title: Isolation, structure, and reactivity of an arylnickel(II) pivalate complex in catalytic C-H/C-O biaryl coupling.
abstract: We describe mechanistic studies of a C-H/C-O biaryl coupling of 1,3-azoles and aryl pivalates catalyzed by Ni(cod)2/dcype. This study not only supports a catalytic cycle consisting of C-O oxidative addition, C-H nickelation, and reductive elimination but also provides insight into the dramatic ligand effect in C-H/C-O coupling. We have achieved the first synthesis, isolation and structure elucidation of an arylnickel(II) pivalate, which is an intermediate in the catalytic cycle after oxidative addition of a C-O bond. Furthermore, kinetic studies and kinetic isotope effect investigations reveal that the C-H nickelation is the turnover-limiting step in the catalytic cycle.
authors.affiliation: Institute of Transformative Bio-Molecules (WPI-ITbM) and Graduate School of Science and §JST, ERATO, Itami Molecular Nanocarbon Project, Nagoya University , Nagoya 464-8602, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Muto
authors.forename: Junichiro
authors.initials: J
authors.lastname: Yamaguchi
authors.forename: Aiwen
authors.initials: A
authors.lastname: Lei
authors.forename: Kenichiro
authors.initials: K
authors.lastname: Itami
mesh_terms: D001393:Azoles / Q000737:chemistry*; D002384:Catalysis; D007700:Kinetics; D008958:Models, Molecular; D015394:Molecular Structure; D009532:Nickel / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D010421:Pentanoic Acids / Q000737:chemistry*
chemical_list: D001393:Azoles; D009942:Organometallic Compounds; D010421:Pentanoic Acids; D009532:Nickel; C005566:pivalic acid