Homogene Olefinmetathese mit Wolfram-Germanium- und Wolfram-Zinn-Komplexakatalysatoren/ Homogeneous Metathesis of Olefins by Tungsten-Germanium and Tungsten-Tin-Catalysts

Abstract

Bimetallic tungsten-germanium and tungsten-tin compounds (e.g. π-C5H5(CO)3W-MR3; M=Ge, Sn; R=CH3, C6H5) upon activation with Cl2Al-i-C4H9/O2 (2:1) give highly active catalytic systems for the homogeneous metathesis of linear olefins with internal double bonds (2-hexene, 3-heptene, 4-octene). The activation procedure has a decisive influence on the reaction velocity and the distribution of products. Starting the reaction by addition of oxygen to the mixture of the other compounds, the metathesis leads selectively and slowly to the primary metathesis products. On the other hand the metathesis takes place rapidly if the olefin is added to the preformed catalytic system. In this case metathesis is accompanied by strong double bond isomerisation and yields broad range olefin mixtures.