Ireland-Claisen rearrangement

Also known as: Claisen-Ireland rearrangement

Schematic of the Ireland-Claisen rearrangement. Reagents: allyl ester, LDA, TMSCl, NaOH, water. Product: γ,δ-unsaturated carboxylic acid. Comments: Concerted [3,3]-sigmatropic rearrangement.

The Ireland-Claisen rearrangement is an organic reaction used to convert an allyl ester to a γ,δ-unsaturated carboxyl acid using LDA, TMSCl, and NaOH/H2O. The reaction begins with deprotonation of the α-hydrogen of the ester to form an enolate which then attacks TMSCl to stabilize the charge and produce LiCl salt. The two olefin groups are ideally positioned for a Claisen rearrangement, which results in the formation of a carbonyl group. Deprotection of the TMS group with base and protonation then results in the final carboxylic acid product.[1][2][3]


Mechanism of the Ireland-Claisen rearrangement.


Ireland, R. E.; Mueller, R. H. J. Am. Chem. Soc. 1972, 94, 5897–5898.
Ireland, R. E.; Willard, A. K. Tetrahedron Letters 1975, 16, 3975–3978.
Ireland, R. E.; Mueller, R. H.; Willard, A. K. J. Am. Chem. Soc. 1976, 98, 2868–2877.