Jacobsen重排反应（Jacobsen rearrangement）

多烷基苯、卤代多烷基苯或多卤代苯在硫酸中烷基或卤原子的移位作用。

此反应一般可以分为两种类型：分子内的基团迁移，以及一个或多个原子团从一个分子转移到另一个分子的分子间迁移。在许多情况中两种类型的移位同时发生。 此反应的重要特点为烷基移位到近位。

重排反应的难易程度取决于连在苯环上的原子团性质和数目。如果仅有烷基存在，则只有四和五烷基衍生物能发生重排。磺酸取代的苯衍生物很容易发生脱磺化，因此这个反应可用于由非近位的取代基制备重要的近位取代物。

The Jacobsen rearrangement is a chemical reaction, commonly described as the migration of an alkyl group in a sulfonic acid derived 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 (sulfonation only takes place after migration). The intermolecular mechanism is partially illustrated by the side products found in the following example: