Nitrogen-assisted ortho lithiation: One-pot synthesis of new classes of bidentate and tetradentate mixed P∼N ligands

Metalation of one aryl group of Ph₃P=NR (R = methyl, isopropyl) affords an easy access to the corresponding lithium salt, which in turn reacts with chlorophosphines R₂PCl (R = Ph, i-Pr) to yield a new class of bidentate ligand featuring one iminophosphorane and one phosphino group. Reaction of the phenyl derivative with [Pd(COD)Cl₂] yielded the expected six-membered palladacycle complex, which was structurally characterized. Extension of this new synthetic methodology toward the elaboration of enantiomerically pure tetradentate ligands has also been achieved.