Reactivity of Ph₂PC≡CCMe₃ toward [PPhJfHFe₃CO)₁₁]: Synthesis and X-ray Structure of [PPh₄][Fe₃(CO)₆(μ-CO)(μ-PPh₂)(μ-C=CH(CMe₃))] and [PPh₄][Fe₂(CO)₆(μ-PPh₂CH==C(CMe₃)C(O))]•CH₂Cl₂

The reaction of Ph2PC=CCM3 with [PPh4]- [HFe3CO)11] in boiling ethyl acetate leads to the formation of [PPh4][Fe3(CO)6(μ-CO)2(μ-PPh2)(μ-C=CH(CMe3))] as the main product in which phosphorus-alkynyl bond cleavage has occurred and migration of hydrogen onto the β-carbon has led to a vinylidene ligand. The second product, [PPh4] [Fe2(CO)6(μ-Ph2PCH=C(CMe3)C(O))], contains a bridging ligand that results from hydrogen migration on the α-carbon of the alkynyl group and CO insertion between the β-carbon and one iron atom. © 1989, American Chemical Society. All rights reserved.