Carbonyl insertion reactions of benzyl- and allyl-tricarbonyl-π-cyclopentadienylmolybdenum

Abstract

Treatment of a solution of benzyltricarbonyl-π-cyclopentadienylmolybdenum in acetonitrile with phosphines and phosphites (L) affords the crystalline complexes trans-PhCH₂·COMo(CO)₂(L)(π-C₅H₅); allyltricarbonyl-π-cyclopentadienylmolybdenum undergoes analogous reactions forming the complexes trans-C₃H₅·COMo(CO)₂(L)(π-C₅H₅). cls-But-2-enyltricarbonyl-π-cyclopentadienylmolybdenum reacts with triphenylphosphine in acetontrile to form trans-CH₃·CH[graphic omitted]CH·CH₂·COMo(CO)₂(Ph₃P)(π-C₅H₅). When trans-PhCH₂·COMo(CO)₂(Ph₃P)(π-C₅H₅) is heated (140°) decarbonylation occurs with the formation of PhCH₂Mo(CO)₂)Ph₃P)(π-C₅H₅). Kinetic measurements show that the rate-determining step in the carbonylation reactions does not involve the reacting ligand. The stereochemistry of these reactions is discussed on the basis of ¹H n.m.r. and i.r. spectroscopic measurements.