Heck, Suzuki and Kumada-Corriu cross-coupling reactions mediated by complexes based on the upper rim of diphosphinated calix[4]arenes

Two flexible bis-triarylphosphine chelators based on a calix[4]arene scaffold were assessed in combination with Pd or Ni as catalysts for CC bond forming reactions involving aryl halides. Both ligands resulted in efficient catalysts for Heck, Suzuki and Kumada-Corriu cross-coupling reactions. The diphosphines were shown to be superior to PPh3 when chlorobenzene was used as reagent.