title: Unexpected formation of a [4]radialene and dendralenes by addition of tetracyanoethylene to a tetraaryl[5]cumulene.
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.
authors.affiliation: 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.
authors.forename: Johanna A
authors.initials: JA
authors.lastname: Januszewski
authors.forename: Frank
authors.initials: F
authors.lastname: Hampel
authors.forename: Christian
authors.initials: C
authors.lastname: Neiss
authors.forename: Andreas
authors.initials: A
authors.lastname: Görling
authors.forename: Rik R
authors.initials: RR
authors.lastname: Tykwinski
keywords: TCNE; cumulenes; cycloaddition; dendralenes; radialenes