Stereochemical Course of Deprotonation-Acylation of N-Boc- and N-Carbamoyl-2-cyano-6-methylpiperidines
Stereochemical Course of Deprotonation-Acylation of N-Boc- and N-Carbamoyl-2-cyano-6-methylpiperidines
复制标题
N-Boc-和N-氨基甲酰基-2-氰基-6-甲基哌啶的去质子化-酰化立体化学过程
DOI：
10.1021/acs.joc.5b02178
复制
发表时间：
2015
期刊：
影响因子：
--
通讯作者：
Kei Takeda
中科院分区：
文献类型：
--
作者：
Yuri Kotomori;Michiko Sasaki;Masatoshi Kawahata;Kentaro Yamaguchi;Kei Takeda
研究了由N-Boc-和N-氨基甲酰基-2-氰基-6-甲基哌啶去质子化产生的α-腈金属碳负离子的亲电取代的立体化学过程。在亲电子试剂存在下，利用 α-腈质子的高酸性进行去质子化，可以检查螯合基团对氮原子、抗衡阳离子以及亲电子试剂对空间过程的反应性的影响。使用芳酰氯和甲基碘的反应分析揭示了以下内容：（1）取代反应基本上在构型保留的情况下进行，（2）反转产物的程度随着N-取代基的螯合能力的降低和阴离子物质的抗衡阳离子（Li，Na，K）的离去能力（离子特征）的增加而增加，以及（3）使用更具反应性的亲电子试剂结果 保留产物的增加。
The stereochemical course of electrophilic substitution of α-nitrile metallocarbanions generated by deprotonation fromN-Boc- andN-carbamoyl-2-cyano-6-methylpiperidines was investigated. Deprotonation in the presence of an electrophile taking advantage of the high acidity of α-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 theN-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.