如何解决Favorskii重排与酮多卤代反应机理中烯醇化的矛盾  

How to Resolve Contradictory Enolization in Mechanisms of Favorskii Rearrangement and Polyhalogenation of Ketones

作　　者：许家喜 麻远[2] XU Jia-Xi;MA Yuan(College of Chemistry,Beijing University of Chemical Technology,Beijing 100029,China;Department of Chemistry,Tsinghua University,Beijing 100084,China)

机构地区：[1]北京化工大学化学学院,北京100029 [2]清华大学化学系,北京100084

出　　处：《化学教育（中英文）》2023年第4期103-105,共3页Chinese Journal of Chemical Education

基　　金：有机化学本科育人团队项目;有机化学和中级有机化学一流课程建设项目。

摘　　要：酮的多元卤代和α-卤代酮的Favorskii重排都是醛酮教学的重要内容,且都是在碱性条件下烯醇化后发生的。但是,前者是在含有卤素一侧烯醇化,而后者却是在不含卤素一侧烯醇化。这种烯醇化的“随意性”常引起学生困惑,甚至认为此2处的烯醇化是“矛盾”的。通过分析卤代酮烯醇化的可逆性和Favorskii重排的不可逆性合理地解释了Favorskii重排中烯醇化的合理性,化解了教学中的这一“矛盾”。Polyhalogenantion of ketones and the Favorskii rearrangement ofα-haloalkyl ketones are important reactions in the teaching chapter of aldehydes and ketones and both of them occur under basic conditions after enolization.However,the former enolizes in the halogenatedα-carbon atom,the later does in the non-halogenatedα-carbon atom.These enolizations“at random”usually make students confusing.They are thought to be contradictory by students.This article rationally explains the rationality of the enolization in the Favorskii rearrangement and resolves the“contradiction”in teaching through analyses of the reversibility in the enolization ofα-haloalkyl ketones and the irreversibility of the Favorskii rearrangement.

关 键 词：酮 卤代 烯醇负离子 Favorskii重排 卤代酮 

分 类 号：O621.25-4[理学—有机化学] G642[理学—化学]