Unsaturated carboxylic acid dienolates. Addition to substituted cyclohexanones. Inverted kinetic and thermodynamic stereoselectivities.

Abstract Addition of the lithium dienolate derived from crotonic acid to monosubstituted cyclohexanones occurs through the α and γ carbon atoms of the dienolate in the cold and on heating, respectively. For any regioselectivity, equatorial approach is found under kinetic conditions, but equilibration favours products from axial attack and selectivity may be inverted.