Preparation of ruthenium alkylidene complexes as catalysts for cross-metathesis reactions of functionalized and substituted olefins.
The invention pertains to the use of Group 8 transition metal carbene complexes as catalysts for olefin cross-metathesis reactions. In particular, ruthenium and osmium alkylidene complexes substituted with an N-heterocyclic carbene ligand are used to catalyze cross-metathesis reactions to provide a variety of substituted and functionalized olefins, including phosphonate-substituted olefins, directly halogenated olefins, 1,1,2-trisubstituted olefins, and quaternary allylic olefins. The invention further provides a method for creating functional diversity using the aforementioned complexes to catalyze cross-metathesis reactions of a first olefinic reactant, which mayor may not be substituted with a functional group, with each of a plurality of different olefinic reactants, which may or may not be substituted with functional groups, to give a plurality of structurally distinct olefinic products. The methodol. of the invention is also useful in facilitating the stereoselective synthesis of 1,2-disubstituted olefins in the cis configuration. In a typical example of the synthesis of substituted allylic olefins, allyldiphenylphosphine oxide and RuCl2(:CHPh)(IMesH2)(PCy3) (synthetic prepn. given) [IMesH = (I)] are added to cis-2-butene-1,4-diacetate to give 90% of the cross product. [on SciFinder(R)]