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Updated: Jul 8, 2026

Preparation of a Corannulene-functionalized Hexahelicene by Copper(I)-catalyzed Alkyne-azide Cycloaddition of Nonplanar Polyaromatic Units
Published on: September 18, 2016
Reactions in the conjugated 'ene-ene-yne' manifold: five-membered ring fragmentation and ring formation via
Laura D Shirtcliff1, Sean P McClintock, Michael M Haley
1Department of Chemistry, University of Oregon, Eugene, Oregon 97403-1253, USA.
Abstract:
The fragmentation of a 5-membered heteroaromatic ring to afford a conjugated ene-ene-yne skeleton, and the corresponding reverse process, cyclization of the hetero-ene-ene-yne motif to generate a variety of heterocyclic systems, are the subject of this review. These synthetically useful reactions, which proceed through a coarctate/pseudocoarctate mechanistic pathway, are unique in that they involve the generation of either a carbene or nitrene intermediate, and provide access to hard to obtain heterocyclic or ene-ene-yne structures. While fragmentation of heteroaromatic rings containing a exocyclic carbene or nitrene has been well documented in the literature for over 40 years, the use of hetero-ene-ene-yne precursors to synthesize heterocycles is a relatively new approach that is generating much interest in the literature. This review highlights both the synthetic and mechanistic aspects of these unique reactions.
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