IUPAC > Gold Book > alphabetical index > L > leaving group
icon

IndexesDownload


leaving group

An atom or group (charged or uncharged) that becomes detached from an atom in what is considered to be the residual or main part of the substrate in a specified reaction. For example, in the heterolytic solvolysis of benzyl bromide in acetic acid:
L03493-1
the leaving group is Br; in the reaction:
L03493-2
the leaving group is NMe3 ; in the electrophilic nitration of benzene, it is H+. The term has meaning only in relation to a specified reaction. The leaving group is not, in general, the same as the substituent group present in the substrate (e.g. bromo and trimethylammonio in the substrates of the first two examples above.) A slightly different usage of the term prevails in the (non-mechanistic) naming of transformations, where the actual substituent group present in the substrate (and also in the product) is referred to as the leaving group.
Source:
PAC, 1994, 66, 1077 (Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)) on page 1134
InChI=1/C8H10S/c1-9-7-8-5-3-2-4-6-8/h2-6H,7H2,1H3
OFQPKKGMNWASPN-UHFFFAOYAM
InChI=1/C3H9N/c1-4(2)3/h1-3H3
GETQZCLCWQTVFV-UHFFFAOYAA
InChI=1/C7H7Br/c8-6-7-4-2-1-3-5-7/h1-5H,6H2
AGEZXYOZHKGVCM-UHFFFAOYAM
InChI=1/C2H4O2/c1-2(3)4/h1H3,(H,3,4)/f/h3H
QTBSBXVTEAMEQO-TULZNQERCK
InChI=1/C9H10O2/c1-8(10)11-7-9-5-3-2-4-6-9/h2-6H,7H2,1H3
QUKGYYKBILRGFE-UHFFFAOYAD
InChI=1/BrH/h1H
CPELXLSAUQHCOX-UHFFFAOYAZ
Interactive Link Maps
First LevelSecond LevelThird Level
GraphGraphGraph
Cite as:
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997). XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8. doi:10.1351/goldbook.
Last update: 2014-02-24; version: 2.3.3.
DOI of this term: doi:10.1351/goldbook.L03493.
Original PDF version: http://www.iupac.org/goldbook/L03493.pdf. The PDF version is out of date and is provided for reference purposes only. For some entries, the PDF version may be unavailable.
Current PDF version | Version for print | History of this term
picture