Alkylation de quelques composés carbonylés par des groupes tertiaires. Utilisation de la réaction de friedel-crafts dans la synthèse d'ésters
作者:Claude Lion、Jacques-Emile Dubois
DOI:10.1016/s0040-4020(01)92017-4
日期:1981.1
t-Alkylation of carboxylic esters via their ketene alkyltrimethylsilyl 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
4-dimethyl-2-oxazolines, 4, after hydrolysis of the intermediate enamine. Alkylation of the latter also permits the synthesis of α,α,α-trisubstituted ketones. α,α-Disubstituted ketones have been prepared by addition of organometallic reagents to 4,4-dimethyl-2-oxazolinium salts, 6. The efficiency of this method has been compared to that of other currently used methods.