Fluorinated Biphenyl Phosphine Ligands for Accelerated [Au(I)]-Catalysis
Riccardo Pedrazzani, Sofia Kiriakidi, Magda Monari, Irene Lazzarini, Giulio Bertuzzi, Carlos Silva López, Marco Bandini
Abstract
Fluorinated JohnPhos-type ligands are proposed as accelerating tools in homogeneous gold(I) catalysis, with PedroPhosAuC l ( Cat1 ) as the most efficient one. The ligands as well as the corresponding gold complexes were synthesized in high yields and fully characterized also via single-crystal X-ray diffraction. A secondary interaction between the distal phenyl ring of the phosphane ligand and the metal center is identified as key for the fine-tuning of the overall catalytic performance of the complexes. In particular, kinetic as well as computational analysis revealed that by accommodating F atoms on the biphenyl pendant of the ligand, more reactive organo-gold intermediates are realized toward subsequent nucleophilic condensations. The gold-catalyzed indole-hydroarylation of 1,6-enynes and the intramolecular hydroindolynation of alkynes have been adopted as benchmark reactions to exemplify these accelerating effects.