetrabenzylglucopyranose of alpha-tetrabenzylmannopyranose. and of 2-hydroxytetrahydropyran is described. Photolysis of each compound through Pyrex results cleanly in lactone formation by the Norrish type II photocleavage. Competition experiments are described which demonstrate that both glucosyl anomers are consumed at the same rate in the course of the photolysis. Similar experiments establish that the phenacyl alpha-glucoside is marginally more reactive than the corresponding alpha-mannoside. The tetrahydropyran derivative is cleaved much more rapidly the carbohydrates. This effect is interpreted in terms destabilization of the polarized transition state for hydrogen atom abstraction by the beta-oxygen bonds in the carbohydrate series.

引用

页码：11945 / 11952

页数：8

共 39 条

[1] OXYGEN CARBON BETA-BOND EFFECTS IN RADICAL REACTIONS [J].