title: Oxidative Addition of Haloheteroarenes to Palladium(0): Concerted versus SN Ar-Type Mechanism.
abstract: The kinetics of the oxidative additions of haloheteroarenes HetX (X=I, Br, Cl) to [Pd(0) (PPh3 )2 ] (generated from [Pd(0) (PPh3 )4 ]) have been investigated in THF and DMF and the rate constants have been determined. In contrast to the generally accepted concerted mechanism, Hammett plots obtained for substituted 2-halopyridines and solvent effects reveal a reaction mechanism dependent on the halide X of HetX: an unprecedented SN Ar-type mechanism for X=Br or Cl and a classical concerted mechanism for X=I. These results are supported by DFT studies.
authors: Organic Synthesis, Department of Chemistry, University of Antwerp, 2020 Antwerpen (Belgium). bert.maes@uantwerpen.be.
authors: Bert U W
authors: BU
authors: Maes
authors: Stefan
authors: S
authors: Verbeeck
authors: Tom
authors: T
authors: Verhelst
authors: Audrey
authors: A
authors: Ekomié
authors: Niklas
authors: N
authors: von Wolff
authors: Guillaume
authors: G
authors: Lefèvre
authors: Emily A
authors: EA
authors: Mitchell
authors: Anny
authors: A
authors: Jutand
keywords: arenes; homogeneous catalysis; kinetics; oxidative addition; reaction mechanisms