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

Abstract

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.