Fluorinated Biphenyl Phosphine Ligands for Accelerated [Au(I)]-Catalysis

Fluorinated JohnPhos-type ligands are proposed as accelerating tools in homogeneous gold(I) catalysis, with PedroPhosAuCl (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.