Wohl-Ziegler reaction

The Wohl-Ziegler reaction [cite journal
title = Bromierung ungesättigter Verbindungen mit N-Brom-acetamid, ein Beitrag zur Lehre vom Verlauf chemischer Vorgänge
author = Alfred Wohl
journal = Berichte der deutschen chemischen Gesellschaft
volume = 52
issue =
pages = 51–63
year = 1919
url =
doi = 10.1002/cber.19190520109] [cite journal
title = Die Synthese des Cantharidins
author = Ziegler, K., G. Schenck, E. W. Krockow, A. Siebert, A. Wenz, H. Weber
journal = Justus Liebig's Annalen der Chemie
volume = 551
issue =
pages = 1–79
year = 1942
url =
doi = 10.1002/jlac.19425510102] is a chemical reaction that involves the allylic or benzylic bromination of hydrocarbons using an "N"-bromoimide and a radical initiator. [OrgSynth | author=Greenwood, F. L.; Kellert, M. D.; Sedlak, J. |year=1963 |title=4-bromo-2-heptene |collvol=4 |collvolpages=108 |prep=cv4p0108]

Best yields are achieved with "N"-bromosuccinimide in carbon tetrachloride solvent.

Several reviews have been published. [cite journal | author = C. Djerassi | title = Brominations with N-Bromosuccinimide and Related Compounds. The Wohl-Ziegler Reaction | year = 1948 | journal = Chem. Rev. | volume = 43 | issue = 2 | pages = 271–317 | doi = 10.1021/cr60135a004] [Horner, L.; Winkelman, E. M.; "Angew. Chem." 1959, "71", 349. (Review)]

In a typical setup a a stoichiometric amount of "N"-bromosuccinimide solution and a small quantity of initiator are added to a solution of the substrate in CCl₄, and the reaction mixture is stirred and heated to the boiling point. Initiation of the reaction is indicated by more vigorous boiling; sometimes the heat source may need to be removed. Once all "N"-bromosuccinimide (which is denser than the solvent) has been converted to succinimide (which floats on top) the reaction has finished.

References