α- vs Ortho-Lithiation of N-Alkylarylaziridines: Probing the Role of the Nitrogen Inversion Process
α- vs Ortho-Lithiation of N-Alkylarylaziridines: Probing the Role of the Nitrogen Inversion Process
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DOI：
10.1021/jo8016549
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发表时间：
2008-12-05
影响因子：
3.6
通讯作者：
Musio, Biagia
中科院分区：
文献类型：
--
作者：
Affortunato, Francesco;Florio, Saverio;Musio, Biagia
单苯基和二苯基氮杂环丙烷的锂化反应已被详细研究，试图了解为什么前者只进行或主要是邻位锂化，而后者只在α-位锂化。有证据表明，排除了α-锂化的可能性，观察到的二苯基氮杂环丙烷，是在邻位到α-易位现象的结果，从而证实了直接的α-去质子化过程。氮丙啶氮孤对的作用已被认为是：氮丙啶氮的动态以及复杂的诱导邻近效应似乎是负责所观察到的区域选择性在monophenyl和diphenylaziridines。结果表明，通过调节反式-1-烷基-2-甲基-3-苯基氮杂环丙烷锂化的反应条件，可以以高区域选择性生成α-和/或邻位锂化的氮杂环丙烷，其可以通过亲电捕获立体选择性官能化。二苯基氮杂环丙烷的区域选择性邻位官能化可以通过卤素-或锡-锂交换和通过双氘代氮杂环丙烷的去质子化来实现。
The lithiation reaction of monophenyl- and diphenylaziridines has been investigated in detail in an effort to understand why the former undergo exclusively or mainly ortho-lithiation while the latter are lithiated exclusively at the alpha-position. Evidence is reported that ruled Out the possibility that the alpha-lithiation, observed for the diphenylaziridines, is the result of in ortho- to alpha-translocation phenomenon, thus substantiating a direct alpha-deprotonation process. The role of the aziridine nitrogen lone-pair has been considered: dynamics at the aziridine nitrogen as well as complex-induced proximity effects seem to be responsible for the observed regioselectivity in both monophenyl and diphenylaziridines. It turns Out that, by tuning the reaction conditions for the lithiation of trans-1-alkyl-2-methyl-3-phenylaziridines, it is possible to generate with high regioselectivity alpha- and/or ortho-lithiated aziridines, which can be stereoselectively functionalized by electrophilic trapping. A regioselective ortho-functionalization of diphenylaziridines is made possible by halogen- or tin-lithium exchange and by deprotonation of bis-deuterated aziridines.