Angelino Doppiu

Simple synthetic routes to ruthenium–indenylidene olefin metathesis catalysts

An efficient synthetic protocol involving reactions between the free carbene and [RuCl(2)(PPh(3))(2)(Ind)] followed by addition of pyridine leads to the isolation of olefin metathesis active [RuCl(2)(L)(Py)(Ind)] (L = SIMes and SIPr) complexes. This novel approach circumvents the use of costly tricyclohexylphosphine.

Silica Immobilized Hoveyda Type Pre-Catalysts: Convenient and Reusable Heterogeneous Catalysts for Batch and Flow Olefin Metathesis

Two Hoveyda type ruthenium metathesis precatalysts, Umicore M51 and Umicore M71 SIMES, were immobilized on commercial silica in a simple and fast procedure through direct interaction with the support surface. These precatalysts exhibited good activity in ring-closing, cross, and enyne metathesis reactions and were stable in terms of reusability to be used for consecutive runs under both batch and flow conditions. In non-polar media, the catalytic activity of the precatalysts is truly based on a heterogeneous species, and the contamination of the products with ruthenium was very low with respect to starting catalyst (0.003–0.01 %; 0.13–0.44 ppm). If necessary, such as in solvents like toluene, the ruthenium content can easily be reduced to levels below 0.5 ppm by treatment of the crude metathesis products with the commercial scavenger QuadraSil AP or by use of an additional QuadraSil AP scavenger cartridge under flow conditions.

Synthesis Optimization and Catalytic Activity Screening of Industrially Relevant Ruthenium-Based Metathesis Catalysts

Olefin metathesis is a powerful catalytic reaction that has a huge potential in the pharmaceutical, polymer and specialty chemicals industries. Cost-effective industrial applications require large-scale availability of catalyst precursors which combine high activity, high selectivity and long life-time. Among the known numerous families of olefin metathesis catalysts, the Umicore M7-catalyst family represents a novel class of Hoveyda-type complexes showing excellent chemical stabilities and modular activity profiles. Relevant aspects related to their industrial synthesis as well as their catalytic performance in valuable olefin metathesis transformations are overviewed here.

(Sp)-1-Diphenyl­phosphanyl-2-{(S)-[2-(diphenyl­phosphan­yl)phen­yl]hydroxy­meth­yl}ferrocene

The absolute configuration of the title compound, [Fe(C5H5)(C36H29OP2)], is Sp at the ferrocene group and S at the asymmetric C atom. Both P atoms have a trigonal–pyramidal conformation. There is a short intramolecular C—H⋯P contact with an H⋯P distance of 2.56 Å. The hydroxy group is involved in an intramolecular O—H⋯πphenyl interaction. The crystal packing shows five very weak intermolecular C—H⋯π contacts, with H⋯Cg distances between 3.26 and 3.39 Å (Cg is the centroid of a phenyl or cyclopentadienyl ring).

Dichlorido(3-phenyl­indenyl­idene)bis­(triphenyl­phosphane)ruthenium(II) tetra­hydro­furan disolvate

The RuII atom in the title compound, [RuCl2(C15H10)(C18H15P)2]·2C4H8O, has a distorted square-pyramidal conformation. The P and Cl atoms are at the base of the pyramid and the Ru—Cindenylidene bond is in the axial position. The two Cl ligands and the two phosphane ligands are in trans positions. The Cl—Ru—Cl and P—Ru—P angles are 157.71 (2) and 166.83 (2)°, respectively. The two independent tetrahydrofuran (THF) solvent molecules are disordered. One THF molecule was refined using a split-atom model. The second THF molecule was accounted for by using program PLATON/SQUEEZE [Spek (2009 ▶). Acta Cryst. D65, 148–155]. The molecular conformation shows three intramolecular C—H⋯Cl contacts and two C—H⋯π interactions while the crystal packing features an intermolecular C—H⋯Cl contact and two very weak intermolecular C—H⋯π contacts.

(R p)-1-{(R)-(Dimethyl­amino)[2-(diphenyl­phosphan­yl)phen­yl]methyl}-2-(diphenyl­phosphan­yl)ferrocene chloro­form solvate

The absolute configuration of the title molecule, [Fe(C5H5)(C38H34NP2)]·CHCl3, is R,R p. The molecular structure is similar to the structure of the solvent-free compound [Fukuzawa, Yamamoto & Kikuchi (2007 ▶). J. Org. Chem. 72, 1514–1517], but some torsion angles about the P—Cphenyl bonds differ by up to 25°. The P atoms and the N atom have a distorted trigonal-pyramidal geometry. The chloroform solvate group donates a C—H⋯π bond to the central benzene ring and is also involved in six intermolecular C—H⋯Cl contacts with H⋯Cl distances between 2.96 and 3.13 Å.