X-ray Crystal Structures of Lithium, Sodium, and Potassium Enolates of Pinacolone

Abstract

Reaction of 3,3-dimethyI-2-butanone (pinacolone) with alkali amide bases yields crystalline enolates. These compounds were subjected to single-crystal X-ray diffraction analysis. The lithiated enolate aggregates as an unsolvated hexamer, the sodium enolate aggregates as a tetramer solvated by unenolized ketone, and the potassium derivative aggregates as a hexamer solvated by THF. Comparison of the crystal structures with one another and with other alkali metal enolate structures reveals subtle differences. These structural differences may be useful for explaining reactivity differences and may have potential utility in organic synthesis. © 1986, American Chemical Society. All rights reserved.