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  • Molybdenum and tungsten imido alkylidene complexes as efficient olefin-metathesis catalysts.

Molybdenum and tungsten imido alkylidene complexes as efficient olefin-metathesis catalysts.

Angewandte Chemie (International ed. in English) (2003-10-09)
Richard R Schrock, Amir H Hoveyda
ABSTRACT

Catalytic olefin metathesis has quickly emerged as one of the most often-used transformations in modern chemical synthesis. One class of catalysts that has led the way to this significant development are the high-oxidation-state alkylidene complexes of molybdenum. In this review key observations that resulted in the discovery and development of molybdenum- and tungsten-based metathesis catalysts are outlined. An account of the utility of molybdenum catalysts in the synthesis of biologically significant molecules is provided as well. Another focus of the review is the use of chiral molybdenum complexes for enantioselective synthesis. These highly efficient catalysts provide unique access to materials of exceptional enantiomeric purity and often without generating solvent waste.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Tungsten, powder, 12 μm, 99.9% trace metals basis
Sigma-Aldrich
Tungsten, foil, thickness 0.25 mm, ≥99.9% trace metals basis
Sigma-Aldrich
Tungsten, powder (monocrystalline), 0.6-1 μm, ≥99.9% trace metals basis
Tungsten, insulated wire, 5m, conductor diameter 0.075mm, insulation thickness 0.02mm, PTFE (polytetrafluoroethylene) insulation, 99.9%
Tungsten, insulated wire, 10m, conductor diameter 0.05mm, insulation thickness 0.008mm, polyimide insulation, 99.9%
Tungsten, microfoil, disks, 10mm, thinness 0.25μm, specific density 474μg/cm2, permanent mylar 3.5μm support, 99.95%
Tungsten, insulated wire, 0.2m, conductor diameter 0.015mm, insulation thickness 0.002mm, polyimide insulation, 99.9%
Tungsten, foil, 5m coil, thickness 0.025mm, coil width 1mm, as rolled, 99.95%
Tungsten, insulated wire, 20m, conductor diameter 0.05mm, insulation thickness 0.008mm, polyimide insulation, 99.9%
Tungsten, foil, not light tested, 50x50mm, thickness 0.004mm, 99.95%
Tungsten, foil, light tested, 150x150mm, thickness 0.05mm, as rolled, 99.95%
Tungsten, lump, 200g, max. size 5mm
Tungsten, insulated wire, 2m, conductor diameter 0.075mm, insulation thickness 0.02mm, PTFE (polytetrafluoroethylene) insulation, 99.9%
Tungsten, rod, 200mm, diameter 6.35mm, centerless ground, 99.95%
Tungsten, foil, light tested, 50x50mm, thickness 0.075mm, as rolled, 99.95%
Tungsten, foil, not light tested, 25x25mm, thickness 0.004mm, 99.95%
Tungsten, insulated wire, 2m, conductor diameter 0.025mm, insulation thickness 0.005mm, polyimide insulation, 99.9%
Tungsten, foil, 30mm disks, thickness 1.0mm, as rolled, 99.95%
Tungsten, foil, light tested, 150x150mm, thickness 0.075mm, as rolled, 99.95%
Tungsten, lump, 50g, max. size 5mm
Tungsten, insulated wire, 1m, conductor diameter 0.015mm, insulation thickness 0.002mm, polyimide insulation, 99.9%
Tungsten, microfoil, disks, 10mm, thinness 0.05μm, specific density 96μg/cm2, permanent mylar 3.5μm support, 99.95%
Tungsten, insulated wire, 2m, conductor diameter 0.0125mm, insulation thickness 0.0035mm, polyimide insulation, 99.9%
Tungsten, foil, light tested, 150x150mm, thickness 0.025mm, as rolled, 99.95%
Tungsten, microfoil, disks, 10mm, thinness 0.1μm, specific density 182μg/cm2, permanent mylar 3.5μm support, 99.95%
Tungsten, wire reel, 0.5m, diameter 1.0mm, clean, 99.95%
Tungsten, insulated wire, 2m, conductor diameter 0.015mm, insulation thickness 0.002mm, polyimide insulation, 99.9%
Tungsten, foil, not light tested, 50x50mm, thickness 0.007mm, 99.95%
Tungsten, foil, not light tested, 25x25mm, thickness 0.006mm, 99.95%
Tungsten, mesh, 100x100mm, nominal aperture 0.2mm, wire diameter 0.05mm, 100 wires/inch, open area 64%, plain weave mesh, 99.95%