AskDefine | Define rearrangement

Dictionary Definition

rearrangement n : changing an arrangement

User Contributed Dictionary

English

Noun

  1. The process of rearranging.
  2. A rearrangement reaction.

Extensive Definition

A rearrangement reaction is a broad class of organic reactions where the carbon skeleton of a molecule is rearranged to give a structural isomer of the original molecule . 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:
Intermolecular rearrangements also take place.
A rearrangement is not well represented by simple and discrete electron transfers (represented by curly arrows in organic chemistry texts). The actual mechanism of alkyl groups moving, as in Wagner-Meerwein rearrangement, probably involves transfer of the moving alkyl group fluidly along a bond, not ionic bond-breaking and forming. In pericyclic reactions, explanation by orbital interactions give a better picture than simple discrete electron transfers. It is, nevertheless, possible to draw the curly arrows for a sequence of discrete electron transfers that give the same result as a rearrangement reaction, although these are not necessarily realistic.
Some key rearrangement reactions:

References

rearrangement in Arabic: تفاعل إعادة ترتيب
rearrangement in German: Umlagerung
rearrangement in Japanese: 転位反応
rearrangement in Portuguese: Reação de transposição
rearrangement in Finnish: Toisiintuminen
rearrangement in Chinese: 重排反应
Privacy Policy, About Us, Terms and Conditions, Contact Us
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2
Material from Wikipedia, Wiktionary, Dict
Valid HTML 4.01 Strict, Valid CSS Level 2.1