Ireland-Claisen Rearrangement

This Gentle Variant Of The Claisen Rearrangement Employs The Allyl Ester Of A Carboxylic Acid Instead Of An Allyl Vinyl Ether. The Ester Is Converted To Its Silyl-stabilized Enolate (silyl Ketene Acetal), Which Rearranges At Temperatures Below 100 °C.

The Immediate Product Of The Rearrangement, A Carboxylic Acid Silyl Ester, Cannot Be Isolated And Is Hydrolyzed During Workup. The Ireland-Claisen Rearrangement Thus Offers Ready Access To Chain-extended Carboxylic Acids.

Mechanism Of The Ireland-Claisen Rearrangement

As With The Claisen Rearrangement, The Ireland Modification Also Proceeds With A High Degree Of Stereoselectivity:

An Advantage Of The Ireland-Claisen Rearrangement Is The Option Of Controlling The Enolate Geometry Through The Judicious Choice Of Solvent:

Recent Literature

Catalytic Diastereoselective Reductive Claisen Rearrangement
S. P. Miller, J. P. Morken, Org. Lett., 2002, 4, 2743-2745.