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

Abstract

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.

Catalytic reduction of 1- and 2-bromooctanes by a dinickel(I) Schiff base complex containing two salen units electrogenerated at carbon cathodes in dimethylformamide

“…The dinickel(II) Schiff base complex (Ni 2 (II)L, 1) was obtained by mixing 100 mg of ligand in 10 mL of chloroform with stoichiometric amounts of nickel acetate in 10 mL of methanol. The products were characterized by NMR (Varian 400 MHz) and ESI-MS (Finnegan LCQ Classic) spectrometry: (a) for the ligand containing two salen units (L), 1 Preparation of N,N-dimethylnonanamide [16], N-methyl-Noctylformamide [17], N-methyl-N-nonylformamide [16], N,N,2-trimethyloctanamide [18], and 7,8-dimethyltetradecane [19] was accomplished according to reported procedures. The identity of each compound was confirmed with the aid of gas chromatography-mass spectrometry ( …”

Milieux hyperbasiques: préparation de carbanions en α d'amides N,N-disubstitués. Synthèse de β- et γ-hydroxyamides et de γ-butyrolactones

“…Nous avons rCalisC la mitallation des amides N,N-disubstituCs selon le mode optratoire dCja dCcrit (1). Le carbanion se forme aisCment sous l'action des amidures "activCsH que l'amide soit lintaire, ramifiC ou cyclique.…”

“…Nous avons vu que les carbanions, aisCment formis a basse tempirature, pouvaient Etre alkylis dans d'excellentes conditions grgce a la prCsence du HMPT (1).…”