On the Structure and Reactivity of Lithium Diisopropylamide (LDA) in Hydrcarbon Solutions. Formation of Unsolvated Ketone, Ester, and Carboxamide Enolates

Article abstract of DOI:10.1021/jo00014a019

Enolizations of ketones, tert-butyl esters, and carboxamides by solvent-free lithium diisopropylamide (LDA) in hexane or toluene are described.Enolates are isolated as spectroscopically pure, white (often crystalline) solids.Solubilities of the enolates in hexane range from highly soluble to completely insoluble.Enolization of aldehydes, methyl esters, and acetone afford complex mixtures.Analysis of <6Li>LDA and <6Li,15N>LDA in hexane by 6Li and 15N NMR spectroscopy show evidence of an equilibrium mixture of at least three cyclic oligomers.