ja7b05216_si_002.cif (1.04 MB)

Stoichiometric and Catalytic Aryl–Perfluoroalkyl Coupling at Tri-tert-butylphosphine Palladium(II) Complexes

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posted on 11.08.2017, 00:00 by Devin M. Ferguson, James R. Bour, Allan J. Canty, Jeff W. Kampf, Melanie S. Sanford
This Communication describes studies of Ph–RF (RF = CF3 or CF2CF3) coupling at Pd complexes of general structure (PtBu3)­PdII(Ph)­(RF). The CF3 analogue participates in fast Ph-CF3 coupling (<5 min at 80 °C). However, the formation of side products limits the yield of this transformation as well as its translation to catalysis. DFT and experimental studies suggest that the side products derive from facile α-fluoride elimination at the 3-coordinate PdII complex. Furthermore, they show that this undesired pathway can be circumvented by changing from a CF3 to a CF2CF3 ligand. Ultimately, the insights gained from stoichiometric studies enabled the identification of Pd­(PtBu3)2 as a catalyst for the Pd-catalyzed cross-coupling of aryl bromides with TMSCF2CF3 to afford pentafluoroethylated arenes.