Quenching tertiary amides

Tertiary amides bearing epoxide and other labile moieties can be converted to the corresponding ketones (400a and 400b) in good yields, by treatment with alkyl- or aryllithiums followed by the usual quenching with a proton (equation 108). Furthermore, if the quenching is done with a peracid the amide is transformed to an ester (401, equation 109). Both processes leave the epoxy function unscathed. ... 

Birch reduction of pyrrole carboxylic esters and tertiary amides gives dihydro-derivatives the presence of an electron-withdrawing gronp on the nitrogen serves both to remove the acidic iV-hydrogen and also to rednce the electron density on the ring. Quenching the immediate reduced species - an enolate - with an alkyl halide produces alkylated dihydropyrroles. ... 

This polarimetric method was made even more general by utilizing chiral HPLC techniques. The L-UNCAwas dissolved in the solvent at a concentration of 0.33 M at 20 °C. The tertiary amine (1.5 equiv) was added at time zero. The solution was allowed to stand for an experimentally determined delay time, during which the only process that can occur was epimerization, since there is no nucleophile present. The delay time was determined after carrying out several experiments with different delay times and chosen so as to fall within or just after the first half-life for racemization. At the end of the delay period, benzylamine was added. Benzylamine is a very powerful nucleophile that reacts virtually instantly (regardless of the type of activation) with the resulting mixture of l- and d-UNCAs to form the benzyl amides and quench the epimerization process. Thus, a snapshot of the ratio of l/d activated intermediates at the instant of benzylamine addition was obtained by measurement of the l/d ratio of the benzyl amide products. 

Ammonio- and phosphoniohexafluorocyclobutanide ylides 11, prepared from pcrfluorocy-clobutene and tertiary amines or phosphanes, are soluble in a wide range of (even nonpolar) organic solvents and transfer fluoride, and therefore can be used as an easily soluble source of fluoride anions. Although they contain no ionic fluoride they react with fluoride anion acceptors such as silicon derivatives with elimination of thermodynamically favored fluoro-trimethylsilane to produce carbanions which can be quenched with suitable electrophiles. The reaction proceeds upon slightly heating the reactants in tetrahydrofuran or dimethylform-amide solution. 

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