Nucleophilic activation of triruthenium carbonyl complexes by semi-labile ancillary ligands. Cluster assisted codimerization of alkynes and ethylene to give 1,2-disubstituted-1,3-butadienes

Ruthenium/Halide Catalytic System for CC Bond Forming Reaction between Alkynes and Unsaturated Carbonyl Compounds

“…One more plausible pathway is to start from a ruthenium hydride as an active species, which adds first to 1a, as shown in Scheme 13. [23] Among these three possibilities, the last one (Scheme 13) may explain the formation of both geometrical isomers in the present catalytic reaction. Thus, the insertion of an alkyne to a ruthenium-hydride bond gives a vinyl ruthenium species, followed by carboruthenation to ethyl acrylate, and then b-hydrogen elimination gives the isomeric products.…”

Reactivity of Alkynes Containing α‐Hydrogen Atoms with a Triruthenium Hydrido Carbonyl Cluster: Alkenyl versus Allyl Cluster Derivatives

“…It has been established that the face-capped alkenyl derivatives are not precursors to the allyl products, which are formed via edge-bridged alkenyl intermediates. At higher temperature 6 ] (12) are also formed in these reactions). A DFT theoretical study has allowed a comparison of the thermodynamic stabilities of isomeric compounds and has helped rationalize the experimental results.…”

“…However, to date, the number of reports dealing with triruthenium-carbonyl cluster complexes containing alkenyl ligands is relatively small, [1][2][3][4][5] despite the fact that some of these clusters have been recognized as intermediates or as catalyst precursors for alkyne-alkene co-dimerization [6] and alkyne hydrogenation, [7] dimerization, [2b] polymerization, [2b] and hydroformylation [2c] processes. Without exception, these alkenyl-triruthenium cluster complexes arise from reactions of alkynes with triruthenium precursors containing hydride ligands.…”

“…In this context, we have recently reported the reactivity of the hydrazido-bridged hydrido-carbonyl-triruthenium complex [Ru 3 (m-H)(m 3 -k 2 -HNNMe 2 )(CO) 9 ] [8] (1) with a variety of terminal and internal alkynes without a-hydrogen atoms, showing that the products may have their alkenyl ligands in edge-bridging or face-capping positions (Scheme 1) and that 2 -(CO) 6 ] (11) from 3-methoxy-1-propyne. The regioselectivity of these reactions depends upon the nature of the alkyne reagent, which affects considerably the kinetic barriers of important reaction steps and the stability of the final products.…”

Structural characterization of 1,1,1,2,2,2,3,3,3-nonacarbonyl-1,2-μ-iodo-1,2,3-[μ3-(phenylpyridylphosphido)-μ-P,N]-triangulo-triruthenium

“…As part of our efforts to tailor ruthenium carbonyl clusters for applications in homogeneous catalysis (Lugan, Laurent, Lavigne, Newcomb, Liimatta & Bonnet, 1990), we have devised a series of complexes that combine two different kinds of ancillary ligands, namely (i) a face-bridging polydentate group which contributes to the retention of the metal ensemble under catalytic conditions, and (ii) a lightly bridging ligand which is susceptible to the opening of a vacant coordination site on the cluster by simply moving to a terminal position. In the title complex, the above ligand types are respectively represented by a phosphidopyridyl group (Lugan, Lavigne, Bonnet, Rrau, Niebecker & Tkatchenko, 1988) and an iodide atom (Han, Geoffroy & Rheingold, 1987;Lavigne, 1990). The formation of this neutral complex is the result of an electrophilic addition of I ÷ to the metal--metal bond of an electron-rich polymetallic precursor.…”