LIGAND REDISTRIBUTION REACTIONS LEADING TO NEW PHOSPHINOENOLATE, METHYL PALLADIUM COMPLEXES - CRYSTAL-STRUCTURE OF [PD(ME)(PH(2)PCH-C(-O)PH)(PPH(3))]

Phosphinoenolate, methyl palladium(II) complexes were prepared in high yields by a sequence of reactions involving phosphine redistribution reactions. Thus, reaction of the dinuclear complex [Pd(Me)(mu-Cl){Ph(2 )PCH(2)C(O)NPh(2)}](2) 1 with PCy(3) in CH2Cl2 led to a mixture of [Pd (Me)Cl(PCy(3)){Ph(2)PCH(2)C(O)NPh(2)}] 2, trans-[Pd(Me)Cl(PCy(3))(2)] 3 and tran-[Pd(Me)Cl{Ph(2)PCH(2)C(O)NPh(2)}] 4. However, reaction of t his mixture with NaOMe in toluene afforded selectively [Pd(Me){Ph(2)PC H(...)C(O-...)Ph(2)}(PCy(3))] 5. This procedure was extended to the ke tophosphinoenolate complexes [Pd(Me){Ph(2)PCH(...)C(O-...)Ph}(PCy(3))] 7 and [Pd(Me){Ph(2)PCH(...)C(O-...)Ph}(PPh(3))] 8. Based on the ligan d redistributions observed, a high-yield one-pot synthesis of 5, 7 and 8 is described. The crystal structure of 8 was determined by X-ray di ffraction.