Bidentate Ruthenium Vinylcarbene Catalysts Derived from Enyne Metathesis

The preparation, structure, and catalytic activity of a series of bidentate η1-vinylcarbene ruthenium complexes derived from the standard metathesis catalysts 1, 2, or 4 by enyne metathesis with phenylacetylene derivatives bearing an isopropoxy substituent at their ortho position are described. Terminal as well as non-terminal phenylacetylene derivatives react with similar ease, thus providing ample opportunity for the preparation of catalysts with tailor-made properties. Use of the silyl propargyl ether derivative 13b as the substrate results in the formation of complex 15, in which the silyl ether moiety rather than the isopropoxy substituent ligates the metal center. The structures of the new chelate complexes 6, 7, 9, 14, and 15 in the solid state were determined by X-ray crystallography.