trans-Chlorido[6-chloro-4-(4-methoxy­benz­yl)-3-oxo-3,4-dihydro­pyrazin-2-yl]­bis­(triphenyl­phosphine)palladium(II)

The title compound, [Pd(C12H10ClN2O2)Cl(C18H15P)2], is the inter­mediate of the reduction of a 3,5-dichloro­pyrazinone [Loosen, Tutonda, Khorasani, Compernolle & Hoornaert (1991 ▶). Tetra­hedron, 47, 9259–9268]. This species is formed by oxidative addition of coordinatively unsaturated Pd0 to the reactive 3-position of the heterocycle. The coordination around the Pd atom is square planar, with two trans PPh3 ligands. π–π inter­actions are observed between the centroid of the pyrazinone ring and planes of two adjacent phenyl rings, one from each PPh3 group (3.25 and 3.078 Å), stabilizing the inter­mediate structure. This could explain the reduced reactivity towards substitution of the Cl atom by the formate anion, resulting in poor yield of the reduced compound. 3-Substituted pyrazinones are important precursors in the synthesis of 5-amino­piperidinone-2-carboxyl­ate (APC) systems