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The Claisen rearrangement is a powerful carbon–carbon bond-forming chemical reaction discovered by Rainer Ludwig Claisen. [1] The heating of an allyl vinyl ether will initiate a [3,3]-sigmatropic rearrangement to give a γ,δ-unsaturated carbonyl, driven by exergonically favored carbonyl CO bond formation Δ(Δ f H) = −327 kcal/mol (−1,370 kJ/mol).
[11] [12] [13] This rearrangement is a useful carbon-carbon bond-forming reaction. An example of Claisen rearrangement is the [3,3] rearrangement of an allyl vinyl ether, which upon heating yields a γ,δ-unsaturated carbonyl. The formation of a carbonyl group makes this reaction, unlike other sigmatropic rearrangements, inherently irreversible.
The mechanism for this transformation is formally a Claisen rearrangement, supported by the kinetic and isotopic data reported by Knowles, et al. [7] Reaction catalyzed by chorismate mutase. E. coli and Yeast chorismate mutase have a limited sequence homology, but their active sites contain similar residues. The active site of the Yeast ...
The reaction is known as the Claisen reaction and was described by Claisen for the first time in 1890. Discovered the thermally induced rearrangement of allyl phenyl ether in 1912. He details its reaction mechanism in his last scientific publication (1925). In his honor, the reaction has been named the Claisen rearrangement.
In organic chemistry, 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. [1] Often a substituent moves from one atom to another atom in the same molecule, hence these reactions are usually intramolecular.
In [1,j]-sigmatropic rearrangements if j + 1 = 4n, then supra/antara is thermally allowed, and if j + 1 = 4n + 2, then supra/supra or antara/antara is thermally allowed. [20] The other prevalent class of sigmatropic rearrangements are [3,3], notably the Cope and Claisen rearrangements. Here, the constructive interactions must be between the ...
The Ireland–Claisen rearrangement is a chemical reaction of an allylic ester with strong base to give an γ,δ-unsaturated carboxylic acid. [1] [2] [3]
Johnson–Claisen rearrangement [ edit ] The Johnson–Claisen rearrangement is the reaction of an allylic alcohol with an ortho ester containing a deprotonatable alpha carbon (e.g. triethyl orthoacetate ) to give a γ,δ-unsaturated ester .