Alcoylation des enolates de l'acetylacetate d'ethyle dans le dimethoxyethane. Reactivite des formes associee et dissociee

The alkylation of alkali metal and N⁺Bu₄ ethylacetoacetate énolates by means of ethyl iodide, bromide and tosylate has been studied in diméthoxyéthane, in order to measure the reactivity of the associated forms. C/O alkylation ratios, structures of O-alkylated products and rates of alkylation, have been determined. With ethyl tosylate, the amount of O-alkylated products does not increase in the generally observed order Li⁺ < Na⁺ < K⁺ < Cs⁺ but in the order Na⁺ < K⁺ < Li⁺ ≈ Cs⁺. Some aspects of the alkali ethylacetoacetate énolates reactivity in weakly polar medium such as DME are discussed.