Stereochemical Course of Deprotonation-Acylation of N-Boc- and N-Carbamoyl-2-cyano-6-methylpiperidines

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• 作者：Yuri Kotomori ; Michiko Sasaki ; Masatoshi Kawahata ; Kentaro Yamaguchi ; Kei Takeda
• 刊名：Journal of Organic Chemistry
• 出版年：2015
• 出版时间：November 6, 2015
• 年：2015
• 卷：80
• 期：21
• 页码：11013-11020
• 全文大小：501K
• ISSN：1520-6904

文摘

The stereochemical course of electrophilic substitution of 伪-nitrile metallocarbanions generated by deprotonation from N-Boc- and N-carbamoyl-2-cyano-6-methylpiperidines was investigated. Deprotonation in the presence of an electrophile taking advantage of the high acidity of 伪-nitrile protons allowed examination of the effects of a chelating group on the nitrogen atom, a countercation, and the reactivity of an electrophile on the steric course. Analyses of reactions using aroyl chlorides and methyl iodide revealed the following: (1) the substitution reactions basically proceed with retention of configuration, (2) the extent of an inversion product increases with decreasing chelating ability of the N-substituent and with increasing leaving ability (ionic character) of a countercation (Li, Na, K) of the anionic species, and (3) the use of a more reactive electrophile results in an increase of the retention product.