title: Template synthesis of benzannulated N-heterocyclic carbene ligands.
abstract: The reaction of 2-azidophenyl isocyanide (7) with [M(CO)(5)(thf)] (M=Cr, W) yields the isocyanide complexes [M(CO)(5)(7)] (M=Cr 8, M=W 9). Complexes 8 and 9 react with tertiary phosphines such as triphenylphosphane at the azido function of the isocyanide ligand to give the 2-triphenylphosphiniminophenyl isocyanide complexes 10 (M=Cr) and 11 (M=W). The polar triphenylphosphiniminophenyl function in complexes 10 and 11 can be hydrolyzed with H(2)O/HBr to afford triphenylphosphane oxide and the complexes containing the unstable 2-aminophenyl isocyanide ligand. This ligand spontaneously cyclizes by intramolecular nucleophilic attack of the primary amine at the isocyanide carbon atom to yield the 2,3-dihydro-1H-benzimidazol-2-ylidene complexes 12 (M=Cr) and 13 (M=W). Double deprotonation of the cyclic NH,NH-carbene ligands in 12 and 13 with KOtBu and reaction with two equivalents of allyl bromide yields the N,N'-dialkylated benzannulated N-heterocyclic carbene complexes 14 (M=Cr) and 15 (M=W). The molecular structures of complexes 9 and 11-15 were confirmed by X-ray diffraction studies.
authors.affiliation: Institut für Anorganische und Analytische Chemie Westfälische Wilhelms-Universität Münster Wilhelm-Klemm-Strasse 8, 48149 Münster, Germany. fehahn@uni-muenster.de
authors.forename: F Ekkehardt
authors.initials: FE
authors.lastname: Hahn
authors.forename: Volker
authors.initials: V
authors.lastname: Langenhahn
authors.forename: Nicole
authors.initials: N
authors.lastname: Meier
authors.forename: Thomas
authors.initials: T
authors.lastname: Lügger
authors.forename: Wolf Peter
authors.initials: WP
authors.lastname: Fehlhammer