NMR-spektroskopische untersuchungen an deprotonierten iminen und hydrazonen

N,N-Dialkylhydrazones in Organic Synthesis. From Simple N,N-Dimethylhydrazones to Supported Chiral Auxiliaries

“…The known synthetically useful C-C bond forming reactions (Scheme 5) of R-metalated hydrazones include Michael-type additions (26), aldol-type reactions (27), R-alkylation (31), and Claisen-type acylations (32). 4 example, in the synthesis of R-branched aldehydes including intermediates in the epothilone synthesis, 96 R-branched acyclic and cyclic ketones, 2 dioxanones, 97 lactones, 98 and -keto esters.…”

1-Azaallylic Anions in Heterocyclic Chemistry

“…During the past few decades 1-azaallylic anions derived from hydrazones have been extensively studied by NMR, − X-ray, − and theoretical calculations, , disclosing their ability to act as synthetic equivalents of enolate ions. They proved to have a greater efficiency of anion formation, lack of side reaction products, stability for hydrolysis or oxygenation in the absence of O 2 , CO 2 , and H 2 O, and higher reactivity toward electrophiles such as halides, 2 H -azirines, and carbonyl compounds (vide infra).…”

Product Class 7: Imines

“…[356,357] Kinetic deprotonation of ketimines leads principally to lithium E-enamines, while the thermodynamically controlled process mainly leads to the lithium Z-enamines. [358,359] The final point, regiochemistry of deprotonation, has been carefully investigated in the case of deprotonation of imines derived from pentan-3one. [356] In most cases, the least substituted carbon atom is deprotonated; [352,360] however, upon alkylation of heptan-2-imine with benzyl chloride, significant amounts of the more substituted isomer are formed.…”