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Updated: Apr 11, 2026

Preparation of a Corannulene-functionalized Hexahelicene by CopperI-catalyzed Alkyne-azide Cycloaddition of Nonplanar Polyaromatic Units
Published on: September 18, 2016
Unprecedented "off-pathway" [2+2] Cycloaddition-Retroelectrocyclization Reaction Between an Unsymmetric Alkyne and
Oscar Fernández-Vera1, Luca Sagresti2,3, Luis M Mateo1,4
1Departamento de Química Orgánica, Universidad Autónoma de Madrid, Campus de Cantoblanco, Madrid, 28049, Spain.
Abstract:
In recent years, the [2+2] cycloaddition-retroelectrocyclization (CA-RE) reaction between electron-rich alkynes and electron-deficient alkenes has emerged as one of the most effective synthetic routes to prepare a large variety of molecular and polymeric electron donor-acceptor systems. Besides its simplicity, fast rate, and high yield, this reaction may also display complete and predictable regioselectivity, as in the case when tetracyanoquinodimethane (TCNQ) is used in combination with unsymmetric, activated alkynes. Here, we report the first example of a [2+2] CA-RE reaction between TCNQ and an aniline-activated alkyne following an "inverted" regiochemistry, thus leading to the exclusive formation of an unexpected regioisomer in contrast to the expected one. A combined experimental and theoretical study helped us to unravel the peculiar reaction mechanism underlying the regioselectivity switching.
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