Synthesis of N,P-, S,P-, P,P- and S,P,S-ligands using reactions of cyclopalladated complexes with KPPh2

• Palladacycles react with KPPh2 to give N,P-, S,P- and P,P-bidentate ligands.
• A Pd(II) SCS-Pincer complex reacts with KPPh2 to afford an S,P,S-tridentate ligand.
• Five- and six-membered palladacycles react with KPPh2 to form a C–P bond.
• The method provides aminophosphines and related bidentate ligands in 35–62% yield.

Readily available air- and moisture-stable dimeric chloro-bridged CN-, CS- and CP-cyclopalladated complexes with the (sp2)C–Pd bond react with 4.5 equiv. of KPPh2 in THF to give the corresponding P,N-, P,S- and P,P-bidentate ligands in 35–63% yield. The phosphination method is applicable to five- and six-membered palladacycles derived from (S)-N,N-dimethyl-1-phenylethylamine, (S)-4-tert-butyl-2-phenyl-2-oxazoline, benzyl methyl sulfide, benzyldiphenylphosphine, 2-benzylpyridine and N,N-dimethylbiphenyl-2-amine. The reaction of 1.2 equiv. of KPPh2 with the SCS-pincer cyclopalladated complex obtained from 1,3-bis(methylthiomethyl)benzene provided the corresponding S,P,S-tridentate ligand in 49% yield.

Dimeric chloro-bridged CN-, CS- and CP-cyclopalladated complexes with the (sp2)C–Pd bond react with 4.5 equiv. of KPPh2 in THF to give the corresponding N,P-, S,P- and P,P-bidentate ligands in 35–63% yield. The phosphination method is applicable to five- and six-membered Palladacycles.Figure optionsDownload as PowerPoint slide