Friday, November 30, 2012

Rate and Mechanism of the Oxidative Addition of Vinyl Triflates and Halides to Palladium(0) Complexes in DMF


In a coordinating solvent such as DMF, the fast oxidative addition of vinyl triflates to Pd0(PPh3)4 performed under stoichiometric conditions gives the cationic complexes [(η1-vinyl)Pd(PPh3)2(DMF)]+TfO-, which have been characterized by conductivity measurements, electrospray mass spectrometry, and NMR spectroscopy, before their decomposition to vinylphosphonium salts [vinyl-PPh3]+TfO- and Pd0 complexes. [(η1-vinyl)Pd(PPh3)2(DMF)]+TfO- complexes are less stable than [(aryl)Pd(PPh3)2(DMF)]+TfO- formed in the oxidative addition of aryl triflates to Pd0(PPh3)4. The rate constant of the oxidative addition of vinyl triflates and bromides to Pd0(PPh3)4 has been determined and compared to that of aryl triflates and halides. The following reactivity orders are established in DMF: vinyl-OTf vinyl-Br > PhBr and vinyl-OTf PhOTf.

Rate and Mechanism of the Oxidative Addition of Vinyl Triflates and Halides to Palladium(0) Complexes in DMF. Anny Jutand* and and Serge Négri. Organometallics 2003 22 (21), 4229-4237

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