title: Bulky aryloxide ligand stabilizes a heterogeneous metathesis catalyst.
abstract: The reaction of [W(=O)(=CHCMe2Ph)(dAdPO)2], containing bulky 2,6-diadamantyl aryloxide ligands, with partially dehydroxylated silica selectively yields a well-defined silica-supported alkylidene complex, [(≡SiO)W(=O)(=CHCMe2Ph)(dAdPO)]. This fully characterized material is a very active and stable alkene metathesis catalyst, thus allowing loadings as low as 50 ppm in the metathesis of internal alkenes. [(≡SiO)W(=O)(=CHCMe2Ph)(dAdPO)] also efficiently catalyzes the homocoupling of terminal alkenes, with turnover numbers exceeding 75,000 when ethylene is constantly removed to avoid the formation of the less reactive square-based pyramidal metallacycle resting state.
authors.affiliation: Department of Chemistry and Applied Biosciences, ETH-Zürich, Vladimir Prelog Weg 2, CH-8093, Zürich (Switzerland).
authors.forename: Matthew P
authors.initials: MP
authors.lastname: Conley
authors.forename: William P
authors.initials: WP
authors.lastname: Forrest
authors.forename: Victor
authors.initials: V
authors.lastname: Mougel
authors.forename: Christophe
authors.initials: C
authors.lastname: Copéret
authors.forename: Richard R
authors.initials: RR
authors.lastname: Schrock
keywords: NMR spectroscopy; alkenes; metallacycles; metathesis; tungsten