Synthesis of binuclear iridium(III) and rhodium(III) complexes bearing methylnaphthalene-linked N-heterocyclic carbenes, and application to intramolecular hydroamination

• Published in: Journal of organometallic chemistry Vol. 695; no. 12; pp. 1675 - 1681
• Main Authors: Ogata, Kenichi, Nagaya, Toshinori, Fukuzawa, Shin-ichi
• Format: Journal Article
• Language: English
• Published: LAUSANNE Elsevier B.V 01.06.2010; Elsevier
• Subjects: Binuclear complex; Chemistry; Chemistry, Inorganic & Nuclear; Chemistry, Organic; Intramolecular hydroamination; Iridium complex; N-heterocyclic carbene; Physical Sciences; Rhodium complex; Science & Technology; N-heterocyclic carbene; Intramolecular hydroamination; Iridium complex; Binuclear complex; Rhodium complex; ACTIVATION; ONE-POT SYNTHESIS; REACTIVITY; ALKYNES; INDOLES; OPPENAUER-TYPE OXIDATION; LIGANDS; ASYMMETRIC HYDROAMINATION; DIPHOSPHINE; CATALYZED CYCLIZATION
• ISSN: 0022-328X; 1872-8561
• DOI: 10.1016/j.jorganchem.2010.04.006

New methylnaphthalene-linked imidazolium salts 1 were synthesized through the reaction of 1,8-dibromomethylnaphthalene and N-alkylimidazole. On treatment of imidazolium salt 1 with silver oxide followed by [Cp∗MCl 2] 2 (M = Ir, Rh), binuclear iridium and rhodium complexes 2 were formed. Reaction of these complexes 2 with AgPF 6 afforded Cl-bridged cationic binuclear iridium and rhodium complexes 3. X-ray crystallographic analysis of 3 revealed that the two imidazole rings of the carbene ligand are in a parallel geometry. The cationic binuclear iridium complexes 3-Ir could be applied to the intramolecular hydroamination reaction of 2-ethynylaniline to give the corresponding indole compound. An binuclear iridium(III) and rhodium (III) complex bearing a methylnaphthalene-linked N-heterocyclic carbene was prepared by the reaction of [Cp∗MCl 2] 2 (M = Ir, Rh) with silver NHC complex. On treatment of the binuclear neutral complexes with AgPF 6, the Cl-bridged cationic iridium and rhodium complexes were formed. The cationic iridium complex could be applied to the intramolecular hydroamination of 2-ethynylaniline to give the corresponding indole compound. [Display omitted]