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Rearrangement reaction
organic reactions where the carbon skeleton of a molecule is rearranged to give a structural isomer of the original molecule / From Wikipedia, the free encyclopedia
A rearrangement reaction is an organic reaction where the carbon skeleton of a molecule is rearranged. The result is a structural isomer of the original molecule.[1] Often a substituent moves from one atom to another atom in the same molecule. In the example below, the substituent R moves from carbon atom 1 to carbon atom 2:
![General scheme rearrangement](http://upload.wikimedia.org/wikipedia/commons/thumb/d/da/General_scheme_rearrangement.svg/320px-General_scheme_rearrangement.svg.png)
![]() | This article uses too much jargon, which needs explaining or simplifying. (January 2024) |
Intermolecular rearrangements also take place.
Sometimes chemists draw diagrams with arrows that show how electrons are transferred between bonds during a rearrangement reaction. Many organic chemistry text books have such diagrams. But they do not tell the full story of the reaction mechanism. The actual mechanism of a rearrangement with an alkyl group moving is for the group to slide smoothly along a bond, not ionic bond-breaking and forming. One example of this is the Wagner-Meerwein rearrangement:
In pericyclic reactions, the orbital interactions are important. The reactions can not be explained by a series of simple discrete electron transfers. The curved arrows showing a sequence of discrete electron transfers can give the same result as a rearrangement reaction. Yet, the diagrams are not necessarily realistic. In allylic rearrangement, the reaction is ionic.
Three important rearrangement reactions are 1,2-rearrangements, pericyclic reactions and olefin metathesis.