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.](https://cdn.name-reaction.com/assets/_reaction_images/_png/ireland-claisen-rearrangement-s-7618c08e72872030672d0421cadd3cd7.png)
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
References:
| 1. |
Ireland, R. E.; Mueller, R. H.
J. Am. Chem. Soc.
1972,
94,
5897–5898.
|
| 2. |
Ireland, R. E.; Willard, A. K.
Tetrahedron Letters
1975,
16,
3975–3978.
|
| 3. |
Ireland, R. E.; Mueller, R. H.; Willard, A. K.
J. Am. Chem. Soc.
1976,
98,
2868–2877.
|