摘要:
The reactions of the zerovalent palladium complex [Pd-2(dba)(3)] . CHCl3 (dba = dibenzylideneacetone, PhCH=CH-C(O)-CH=CHPh), in the presence of bidentate phosphorus ligand L-2 and dioxygen, with esters of 3-oxopentanedioic acid (RCH2COCH2R) in diethylether, afford, in good yield, the palladocyclobutan-3-one compounds [Pd(CHRCOCHR)L-2] [R = CO2Me, L-2 = dppe, dppp, dppb, dppf]. The compounds [Pd(CHRCOCHR)L-2] [R = CO2Me, L-2 dppe, dppp, dppb, dppf, R = CO2Et, L-2 = dppe] are also formed by treating dichloromethane solution of [Pd(COD)Cl-2] (COD cyclo-octa-1,5-diene) with RCH2COCH2R in the presence of silver(I) oxide and the appropriate bidentate ligand. Ligand exchange reactions of [Pd(eta(3)-CHRCOCHR)(L')(2)], (R = CO2Me, L' = PPh3 or AsPh3) complexes with appropriate chelating phosphorus donor ligand in dichloromethane have also afforded new complexes [Pd(CHRCOCHR)L-2] (L' = PPh3, L-2 = dppe, dppp; L' = AsPh3, L-2 = dppe, dppp, dppb, dppf). Spectroscopic data (IR, NMR, FAB MS) for the new compounds are reported. (C) 2002 Published by Elsevier Science Ltd.