A combined ESI-MS/NMR mechanistic study on the palladium-catalysed cross-coupling reaction between aryldiazonium salts and aryltrifluoroborates with bis(mu-acetato)bis(4,4'difluoroazobenzene-C-2,N)dipalladium(II) (4) as the precatalyst is reported. The reaction follows a Pd-o/Pd-II cycle after reduction of 4 to a molecular Pd-o species (1), which according to the combined ESI-MS and F-19 NMR studies, bears an arylated azobenzene ligand. Oxidative addition by the diazonium salt generates the arylpalladium(II) intermediate (II), which was also detected in solution. The catalytic cycle completed with a transmetallation between 11 and the organoborate, which is followed by fast reductive elimination of the cross-coupling product to restore the molecular Pd-o species I. A concurrent activation path was also observed which consists of the formation of (4,4'-difluoroazobenzene C-2,N)dipalladium(II) tetrafluoroborate (7) by the reaction of 4 with the diazonium. salt and subsequent reduction by the aryltrifluoroborate to give I.

On the Mechanism of Palladium-Catalyzed Cross-Coupling of Diazonium Salts with Aryltrifluoroborates: A Combined ESI-MS/NMR Study / Taccardi, N.; Paolillo, R.; Gallo, Vito; Mastrorilli, Pietro; Nobile, C. F.; Räisänen, M.; Repo, T.. - In: EUROPEAN JOURNAL OF INORGANIC CHEMISTRY. - ISSN 1434-1948. - 29:(2007), pp. 4645-4652. [10.1002/ejic.200700532]

On the Mechanism of Palladium-Catalyzed Cross-Coupling of Diazonium Salts with Aryltrifluoroborates: A Combined ESI-MS/NMR Study

GALLO, Vito;MASTRORILLI, Pietro;
2007-01-01

Abstract

A combined ESI-MS/NMR mechanistic study on the palladium-catalysed cross-coupling reaction between aryldiazonium salts and aryltrifluoroborates with bis(mu-acetato)bis(4,4'difluoroazobenzene-C-2,N)dipalladium(II) (4) as the precatalyst is reported. The reaction follows a Pd-o/Pd-II cycle after reduction of 4 to a molecular Pd-o species (1), which according to the combined ESI-MS and F-19 NMR studies, bears an arylated azobenzene ligand. Oxidative addition by the diazonium salt generates the arylpalladium(II) intermediate (II), which was also detected in solution. The catalytic cycle completed with a transmetallation between 11 and the organoborate, which is followed by fast reductive elimination of the cross-coupling product to restore the molecular Pd-o species I. A concurrent activation path was also observed which consists of the formation of (4,4'-difluoroazobenzene C-2,N)dipalladium(II) tetrafluoroborate (7) by the reaction of 4 with the diazonium. salt and subsequent reduction by the aryltrifluoroborate to give I.
2007
On the Mechanism of Palladium-Catalyzed Cross-Coupling of Diazonium Salts with Aryltrifluoroborates: A Combined ESI-MS/NMR Study / Taccardi, N.; Paolillo, R.; Gallo, Vito; Mastrorilli, Pietro; Nobile, C. F.; Räisänen, M.; Repo, T.. - In: EUROPEAN JOURNAL OF INORGANIC CHEMISTRY. - ISSN 1434-1948. - 29:(2007), pp. 4645-4652. [10.1002/ejic.200700532]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11589/2307
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