A novel synthesis of atropisomeric P,N ligands by catalytic phosphination using triarylphosphines

The novel palladium-catalyzed phosphination using triarylphosphines as the phosphinating agents was developed and applied to the synthesis of atropisomeric P,N ligands from their corresponding O,N triflates. Various P,N ligands that possessed different dihedral angles and electronic properties were prepared from corresponding O,N triflates and triarylphosphines, respectively. The Pd-Ar/P-Ar''exchange reactions were found to occur in this phosphination as the key step. The brief mechanistic studies concerning the rate of reactions and the coordination mode of O,N triflates to the palladium center are discussed.