- Jacobsen rearrangement
The Jacobsen rearrangement is a
chemical reaction, commonly described as the migration of an alkylgroup in a sulfonic acidderived from a polyalkyl- or polyhalobenzene:
The exact reaction mechanism is not completely clear, but evidence indicates that the rearrangement occurs intermolecularly and that the migrating group is transferred to a polyalkylbenzene, not to the sulfonic acid (
sulfonationonly takes place "after" migration). The intermolecular mechanism is partially illustrated by the side products found in the following example:
Furthermore, the reaction is limited to benzene rings with at least four
substituents (alkyl and/or halogengroups). The sulfo group is easily removed, so the Jacobsen rearrangement can also be considered as a rearrangement of polyalkylbenzenes. It was Herzig who described this type of rearrangementfor the first time in 1881using polyhalogenated benzenesulfonic acids, but the reaction took the name of the German chemistOscar Jacobsen, who described the rearrangement of polyalkylbenzene derivatives in 1886.
* Herzig. "
Ber." 14 (1881) 1205
* O Jacobsen. "
Ber." 19 (1886) 1209
* L I Smith. "Organic Reactions I: The Jacobsen Reaction" (Wiley, 1942)
* M B Smith, J March. "March's Advanced Organic Chemistry" (Wiley, 2001) (ISBN 0-471-58589-0)
* W Pötsch. "Lexikon bedeutender Chemiker" (VEB Bibliographisches Institut Leipzig, 1989) (ISBN 3817110553
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