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Updated: Jul 14, 2026

A Two-Step Protocol for Umpolung Functionalization of Ketones Via Enolonium Species
Published on: August 16, 2018
An experimental and computational approach to defining structure/reactivity relationships for intramolecular addition
Shuangyi Wan1, Hakan Gunaydin, K N Houk
1Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, USA.
Abstract:
In this manuscript we report that oxidative cleavage reactions can be used to form oxocarbenium ions that react with pendent epoxides to form bicyclic epoxonium ions as an entry to the formation of cyclic oligoether compounds. Bicyclic epoxonium ion structure was shown to have a dramatic impact on the ratio of exo- to endo-cyclization reactions, with bicyclo[4.1.0] intermediates showing a strong preference for endo-closures and bicyclo[3.1.0] intermediates showing a preference for exo-closures. Computational studies on the structures and energetics of the transition states using the B3LYP/6-31G(d) method provide substantial insight into the origins of this selectivity.
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