Preparation of triphenylphosphane substituted ethoxycarbonylcarbene-bridged dicobalt carbonyl complexes and their application as catalyst precursors in the carbonylation of ethyl diazoacetate to diethyl malonate

Triphenylphosphane substituted derivatives Co2(CO)6(CHCO2Et)(PPh3) (3) and Co2(CO)5(CHCO2Et)(PPh3)2 (4) were prepared from the known Co2(CO)7(CHCO2Et) and Co2(CO)6(CHCO2Et)2 complexes and were tested along with other phosphane-substituted cobalt carbonyl complexes as catalyst precursors in the carbonylation reaction of ethyl diazoacetate into diethyl malonate in the presence of ethanol.