Jacobsen reaction

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The Jacobsen reaction is a name reaction from the field of organic chemistry. Initial studies of this reaction were published by Josef Herzig as early as 1881 . However, the reaction bears the name of Oscar Jacobsen (1840-1889), who in 1886 carried out the reaction for the first time with alkyl-substituted benzenes.

Jacobsen reaction example 1

The Jacobsen reaction describes the sulfonation of at least four times substituted benzene . Alkyl groups ( methyl and ethyl ) and halogens ( iodine , chlorine and bromine ) are possible as substituents . The alkyl groups always move in such a way that they are closer to each other in the product:

Jacobsen reaction example 2

Reaction mechanism

The reaction mechanism of the Jacobsen reaction has not been conclusively clarified.

use

By desulfonating the product of the Jacobsen reaction again, the reaction can be used to rearrange polysubstituted benzenes.

Jacobsen reaction as rearrangement

Individual evidence

  1. J. Herzig: On the action of sulfuric acid on mono-di- and tribromobenzene . In: Monthly magazine for chemistry . 2, No. 1, 1881, pp. 192-199. doi : 10.1007 / BF01516504 .
  2. ^ O. Jacobsen: About the action of sulfuric acid on durol and about the third tetramethylbenzene . In: Reports of the German Chemical Society . 19, No. 1, 1886, pp. 1209-1217. doi : 10.1002 / cber.188601901274 .
  3. a b March, J. 1985 : Advanced Organic Chemistry: Reactions, Mechanisms and Structures . 3rd edition, New York: Wiley, ISBN 0-471-85472-7 .
  4. ^ H. Suzuki: On the Jacobsen Reaction. IV. Character and Reaction Mechanism . In: Bulletin of the Chemical Society of Japan . 36, No. 12, 1963, pp. 1642-1650. doi : 10.1246 / bcsj.36.1642 .