Mechanism
The Claisen rearrangement (and its variants) are exothermic (about 84 kJ/mol), concerted pericyclic reactions which according to the Woodward-Hoffmann rules show a suprafacial reaction pathway.
There are substantial solvent effects in the Claisen reactions. More polar solvents tend to accelerate the reaction to a greater extent. Hydrogen-bonding solvents gave the highest rate constants. For example, ethanol/water solvent mixtures give rate constants 10-fold higher than sulfolane.
Trivalent organoaluminium reagents, such as trimethylaluminium, have been shown to accelerate this reaction.
Read more about this topic: Claisen Rearrangement
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