Rutheniumcluster‐vermittelter Aufbau von Kohlenstoff‐Ketten aus einem Phosphor‐Ylid und Alkinen

Ruthenium cluster‐Mediated Formation of Carbon Chains from a Phosphorus Ylide and Alkynes The phosphorus ylide Me3PCH — C(O)Ph induces fragmentation of Ru3(CO)12 with formation of the dinuclear complex Ru2(CO)7(μ21‐HC_… CPhCH — C(O)Ph) (1a) with a σ,π1‐bound allyl ligand, together with its PMe3 derivative 1b. The latter inserts PhCCPh into the Ru — C s̀ bond to yield two isomeric complexes Ru2(CO)5(PMe3)[μ1‐CPh \documentclass{article}\pagestyle{empty}\begin{document}$ \underline \cdots $\end{document} CPh \documentclass{article}\pagestyle{empty}\begin{document}$ \underline \cdots $\end{document} CH — CPhCH — C(O)Ph] (3a, b) with a (σ,π1‐allyl,π1‐olefin)1‐coordinated six‐carbon chain ligand. With HCCPh 1b undergoes double insertion with formation of the complex Ru2(CO)4(PMe3)(μ1‐CHCPhCH — CPhCH — CPhCH — C(O)Ph] (4) containing an eight‐carbon chain ligand with (σ,π1‐allyl,π1‐olefin,π1‐olefin) coordination. The structure of 3a (and thereby indirectly the constitution of 1 and 4) was proved by an X‐ray structure determination.