大学化学 >> 2020, Vol. 35 >> Issue (7): 1-7.doi: 10.3866/PKU.DXHX201912076

所属专题: 有机化学课程与实验教学

今日化学 上一篇    下一篇

半联胺重排机理

许家喜()   

  • 收稿日期:2019-12-30 录用日期:2020-01-28 发布日期:2020-02-24
  • 通讯作者: 许家喜 E-mail:jxxu@mail.buct.edu.cn
  • 基金资助:
    有机化学和中级有机化学一流课程建设项目

Mechanism of Semidine Rearrangements

Jiaxi Xu()   

  • Received:2019-12-30 Accepted:2020-01-28 Published:2020-02-24
  • Contact: Jiaxi Xu E-mail:jxxu@mail.buct.edu.cn

摘要:

半联胺通常是NN’-二芳基肼在酸性条件下发生联苯胺重排反应时的副产物,包括邻半联胺和对半联胺。在某些情况下,如取代芳基的NN’-二芳基肼重排的主要产物为邻半联胺和对半联胺。关于半联胺重排反应的机理,曾提出过π络合物过渡态机理、环己二烯正离子中间体机理和氯离子桥链的双阳离子型自由基对中间体机理,但通过动力学同位素效应、理论计算和实验结合研究确定该重排反应是构型翻转的N[1,3]σ迁移反应为关键步骤的周环反应。本文介绍了半联苯胺重排反应机理的研究历程及其代表性的实例。

关键词: σ迁移, 重排, N[1, 3]σ迁移, 半联胺, 二芳基肼, 构型翻转

Abstract:

Semidines, including ortho-semidines and para-semidines, are generally byproducts in the benzidine rearrangements of N, N'-diarylhydrazines under acidic conditions. Under certain cases, for instance, N, N'-diarylhydrazines with substituted aryl substituents would give o- and p-semidines as major products. The π complex mechanism, and mechanisms involving cyclohexadiene cation intermediates and chloride-bridge-linked dication diradical pairs for the formation of semidines were proposed. However, by referring the data of kinetic isotope effect studies, theoretical and experimental investigations suggest that semidine rearrangements are sigmatropic shifts of pericyclic reactions with configuration-inverted N[1, 3] sigmatropic shift as a key step. Mechanistic investigations and examples of semidine rearrangements are reviewed in this paper.

Key words: Sigmmatropic shift, Rearrangement, N[1, 3] sigmmatropic shift, Semidine, Diarylhydrazine, Configuration inversion

MSC2000: 

  • G64