Palladium complexes of the type [Pd(L)Cl(PPh3)]Cl (L = 2-diphenylphosphinoamino)pyrimidine, or 2-diphenylphosphinoaniline), generated in situ by addition of one equivalent of PPh3 to the corresponding neutral complexes [Pd(L)Cl-2], were tested as catalysts for the methoxycarbonylation of styrene. The catalyst containing the pyrimidinyl ligand shows almost complete chemo- and regioselectivity together with a high conversion rate. However, in identical conditions, the [Pd(Ph2PNHC6H4PPh2)Cl-2] complex, where the P,N-ligand has been replaced by a related bidentate P-donor one, shows a significantly lesser performance. [GRAPHICS] .