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Abnormal Claisen Rearrangement

Published Online: 15 SEP 2010

DOI: 10.1002/9780470638859.conrr001

Comprehensive Organic Name Reactions and Reagents

Comprehensive Organic Name Reactions and Reagents

How to Cite

2010. Abnormal Claisen Rearrangement. Comprehensive Organic Name Reactions and Reagents. 1:1–4.

Publication History

  1. Published Online: 15 SEP 2010

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Abstract

The first example of abnormal Claisen rearrangement was reported by Lauer and Filbert in 1936. In contrast to the regular Claisen rearrangement (σ migration), the abnormal Claisen rearrangement usually occurs for allyl aromatic ethers. A similar reaction also occurs for the thermal rearrangement of cyclopropyl ketones to homoallylic ketones. The abnormal Claisen rearrangement is believed to proceed via two consecutive processes, i.e., the normal ortho Claisen rearrangement of γ-alkylallyl aryl ether to an o-(α-alkylallyl) phenol and the isomerization of the resulting phenol. In general, this type of abnormal Claisen rearrangement does not occur smoothly, except when in the presence of Lewis acids FeCl3, even though other Lewis acids (e.g., HfCl4, GaCl3, and ZrCl4) have limited ability to accelerate such reaction. It is reported that the abnormal Claisen rearrangement can be prevented by the application of 1,1,1,3,3,3-hexamethyldisilazane and N,O bis(trimethylsilyl)acetamide.

Keywords:

  • Claisen rearrangement;
  • isomerization;
  • thermal rearrangement;
  • Lewis acids

Featured Compounds

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  1. 1 - 2
Compound 1
Molecular Weight:178.1846
Molecular Formula:C10H10O3
InChIKey:PVYWGBFXWQWRHH-UHFFFAOYSA-N
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Compound 2
Molecular Weight:178.1846
Molecular Formula:C10H10O3
InChIKey:DVWCHQMUBIKDHR-UHFFFAOYSA-N
View compound in article | Full details | Search for this compound

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