title: Regioisomeric allene dimer formation by the reaction of tetraarylbutatrienes with tetracyanoethene.
abstract: The reaction of tetraarylbutatrienes (tetraaryl[3]cumulenes) with tetracyanoethene (TCNE), a strong electron-accepting molecule, at room temperature yielded novel four-membered ring compounds (head-to-tail unsymmetrically substituted diarylallene dimers) by [2 + 2] cycloaddition of the central C=C bond of the butatrienes. This reaction proceeded through a head-to-head symmetrically substituted diarylallene dimer intermediate. Unsymmetrical butatriene also formed a small amount of another head-to-tail dimer. Although the allene dimer is stable in nonpolar solvents, it converts to other bicyclic and tricyclic compounds in MeOH or CH3CN at room temperature.
authors.affiliation: Institute of Technology and Science, Graduate School of The University of Tokushima, Minami-josanjima-cho, Tokushima 770-8506, Japan. ueta@chem.tokushima-u.ac.jp kawamura@chem.tokushima-u.ac.jp.
authors.forename: Shoko
authors.initials: S
authors.lastname: Ueta
authors.forename: Kazuo
authors.initials: K
authors.lastname: Hida
authors.forename: Masaki
authors.initials: M
authors.lastname: Nishiuchi
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Kawamura