[52611-08-2] · C26H26Cl2P2Pd · Dichlorobis(methyldiphenylphosphine)palladium(II) · (MW 577.75)
Alternate Name: bis[(diphenylphosphino)methane]palladium(II) chloride.
Physical Data: 1H NMR (CDCl3) d 4.2 (t, CH3).
Preparative Methods: by treating commercially available K2PdCl2 (in DMF) with methyldiphenylphosphine (in CH2Cl2),1 or from K2PdCl2 (in H2O) and methyldiphenylphosphine (in CH2Cl2) using Bu4NCl (in CH2Cl2) as a phase-transfer catalyst.2
The title reagent (PdCl2(dppm)) is one of the most effective catalysts among transition-metal complexes for the preparation of a-keto amides and amides from aryl halides by treatment with secondary amines and carbon monoxide.3,4 These reactions are most commonly carried out without solvent at 100 °C at 10 atm of CO using a 1:3:0.1 molar ratio of aryl halide/secondary amine/PdCl2(dppm) (eq 1).
The reactivity of phenyl halides decreases in order of PhI > PhBr > PhCl,3 although the selectivity of biscarbonylation is higher with the bromo than with the iodo derivative.4 Introduction of electron-withdrawing substituents into the para position of phenyl halides enhances the reactivity but decreases the selectivity for a-keto amides.3 Amines with high basicity (pK
PdCl2(PBuPh2)2 has shown good results in the formation of a-keto amides from aryl halides upon treatment with secondary amines with Carbon Monoxide.3
Janak K. Padia
Parke-Davis Pharmaceutical Research, Ann Arbor, MI, USA