Unexpected formation of a [4]radialene and dendralenes by addition of tetracyanoethylene to a tetraaryl[5]cumulene.

Angew Chem Int Ed Engl

Department für Chemie und Pharmazie & Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Henkestrasse 42, 91054 Erlangen (Germany) http://www.chemie.uni-erlangen.de/tykwinski.

Published: April 2014


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Article Abstract

The use of cumulenes in synthetic transformations offers the possibility to form structurally interesting and potentially useful conjugated molecules. The cycloaddition reaction of a tetraaryl[5]cumulene with the electron-deficient olefin tetracyanoethylene affords unusual products, including functionalized dendralenes and alkylidene cyclobutanes, as well as a symmetric [4]radialene that shows unique solvatochromism, with λ(max) values approaching the near-IR region. These carbon-rich products have been investigated spectroscopically and by X-ray crystallographic analysis (five structures). The cycloaddition reaction sequence has also been explored by mechanistic and theoretical studies. The obtained results clearly demonstrate the potential of [5]cumulenes to serve as precursors for unprecedented conjugated structures.

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http://dx.doi.org/10.1002/anie.201309355DOI Listing

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