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Favorskii rearrangement of some α-Bromo-ketones

Nicholas J. Turro; Robert B. Gagosian; Christoffer Rappe; Leif Knutsson

Title:
Favorskii rearrangement of some α-Bromo-ketones
Author(s):
Turro, Nicholas J.
Gagosian, Robert B.
Rappe, Christoffer
Knutsson, Leif
Date:
Type:
Articles
Volume:
6
Permanent URL:
Book/Journal Title:
Journal of the Chemical Society D: Chemical Communications
Abstract:
The base-induced rearrangement of α-halogenoketones to give carboxylic acid derivatives (Favorskii rearrangements) occurs by at least two mechanisms. The stereochemistry, and structure of many Favorskii products can be explained in terms of a cyclopropanone intermediate. However, a "benzylic-like" rearrangement appears to operate when the substrate ketone bears no α'-hydrogen, when the α'-hydrogen is relatively non-acidic, or when steric or strain factors inhibit cyclopropanone formation. In addition, the formation of a dipolar intermediate which may precede (or follow) cyclopropanone formation is supported by theoretical considerations, loss of stereospecificity upon rearrangement in polar solvents, the formation of α-substitution products as a side reaction, and the trapping of a possible Favorskii intermediate "dehydrohalogenate" to form a common intermediate leading to the same product.
Subject(s):
Chemistry
Publisher DOI:
http://dx.doi.org/10.1039/C29690000270
Item views:
761
Metadata:
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