Alkylation de quelques composés carbonylés par des groupes tertiaires. Utilisation de la réaction de friedel-crafts dans la synthèse d'ésters

t-Alkylation of carboxylic esters via their ketene alkyl trimethylsilyl acetals by the Friedal-Crafts reaction allows the synthesis of new highly hindered compounds. A new route using sodium amide in dimethoxyethane, for the preparation of trimethylsilylenol ethers of ketones, is described. The α-t-butylation of these compounds permits the synthesis of new crowded pentasubstituted ketones. The limits as well as the performance of the method have been studied.