The Ireland ester enolate Claisen rearrangement gives rise to 2-trisubstituted alkenes due to heteroatom-enforced control over the conformation of the transition state. An oxygen-bearing functional group at the tertiary carbinol center, which can coordinate to the enolate metal via a seven-membered chelated transition state, provides the control element to explain the selectivity. a $-Disubstituted unsaturated carboxylic acids are also formed with high ...
