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The Cope rearrangement is the prototypical example of a concerted sigmatropic rearrangement. It is classified as a [3,3]-sigmatropic rearrangement with the Woodward–Hoffmann symbol [π 2 s + σ 2 s + π 2 s] and is therefore thermally allowed.
The Cope rearrangement is an extensively studied organic reaction involving the [3,3] sigmatropic rearrangement of 1,5-dienes. [ 14 ] [ 15 ] [ 16 ] It was developed by Arthur C. Cope . For example, 3,4-dimethyl-1,5-hexadiene heated to 300 °C yields 2,6-octadiene.
The aza-Cope rearrangements are predicted by the Woodward-Hoffman rules to proceed suprafacially. However, while never explicitly studied, Overman and coworkers have hypothesized that, as with the base-catalyzed oxy-Cope rearrangement, the charged atom distorts the sigmatropic rearrangement from a purely concerted reaction mechanism (as expected in the Cope rearrangement), to one with partial ...
The reverse or retro-Cope elimination has been reported, in which an N,N-disubstituted hydroxylamine reacts with an alkene to form a tertiary N-oxide. [ 9 ] [ 10 ] The reaction is a form of hydroamination and can be extended to the use of unsubstituted hydroxylamine, in which case oximes are produced.
In organic chemistry, the oxy-Cope rearrangement is a chemical reaction.It involves reorganization of the skeleton of certain unsaturated alcohols. It is a variation of the Cope rearrangement in which 1,5-dien-3-ols are converted to unsaturated carbonyl compounds by a mechanism typical for such a [3,3]-sigmatropic rearrangement.
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Illustrative example of the cope rearrangement. Vector version of Image:3,3copeexpansion.JPG I made with Inkscape. Date: 20 June 2006 (original upload date) Source: Transferred from to Commons. Author: The original uploader was Marco Polo at English Wikipedia. Later versions were uploaded by Bkell at en.wikipedia. Permission (Reusing this file)
The divinylcyclopropane-cycloheptadiene rearrangement is an organic chemical transformation that involves the isomerization of a 1,2-divinylcyclopropane into a cycloheptadiene or -triene. It is conceptually related to the Cope rearrangement , but has the advantage of a strong thermodynamic driving force due to the release of ring strain.