Milieux hyperbasiques: préparation et alkylation de carbanions en α d'amides N,N-disubstitués. Application à la synthèse de la d,l-pipéritone

The anions α to N,N-disubstituted amides can be conveniently prepared by treatment with very powerful bases, "activated dialkylamides" in HMPT. These anions may react with various electrophiles especially with halogenated compounds. The use of functional halides (chloro or bromo compounds) affords functional amides. Lithiated amides are very useful intermediates in organic synthesis because they give regiospecific alkyl ketones by reacting with organo lithium compounds. In this way, we succeeded in obtaining the 1,5-diketone which was cyclised by intramolecular aldolization into d,l-piperitone.