Annulation of Adiponitrile under the Action of Zirconocene Alkyne Complexes

The interaction of various precursors of alkyne complexes with adiponitrile upon heating is shown to lead to the formation of intermediate zirconaazacyclopentadiene zirconacycles. The intramolecular cyclization of the latter gives rise to tricyclic zirconaamidinate complexes containing a seven-membered tetrahydroazepimine moiety.