ISSN:
0009-2940
Keywords:
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Description / Table of Contents:
Reactions of Iminium Salts with Organolithium CompoundsThe nucleophilic addition of n-butyllithium at -60°C to iminium salts 1, 5, 12 derived from aldehydes and cyclohexanone leads to the tertiary amines 2, 6, 11. Less reactive are derivatives of cyclopentanone (14), very poor results are obtained with iminium salts derived from acetone (7, 9). In these cases, as examined by reactions of derivatives of acetophenone, benzylmethyl and isopropylmethylketone 16, 22, 27, enamines are formed by deprotonation in α-position to the iminium carbon. N,N-Dimethyl(diphenylmethylene)ammonium iodide (31) as a derivative of benzophenone reacts with n-butyllithium to form an adduct 30. With phenyllithium, and with arylmagnesium halides, however, deprotonation of a methyl group on iminium nitrogen leads to formation of N,N,N′-trimethyl-1,1-trimethyl-1,1-diphenylethanediamine (32).
Notes:
Die nucleophile Addition von n-Butyllithium bei -60°C an Iminiumsalze 1, 5, 12, die von Aldehyden oder Cyclohexanon abgeleitet sind, führt in guten Ausbeuten zu den tertiären Aminen 2, 6, 11. Derivate des Cyclopentanons (14) reagieren schlechter und sehr schlecht solche des Acetons (7, 9). Versuche mit Abkömmlingen des Acetophenons, Benzylmethylketons und Isopropylmethylketons 16, 22, 27 lehren, daß der Grund dafür die Bildung von Enaminen durch Deprotonierung zum Iminiumkohlenstoff α-ständiger C—H-Bindungen ist. Das von Benzophenon abgeleitet N,N-Dimethyl(diphenylmethylen)ammonium-jodid (31) gibt mit n-Butyllithium das Additionsprodukt 30, während Phenyllithium in gleicher Weise wie Arylmagnesiumhalogenide unter Deprotonierung einer Methylgruppe am Iminiumstickstoff N,N,N′-Trimethyl-1,1-diphenyläthandiamin (32) bildet.
Additional Material:
1 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19751081119
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