How to Resolve Contradictory Enolization in Mechanisms of Favorskii Rearrangement and Polyhalogenation of Ketones
XU Jia-Xi1**, MA Yuan2
1. College of Chemistry, Beijing University of Chemical Technology, Beijing 100029, China; 2. Department of Chemistry, Tsinghua University, Beijing 100084, China
Abstract Polyhalogenantion of ketones and the Favorskii rearrangement of α-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 halogenated α-carbon atom, the later does in the non-halogenated α-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 of α-haloalkyl ketones and the irreversibility of the Favorskii rearrangement.
XU Jia-Xi, MA Yuan. How to Resolve Contradictory Enolization in Mechanisms of Favorskii Rearrangement and Polyhalogenation of Ketones[J]. Chinese Journal of Chemical Education, 2023, 44(4): 103-105.