Chelating carbene ligand precursors and their use in the synthesis of metathesis catalysts

A method of preparing ruthenium or osmium complexes with chelating carbene ligands comprising contacting a ruthenium or osmium carbene complex of the formula X1X2L1L2M═CR1R2 with an internal olefin ligand precursor of the formula:

• wherein
• X1 and X2 are each, independently, any anionic ligand;
• L1 and L2 are each, independently, any neutral electron donor,
• M is ruthenium or osmium;
• R1 and R2 are each, independently, selected from hydrogen or a substitutent selected from the group consisting of alkyl, alkenyl, alkynyl, aryl, alkylcarboxylate, arylcarboxylate, alkoxy, alkenyloxy, alkynyloxy, aryloxy, alkoxycarbonyl, alkylthio, alkylsulfonyl, alkylsulfinyl, and trialkylsilyl, wherein each of the substituents is substituted or unsubstituted;
• R3 and R4 are each, independently, selected from hydrogen or a substitutent selected from the group consisting of alkyl, aryl, alkoxy, aryloxy, C2-C20 alkoxycarbonyl, and C1-C20 trialkylsilyl, wherein each of the substituents is substituted or unsubstituted;
• R5, R6, R7, and R8 are each, independently, selected from the group consisting of hydrogen, halogen, alkyl, alkenyl, alkynyl, aryl, heteroaryl, alkoxy, alkenyloxy, aryloxy, alkoxycarbonyl, carbonyl, alkylamino, alkylthio, alkylsulfonyl, nitrile, nitro, alkylsulfinyl, trihaloalkyl, perfluoroalkyl, carboxylic acid, ketone, aldehyde, nitrate, cyano, isocyanate, hydroxyl, ester, ether, amine, imine, amide, sulfide, disulfide, sulfonate, carbamate, silane, siloxane, phosphine, phosphate, or borate;
• Y is a heteroatom selected from the group oxygen (O), sulfur (S), nitrogen (N), or phosphorus (P);
• n is 1, in the case of a divalent heteroatom such as O or S, or 2, in the case of a trivalent heteroatom such as N or P;
• and
• Z is a group selected from hydrogen, alkyl, aryl, functionalized alkyl, functionalized aryl where the functional group(s) may independantly be one or more or the following:
• alkoxy, aryloxy, halogen, carboxylic acid, ketone, aldehyde, nitrate, cyano, isocyanate, hydroxyl, ester, ether, amine, imine, amide, sulfide, disulfide, carbamate, silane, siloxane, phosphine, phosphate, or borate.