Role of hydrogen migration in the mechanism of acetic acid elimination from MH+ ions of acetates on chemical ionization and collision-induced dissociation

被引：0

作者：

Kuzmenkov, I ^{[1
]}

Etinger, A ^{[1
]}

Mandelbaum, A ^{[1
]}

机构：

[1] Technion Israel Inst Technol, Dept Chem, IL-32000 Haifa, Israel

来源：

JOURNAL OF MASS SPECTROMETRY | 1999年 / 34卷 / 08期

关键词：

hydrogen transfer; 1,2-hydride shift; stereospecific fragmentation; chemical ionization; collision-induced dissociation; acid elimination; acetates; anchimeric assistance; deuterium isotope effect;

D O I：

10.1002/(SICI)1096-9888(199908)34:8<797::AID-JMS834>3.0.CO;2-X

中图分类号：

Q5 [生物化学];

学科分类号：

071010 ; 081704 ;

摘要：

The elimination of acetic acid from the MH+ ions of acetates of stereoisomeric 2-methyl-1-cyclohexanols and 1-hydroxy-trans-decalins exhibits a significant degree of stereospecificity under isobutane chemical ionization and collision-induced dissociation (CID) conditions, resulting in more abundant [MH - AcOH](+) ions in the cis-isomers 4c and 5tc than in their trans-counterparts 4t and 5tt, These findings suggest the involvement of a 1,2-hydride shift from the beta- to the alpha-position in the course of the acetic acid elimination from the MH+ ions of the above cis-acetates, resulting in tertiary carbocation structures. The proposed mechanism of the elimination is supported by a considerable deuterium isotope effect detected in beta-deuterium-labeled cis-2-methyl-1-acetoxycyclohexane and by a CID study of the structures of the [MH - AcOH](+) ions obtained from cis- and trans-1,2-diacetoxycyclohexanes. Copyright (C) 1999 John Wiley & Sons, Ltd.

引用

页码：797 / 803

页数：7