Synthesis of ruthenium or osmium metathesis catalysts

[0007] The present invention is a divisional of U.S. application Ser. No. 09/672,585 filed Sep. 28, 2000, now U.S. Pat. No. 6,313,332, which is a divisional of issued U.S. application Ser. No. 09/523,017 filed Mar. 10, 2000, now U.S. Pat. No. 6,153,778, which is a divisional of issued U.S. application Ser. No. 09/253,042 filed Feb. 19, 1999, now U.S. Pat. No. 6,048,993, which is a divisional of issued U.S. application Ser. No. 08/966,011 filed Nov. 7, 1997, now U.S. Pat. No. 5,917,071, all of which are entitled SYNTHESIS OF RUTHENIUM OR OSMIUM METATHESIS CATALYSTS by inventors Robert H. Grubbs, Tomas R. Belderrain, Seth N. Brown, Thomas E. Wilhelm, the contents of each of which are incorporated herein by reference.

[0008] This application claims the benefit of U.S. Provisional Application No. 60/031,088, filed Nov. 15, 1996 by inventors Robert H. Grubbs, Tomas Belderrain, and Seth N. Brown entitled “Synthesis of Ruthenium Metathesis Catalysts from Ruthenium Hydride Complexes” which is incorporated herein by reference.

[0010] The present invention relates to the synthesis of highly active ruthenium or osmium carbene metathesis catalysts. To the synthetic organic or polymer chemist, simple methods for forming carbon-carbon bonds are extremely important and valuable tools. One method of C—C bond formation that has proved particularly useful is transition-metal catalyzed olefin metathesis. The past two decades of intensive research effort has recently culminated in the discovery of well defined ruthenium and osmium carbene complex catalysts that are highly metathesis active and stable in the presence of a variety of functional groups.

[0011] These ruthenium and osmium carbene complexes have been described in U.S. Pat. Nos. 5,312,940 and 5,342,909 and U.S. patent applications Ser. Nos. 08/708,057, 08/282,827 and 08/693,789, all of which are incorporated herein by reference. The ruthenium and osmium carbene complexes disclosed in these patents and applications all possess metal centers that are formally in the +2 oxidation state, have an electron count of 16, and are penta-coordinated. These catalysts are of the general formula

[0012] where M is ruthenium or osmium, X and X¹are anionic ligands, and L and L¹are neutral electron donors and R and R′ are specific substituents that will be described in more detail below.

[0013] U.S. Pat. Nos. 5,312,940 and 5,342,909 disclose specific vinyl alkylidene ruthenium and osmium complexes in which the neutral electron donor ligands L and L¹are triphenyl phosphines or diphenylmethyl phosphines. As disclosed in the patents, the catalysts are useful in catalyzing the ring opening metathesis polymerization (“ROMP”) of strained olefins. U.S. patent applications Ser. Nos. 08/708,057 and 08/282,827 disclose specific vinyl alkylidene ruthenium and osmium complexes in which the neutral electron donor ligands L and L¹are phosphines with at least one secondary-alkyl or cycloalkyl substituent. These secondary-alkyl phosphine catalysts are more metathesis active than the corresponding triphenyl phosphine catalysts and may be used to catalyze a variety of metathesis reactions involving acyclic and unstrained cyclic olefins. U.S. patent application Ser. No. 08/693,789 discloses specific non-vinyl alkylidene complexes that are more metathesis active than their vinyl alkylidene counterparts. The preferred catalyst disclosed in this application are benzylidene ruthenium and osmium carbene compounds.

[0014] As disclosed by U.S. Pat. Nos. 5,312,940 and 5,342,909, vinyl alkylidene catalysts may be synthesized by a variety of methods including the reaction of ruthenium or osmium compounds with cyclopropenes or phosphoranes, and neutral or anionic ligand exchange. Of these previous methods, the preferred method of making the catalysts is via the reaction of a substituted cyclopropene with a ruthenium or osmium dihalide. Unfortunately, this method is limited to the synthesis of vinyl alkylidene catalysts (i.e., catalysts in which R is hydrogen and R¹is a substituted vinyl group) and cannot be used to directly synthesize the secondary-alkyl phosphine catalysts disclosed in the Ser. Nos. 08/282,826 and 08/282,827 applications. The synthesis of these secondary-alkyl phosphine catalysts further requires reacting the triphenyl phosphine catalysts produced from the cyclopropene reaction with secondary-alkyl phosphines in a ligand exchange reaction.

[0015] In part to overcome the fact that the cyclopropenes are not readily available and are generally limited to the synthesis of vinyl alkylidene catalysts, U.S. patent application Ser. No. 08/693,789 discloses a method for synthesizing alkylidene complex catalysts via the reaction of substituted diazoalkanes with ruthenium dihalides. The synthetic procedures disclosed in this application can be used to make non-vinyl alkylidene complex catalysts which are more metathesis active than their corresponding vinyl alkylidene counterparts. As in the cyclopropene based methods, the secondary-alkyl phosphine catalysts cannot be synthesized directly from the reaction of ruthenium dihalide and diazoalkanes. Instead, the secondary-alkyl phosphine catalysts must be synthesized by ligand exchange. Although the use of diazo starting materials greatly broadened the range of ruthenium and osmium carbene catalysts that could be synthesized, the danger of handling diazocompounds on a large scale severely restricts the commercial and laboratory utility of this method. In addition, the diazo method requires the synthesis to be conducted at low temperature (about −80° C. to −50° C.) and requires the use of considerable solvent in the final purification of the catalyst. As with the cyclopropene synthesis method, the secondary-alkyl phosphine catalysts must be synthesized using a multi-step ligand exchange procedure which may be time consuming and expensive and may result in lower product yields.

[0016] In both the cyclopropene and diazo synthesis methods the secondary-alkyl phosphine catalysts must be synthesized using a multi-step, ligand exchange procedure. Since the secondary-alkyl phosphine catalysts are more metathesis active than the triphenyl phosphine catalysts and therefore may have wider commercial utility, the necessity of a multi-step synthesis in these cases can be a severe limitation.

[0017] Although the previous methods have been adequate to make reasonable quantities of the ruthenium and osmium carbene catalysts, as the number of scientific and commercial applications of these catalysts continues to increase, a need exists for simple, safe, and inexpensive methods of synthesizing these compounds to fully exploit their potential.

[0018] The present invention addresses this need and provides simple, safe, and less expensive methods of synthesizing ruthenium and osmium carbene catalysts. In general, one step syntheses are provided using stable, readily available starting materials. The processes result in good product yield without the need for expensive and sophisticated equipment. In addition, both vinyl and non-vinyl alkylidene catalysts may be synthesized. Moreover, the methods can produce catalysts in a form which makes post synthesis purification unnecessary.

[0019] In one aspect of the present invention, a method for synthesizing ruthenium and osmium carbene complex catalysts of the formula

[0020] is provided where M is ruthenium or osmium; X and X¹are any anionic ligand, preferably chloride; and L and L¹are any neutral electron donor ligand, preferably tricycloalkylphosphines; and, R¹may be any one of a variety of substituents which are described in detail below. In the preferred catalyst, R¹is phenyl. In this embodiment of the invention, a compound of the formula

[0021] (n=1 or 2) is contacted with a compound of the formula R¹C(X) (X¹)H in the presence of an olef in to yield the required ruthenium or osmium carbene complex catalyst.

[0022] In another aspect of the present invention, a method for synthesizing vinyl alkylidene catalysts of the formula

[0023] is provided where M, X, X¹, L, and L¹are as described above and R¹², R¹³, and R¹⁷may be the same or different and may be any one of a variety of substituents that are described in detail below. In the preferred catalyst, R¹²and R¹³are the same and are both methyls and R¹⁷is hydrogen. In this embodiment of the invention, a compound of the formula

[0024] (n=1 or 2) is contacted with a compound of the formula

[0025] to yield the required ruthenium or osmium carbene complex catalyst.

[0026] Alternatively, the alkyne may be of the general formula, R¹⁷C≡CCR¹²R¹³R′, wherein R′ is hydroxyl. In this variation, the alkyne is reacted with the dihydrogen complex as above but then subsequently reacted with HX to form the above described vinyl alkylidene catalyst. However, in another variation of this reaction scheme, when R′ is hydrogen or a C₁-C₂₀alkyl, the method produces a non-vinyl alkylidene catalyst of the general formula, (X)(X¹)(L)(L¹)M═C(R¹⁷)(CH₂CR¹²R¹³R′).

[0027] In yet another aspect of the present invention, a method for synthesizing compounds of the formula

[0028] is provided where M, X, X¹, L, and L¹are as described above and R¹⁴, R¹⁵, and R¹⁶may be any one of a variety of substituents that are described in detail below. In this embodiment of the invention, a compound of the formula

[0029] (n=1 or 2) is contacted with a compound of the formula

[0030] to yield the required ruthenium or osmium carbene complex catalyst.

[0031] General Description of the Catalysts

[0032] The methods of the present invention may be used to synthesize ruthenium or osmium carbene complex catalysts that include a ruthenium or osmium metal center that is in a +2 oxidation state, have an electron count of 16, and are penta-coordinated. More specifically, the methods of the present invention may be used to synthesize compounds with the formula

[0033] wherein

[0034] M is ruthenium or osmium;

[0035] X and X¹are independently any anionic ligand;

[0036] L and L¹are any neutral electron donor ligand;

[0037] R and R¹are each hydrogen or one of the following substituent groups: C₁-C₂₀, alkyl, C₂-C₂₀alkenyl, C₂-C₂₀alkynyl, aryl, C₁-C₂₀carboxylate, C₁-C₂₀alkoxy, C₂-C₂₀alkenyloxy, C₂-C₂₀alkynyloxy, aryloxy, C₂-C₂₀alkoxycarbonyl, C₁-C₂₀alkylthic, C₁-C₂₀alkylsulfonyl and C₁-C₂₀alkylsulfinyl. Optionally, the substituent group may be substituted with one or more groups selected from C₁-C₅alkyl, C₁-C₅alkoxy, and aryl. When the substitute aryl group is phenyl, it may be further substituted with one or more groups selected from a halogen, a C₁-C₅alkyl, or a C₁-C₅alkoxy. Moreover, the R¹substituent may further include one or more functional groups. Examples of suitable functional groups include but are not limited to: hydroxyl, thiol, thioether, ketone, aldehyde, ester, ether, amine, imine, amide, nitro, carboxylic acid, disulfide, carbonate, isocyanate, carbodiimide, carboalkoxy, carbamate, and halogen.

[0038] In a preferred embodiment, the R substitutent is hydrogen and the R¹substituent is one of the following: (1) hydrogen; (2) C₁-C₂₀alkyl; (3) C₂-C₂₀alkenyl (4) aryl; (5) C₁-C₂₀alkyl substituted with one or more groups selected from the group consisting of aryl, halogen, hydroxy, C₁-C₂₀alkoxy, and C₂-C₅alkoxycarbonyl; and (6) aryl substituted with one or more groups selected from the group consisting of C₁-C₅alkyl, aryl, hydroxyl, C₁-C₅alkoxy, amino, nitro, and halogen. In a more preferred embodiment, the R¹substituent is phenyl or phenyl substituted with a group selected from the group consisting of chloride, bromide, iodide, fluoride, —NO₂, —NMe₂, methoxy, and methyl. In the most preferred embodiment, the R¹substituent is phenyl.

[0039] The L and L¹ligands may be the same or different and may be any neutral electron donor ligand. In a preferred embodiment, the L and L¹ligands may be the same or different and may be phosphines, sulfonated phosphines, phosphites, phosphinites, phosphonites, arsines, stibines, ethers, amines, amides, imines, sulfoxides, carboxyls, nitrosyls, pyridines, and thioethers. In a more preferred embodiment, the L and L¹ligands may be the same or different and are phosphines of the formula PR³R⁴R⁵, where R³is a secondary alkyl or cycloalkyl group, and R⁴and R⁵are the same or different and may be aryl, C₁-C₁₀primary alkyl, secondary alkyl, or cycloalkyl groups. In the most preferred embodiment, the L and L¹ligands may be the same or different and are —P(cyclohexyl)₃, —P(cyclopentyl)₃, or —P(isopropyl)₃.

[0040] The X and X¹ligands may be the same or different and may be any anionic ligand. In a preferred embodiment, the X and X¹ligands may be the same or different and may be a halogen, hydrogen or one of the following groups: C₁-C₂₀alkyl, aryl, C₁-C₂₀alkoxide, aryloxide, C₃-C₂₀alkyldiketonate, aryldiketonate, C₁-C₂₀carboxylate, aryl or C₁-C₂₀alkylsulfonate, C₁-C₂₀alkylthio, C₁-C₂₀alkylsulfonyl, or C₁-C₂₀alkylsulfinyl. Each group may optionally be substituted with C₁-C₅alkyl, halogen, C₁-C₅alkoxy or with a phenyl group. The phenyl group in turn may optionally be substituted with halogen, C₁-C₅alkyl or C₁-C₅alkoxy. In a more preferred embodiment, the X and X¹ligands may be the same or different and may be chloride, bromide, iodide, hydrogen or a moiety selected from a group consisting of: benzoate, C₁-C₅carboxylate, C₁-C₅alkyl, phenoxy, C₁-C₅alkoxy, C₁-C₅alkylthio, aryl, and C₁-C₅alkyl sulfonate. Each moiety may optionally be substituted with C₁-C₅alkyl or a phenyl group. The phenyl group may optionally be substituted with halogen, C₁-C₅alkyl or C₁-C₅alkoxy. In an even more preferred embodiment, the X and X¹ligands may be the same or different and may be chloride, CF₃CO₂, CH₃CO₂, CFH₂CO₂, (CH₃)₃CO, (CF₃)₂(CH₃)CO, (CF₃) (CH₃)₂CO, PhO, MeO, EtO, tosylate, mesylate, or trifluoromethanesulfonate. In the most preferred embodiment, X and X¹are both chloride.

[0041] The most preferred catalysts are

[0042] where Cy is cyclohexyl or cyclopentyl and Me is methyl.

[0043] The above catalysts are stable in the presence of a variety of functional groups including hydroxyl, thiol, ketone, aldehyde, ester, ether, amine, imine, amide, nitro, carboxylic acid, disulfide, carbonate, isocyanate, carbodiimide, carboalkoxy, and halogen. Therefore, the starting materials and products of the reactions described below may contain one or more of these functional groups without poisoning the catalyst. In addition, the catalysts are stable in the presence of aqueous, organic, or protic solvents, for example, aromatic hydrocarbons, chlorinated hydrocarbons, ethers, aliphatic hydrocarbons, alcohols, water, or mixtures of the above. Therefore, the reactions described below may be carried out in one or more of these solvents without poisoning the catalyst product.

[0044] General Synthetic Schemes

[0045] The present invention relates to new routes for synthesizing the above-described ruthenium and osmium carbene catalysts which eliminate many of the problems associated with previous methods. Unless explicitly stated otherwise, the substituents of the catalyst are as defined above.

[0046] We have discovered that the ruthenium and osmium carbene catalysts may be synthesized in one-step syntheses using readily available and stable carbene and metal sources. As will be described in detail below, the methods of the present invention allow for the synthesis of ruthenium and osmium carbene complex compounds without the use of unstable starting materials and using reactions that may be run at room temperature or above. The method also allows for the preparation of catalysts with varying anionic and neutral electron donor ligands and varying substituents on the carbene carbon. The methods of the present invention generally yield the carbene complexes in greater than 90% yield and are sufficiently clean that the resulting catalysts may be used without extensive post synthesis purification. As discussed in the background section, all of these aspects of the present invention possess important advantages over the existing methods.

[0047] We have discovered three routes through which the catalysts may be synthesized involving a ruthenium or osmium dihydrogen complex and a simple organic compound. The two general forms of the dihydrogen complex are M(H)₂(H₂)_nL¹L and M(H)X(H₂)_nL¹L wherein M, X, L and L¹are as previously defined and n is 1 or 2. Because the dissociation of the first dihydrogen species is facile, the single dihydrogen (n=1) and bis(dihydrogen) (n=2) complexes are essentially interchangeable. In general, the bis(dihydrogen) complex predominates in the solid form of the complex and the single(dihydrogen) complex predominates in solution.

[0048] In the first route, the dihydrogen complex is M(H)₂(H₂)_nL¹L and the organic compound is a substituted alkane which includes a carbon atom bearing the X, X¹, and R¹substituents of the catalyst. In the second route, the dihydrogen complex is M(H)(X)(H₂)_nL¹L and the organic compound is a substituted alkyne. In the third route, the dihydrogen complex is M(H)(X)(H₂)_nL¹L and the organic compound is an alkene (olefin).

[0049] For clarity and ease of presentation, specific reaction conditions and procedures are collected together in the final Experimental Procedures section.

[0050] This embodiment of the invention may be summarized in Reaction Scheme 1, below.

[0051] This embodiment includes a process for synthesizing a compound of the formula

[0052] which comprises the step of contacting a compound of the formula

[0053] with a compound of the formula R¹C(X)(X¹)H in the presence of an olefin. M, R¹, X, X¹, L, and L¹are as described defined in the catalysts section and n is either 1 or 2.

[0054] In preferred embodiments of the alkane method: M is ruthenium; L and L¹ligands are each a phosphine of the formula PR³R⁴R⁵, where R³is a secondary alkyl or cycloalkyl group, and R⁴and R⁵are each aryl, C₁-C₁₀primary alkyl, secondary alkyl, or cycloalkyl groups; X and X¹ligands are each a halogen, benzoate, C₁-C₅carboxylate, C₁-C₅alkyl, C₁-C₅alkoxy, C₁-C₅alkylthio, aryl, or C₁-C₅alkyl sulfonate including chloride, bromide, iodide, CF₃CO₂, CH₃CO₂, CFH₂CO₂, (CH₃)₃CO, (CF₃)₂(CH₃)CO, (CF₃)(CH₃)₂Co, PhO, MeO, EtO, tosylate, mesylate, and trifluoromethanesulfonate; R¹is hydrogen or a substituted or unsubstituted C₁-C₂₀alkyl or aryl wherein the substituted group is selected from a group consisting of aryl, halogen, hydroxy, amino, nitro, C₁-C₅alkyl, C₁-C₅alkoxy, and C₂-C₅alkoxycarbonyl; and the olefin is one which does not readily undergo metathesis reactions or regenerate the same species upon metathesis.

[0055] In especially preferred embodiments: L and L¹ligands are each —P(cyclohexyl)₃, —P(cyclopentyl)₃, or —P(isopropyl)₃; X and X¹ligands are each a halogen; R¹substituent is an substituted or an unsubstituted aromatic hydrocarbon wherein the substituted group is selected from the group consisting of chloride, bromide, iodide, fluoride, —NO₂, —NMe₂, methoxy, and methyl; and the olefin is cyclohexene or styrene.

[0056] In the most preferred embodiments: L and L¹ligands are each either —P(cyclohexyl)₃or —P(cyclopentyl)₃; X and X¹ligands are each chloride; R¹substituent is a substituted or unsubstituted phenyl wherein the substituted group is selected from the group consisting of chloride, bromide, iodide, fluoride, —NO₂, —NMe₂, methoxy, and methyl; and the olefin is cyclohexene.

[0057] As stated previously, it is preferred that the olefin selected for use in this synthetic route is one which does not readily undergo metathesis. When a metathesis active olefin such as ethylene is used, the expected product may not be generated in high yields due to a potential metathesis reaction between the olefin and the product catalyst. For example, when Ru(H)₂(H₂)₂(PCy₃)₂was reacted with either PhCHCl₂or Cl₂CHCO₂Me in the presence of ethylene, instead of the expected benzylidene and ester carbene, a methylidene complex was formed. Observations of the carbene proton resonances of the intermediates (δ=20.59 and 20.15 respectively) as well as the formation of styrene and methyl methacrylate confirm that this is due to the subsequent metathesis reaction of ethylene with the resulting benzylidene and ester carbene.

[0058] However, this subsequent metathesis reaction is substantially eliminated when a less active olefin is used such as cyclohexene. For example, when Ru(H)₂(H₂)₂(PCy₃)₂was reacted with PhCHCl₂, Cl₂CHCO₂Me or CH₂Cl₂in the presence of cyclohexene, the corresponding carbenes were formed in good yield. When these reactions were monitored by ³¹P NMR using triphenylphosphine oxide as the internal standard, the NMR experiments showed that these conversions were essentially quantitative.

[0059] One version of this embodiment of the invention may be summarized in Reaction Scheme 2, below.

[0060] This embodiment includes a process for synthesizing a compound of the formula

[0061] which comprises the step of contacting a compound of the formula

[0062] with a compound of the formula

[0063] wherein M, X, X¹, L, and L¹are as previously defined in the catalysts section.

[0064] Alternatively, the alkyne may be of the general formula, R¹⁷C≡CCR¹²R¹³R′, wherein R′ is hydroxyl. In this variation, the alkyne is reacted with the dihydrogen complex as above but then subsequently reacted with HX to form the above described catalyst. However, in another variation of this reaction scheme, when R′ is hydrogen or a C₁-C₂₀alkyl, the method produces a catalyst of the general formula, (X)(X¹)(L)(L¹)M═C(R¹⁷)(CH₂CR¹²R¹³R′).

[0065] In either version, the remaining variables are n which is either 1 or 2; R¹⁷which is hydrogen, aryl or C₁-C₁₈alkyl; and R¹²and R¹³which are each hydrogen or one of the following substituent groups: C₁-C₁₈alkyl, C₂-C₁₈alkenyl, C₂-C₁₈alkynyl, aryl, C₁-C₁₈carboxylate, C₁-C₁₈alkoxy, C₂-C₁₈alkenyloxy, C₂-C₁₈alkynyloxy, aryloxy, C₂-C₁₈alkoxycarbonyl, C₁-C₁₈alkylthio, C₁-C₁₈alkylsulfonyl and C₁-C₁₈alkylsulfinyl; wherein the substituent group may be substituted with one or more groups selected from C₁-C₅alkyl, C₁-C₅alkoxy, and aryl. When the substitute aryl group is phenyl, it may be further substituted with one or more groups selected from a halogen, a C₁-C₅alkyl, or a C₁-C₅alkoxy. Moreover, the R¹²and R¹³substituent groups may further include one or more functional groups selected from hydroxyl, thiol, thioether, ketone, aldehyde, ester, ether, amine, imine, amide, nitro, carboxylic acid, disulfide, carbonate, isocyanate, carbodiimide, carboalkoxy, carbamate, and halogen.

[0066] In preferred embodiments of the alkyne method: M is ruthenium; L and L¹ligands are each a phosphine of the formula PR³R⁴R⁵, where R³is a secondary alkyl or cycloalkyl group, and R⁴and R⁵are each aryl, C₁-C₁₀primary alkyl, secondary alkyl, or cycloalkyl groups; X and X¹ligands are each a halogen, benzoate, C₁-C₅carboxylate, C₁-C₅alkyl, C₁-C₅alkoxy, C₁-C₅alkylthio, aryl, or C₁-C₅alkyl sulfonate including chloride, bromide, iodide, CF₃CO₂, CH₃CO₂, CFH₂CO₂, (CH₃)₃CO, (CF₃)₂(CH₃)CO, (CF₃)(CH₃)₂CO, PhO, MeO, EtO, tosylate, mesylate, and trifluoromethanesulfonate; R¹²and R¹³are each substituted or unsubstituted C₁-C₁₈alkyl or aryl wherein the substituted group is selected from a group consisting of aryl, halogen, hydroxy, amino, nitro, C₁-C₅alkyl, C₁-C₅alkoxy, and C₂-C₅alkoxycarbonyl; and R¹⁷is hydrogen or methyl.

[0067] In especially preferred embodiments: L and L¹ligands are each —P(cyclohexyl)₃, —P(cyclopentyl)₃, or —P(isopropyl)₃; X and X¹ligands are each a halogen; R¹²and R¹³are each substituted or unsubstituted aromatic hydrocarbon wherein the substituted group is selected from the group consisting of chloride, bromide, iodide, fluoride, —NO₂, —NMe₂, methoxy, and methyl; and R¹⁷is hydrogen.

[0068] In the most preferred embodiments: L and L¹ligands are each either —P(cyclohexyl)₃or —P(cyclopentyl)₃; X and X¹ligands are each chloride; R¹²and R¹³are each substituted or unsubstituted phenyl or wherein the substituted group is selected from the group consisting of chloride, bromide, iodide, fluoride, —NO₂, —NMe₂, methoxy, and methyl; and R¹⁷is hydrogen.

[0069] This embodiment of the invention is an extremely efficient method for synthesizing the above described ruthenium and osmium vinyl alkylidene catalysts in essentially a one pot synthesis. Because the metal complex need not be isolated, it may be generated in situ and then subsequently reacted with a substituted alkyne to form the desired product.

[0070] In addition to the ease of synthesis, the embodiment also results in high product yields. For example, the hydrido chloride complex Ru(H)(Cl)(H₂)(PCy₃)₂reacts rapidly with commercially available 3-chloro-3-methyl-1-butyne in methylene chloride to form the carbene complex Ru(Cl)₂(PCy₃)₂(═CH—CH═Me₂) in 95.2% isolated yield. When this reaction was monitored by ¹H NMR, it was found that the reaction is completed in less than ten minutes, even at −30° C. At this temperature, integration against an internal standard reveals that the yield is approximately 99.5%.

[0071] Reactions with other alkynes, especially propargylic halides, were found to react similarly. Ruthenium carbenes Ru(Cl₂)(PCy₃)₂(═CH—CH═(CH₂)₅) and Ru(Cl₂)(PCy₃)₂(═CH—CH═CHPh) were formed from the corresponding alkynes in essentially quantitative yields, although a trace of the ruthenium (IV) complex, Ru(H)₂(Cl)₂(PCy₃)₂was formed as a byproduct. Interestingly, the amount of the byproduct increased as the steric bulk of the alkyne decreased. For example, the monomethyl substituted HC≡CCH(CH₃)Cl formed the carbene product Ru(Cl)₂(PCy₃)₂(═CH—CH═Me) and the byproduct Ru(H)₂(Cl)₂(PCy₃)₂in an 8:1 ratio, and HC≡CCH2Cl formed the carbene product Ru(Cl)₂(PCy₃)₂(═CH—CH═CH₂) and the byproduct in a 0.8:1 ratio.

[0072] Changing X also affected the amount of the byproduct formed. For example, the dimethyl-substituted propargyl bromide, HC≡CC(Me)₂Br gives 30:1 of the expected mixed halogen carbene RuClBr(PCy₃)₂(═CH—CH═CMe₂) to the mixed halogen Ru(IV) species RuClBr(H)₂(PCy₃)₂which is substantially different than from the greater than 200:1 ratio seen with the corresponding chloride, HC≡CC(Me)₂Cl. As a result, tertiary propargylic halide, especially tertiary propargylic chlorides are most preferred.

[0073] Moreover, ratio of carbene to Ru(IV) byproduct can be improved dramatically if the solvent is changed from dichloromethane to benzene or toluene. By switching solvents, the 8:1 and 0.8:1 product to byproduct ratios of HC≡CCH(CH₃)Cl and HC≡CCH₂Cl were improved to 30:1 and 37:1 respectively.

[0074] When L and L¹groups are triaryl phosphines, Reaction Scheme 2 may be modified by replacing a dihydrogen species in the starting complex with a third phosphine ligand. The resulting hydrido complex will be of the form M(H)(Cl)(H₂)LL¹L²or M(H)(Cl)LL¹L²depending on the starting dihydrogen species. In all other respects, M, X, X¹, R¹², R¹³, and R¹⁷are as described above. Reaction Scheme 2A shows one version of this embodiment.

[0075] This embodiment of the invention may be summarized in Reaction Scheme 3, below.

[0076] This embodiment includes a process for synthesizing a compound of the formula

[0077] This process comprises the step of contacting a compound of the formula

[0078] with a compound of the formula

[0079] M, X, X¹, L, and L¹are as described defined in the catalysts section; n is either 1 or 2; and R¹⁴, R¹⁵, and R¹⁶are each is hydrogen or one of the following substituent groups: C₁-C₁₉alkyl, C₂-C₁₉alkenyl, C₂-C₁₉alkynyl, aryl, C₁-C₁₉carboxylate, C₁-C₁₉alkoxy, C₂-C₁₉alkenyloxy, C₂-C₁₉alkynyloxy, aryloxy, C₂-C₁₉alkoxycarbonyl, C₁-C₁₉alkylthio, C₁-C₁₉alkylsulfonyl and C₁-C₁₉alkylsulfinyl; wherein the substituent group may be substituted with one or more groups selected from C₁-C₅alkyl, C₁-C₅alkoxy, and aryl. When the substitute aryl group is phenyl, it may be further substituted with one or more groups selected from a halogen, a C₁-C₅alkyl, or a C₁-C₅alkoxy. Moreover, the R¹⁴, R¹⁵, and R¹⁶substituent groups may further include one or more functional groups selected from hydroxyl, thiol, thioether, ketone, aldehyde, ester, ether, amine, imine, amide, nitro, carboxylic acid, disulfide, carbonate, isocyanate, carbodiimide, carboalkoxy, carbamate, and halogen.

[0080] In preferred embodiments of the alkene method: M is ruthenium; L and L¹ligands are each a phosphine of the formula PR³R⁴R⁵, where R³is a secondary alkyl or cycloalkyl group, and R⁴and R⁵are each aryl, C₁-C₁₀primary alkyl, secondary alkyl, or cycloalkyl groups; X and X¹ligands are each a halogen, benzoate, C₁-C₅carboxylate, C₁-C₅alkyl, C₁-C₅alkoxy, C₁-C₅alkylthio, aryl, or C₁-C₅alkyl sulfonate including chloride, bromide, iodide, CF₃CO₂, CH₃CO₂, CFH₂CO₂, (CH₃)₃CO, (CF₃)₂(CH₃)CO, (CF₃)(CH₃)₂CO, PhO, MeO, EtO, tosylate, mesylate, and trifluoromethanesulfonate; R¹⁴and R¹⁵are each substituted or unsubstituted C₁-C₁₈alkyl or aryl wherein the substituted group is selected from a group consisting of aryl, halogen, hydroxy, amino, nitro, C₁-C₅alkyl, C₁-C₅alkoxy, and C₂-C₅alkoxycarbonyl; and R¹⁶is hydrogen.

[0081] In especially preferred embodiments: L and L¹ligands are each —P(cyclohexyl)₃, —P(cyclopentyl)₃, or —P(isopropyl)₃; X and X¹ligands are each a halogen; R¹⁴and R¹⁵are each substituted or unsubstituted aromatic hydrocarbon wherein the substituted group is selected from the group consisting of chloride, bromide, iodide, fluoride, —NO₂, —NMe₂, methoxy, and methyl; and R¹⁶is hydrogen.

[0082] In the most preferred embodiments: L and L¹ligands are each either —P(cyclohexyl)₃or —P(cyclopentyl)₃; X and X¹ligands are each chloride; R¹⁴and R¹⁵are each substituted or unsubstituted phenyl or wherein the substituted group is selected from the group consisting of chloride, bromide, iodide, fluoride, —NO₂, —NMe₂, methoxy, and methyl; and R¹⁶is hydrogen.

[0083] When L and L¹groups are triaryl phosphines, Reaction Scheme 3 may be modified by replacing a dihydrogen species in the starting complex with a third phosphine ligand. The resulting hydrido complex will be of the form M(H)(Cl)(H₂)LL¹L²or M(H)(Cl)LL¹L²depending on the starting dihydrogen species. In all other respects, M, X, X¹, R¹⁴, R¹⁵, and R¹⁶are as described above. Reaction Scheme 3A shows one version of this embodiment.

[0084] Because the alkene route reactions appears to be less efficient than the other two methods, the alkane route is generally the preferred method when non-vinyl alkylidene catalyst are to be synthesized. For example, Ru(H)(Cl)(H₂)(PCy₃)₂reacts with vinyl chloride to give the expected carbene Ru(Cl)₂(PCy₃)₂(═CHCH₃), the methylidene complex Ru(Cl)₂(PCy₃)₂(═CH₂), and the ruthenium (IV) byproduct Ru(H)₂(Cl)₂(PCy₃)₂. The methylidene complex is a result of a subsequent cross metathesis reaction between the intended carbene product and vinyl chloride (which also results in the formation of 1-chloropropene). However, even when the total carbene products are taken into account, the ratio of carbene to Ru(IV) byproduct is a modest 2.1:1. Unlike the alkyne route, increasing the steric bulk at the alkene's β-carbon (to suppress β-addition), did not improve the carbene yield.

[0085] Alternative Synthesis for Ru(X)₂(L)₂(═CHR¹):

[0086] In this method, Ru(1,5-cyclooctadiene)(cyclooctatriene) (hereinafter referred to as “Ru(COD)(COT)”) is used instead of the dihydrogen complex to synthesize catalysts of the general formula Ru(X)₂(L)₂(═CHR¹) wherein:

[0087] R¹is as previously defined in the catalyst section;

[0088] X is a halogen; and,

[0089] L is a phosphine of the formula PR³R⁴R⁵, where R³is a secondary alkyl or cycloalkyl group, and R⁴and R⁵are independently selected from aryl, C₁-C₁₀primary alkyl, secondary alkyl, or cycloalkyl groups. In preferred embodiments, X is chloride and L is P(cyclohexyl)₃, P(cyclopentyl)₃, or P(isopropyl)₃. R¹CHX₂is added to a solution of Ru(COD)(COT) in the presence of phosphine, L, in a suitable solvent at room temperature to generate the product, Ru(X)₂(L)₂(═CHR¹). Illustrative examples of suitable solvents include but are not limited to toluene, benzene and dichloromethane.

[0090] The general mechanism of reaction involves two steps: the oxidative addition of the alkyl dihalide to the Ru(0) species followed by an α-halide elimination. An illustrative example of this method is shown in Reaction Scheme 4 which results in a 50% product yield of RuCl₂(PCy₃)₂(═CHPh).

[0091] However, this synthetic route presents two potential limitations. The first is that although good yields have been reported, Ru(COD)(COT) is difficult and tedious to synthesize. The second is that the formation of phosphonium salts, such as PCy₃CHClR¹⁺Cl⁻ when X=Cl and L=PCy₃, may potentially limit the viability of this route for some carbene catalysts. For example, while RuCl₂(PCy₃)₂(═CHPh) and RuCl₂(PCy₃)₂(═CH₂) may be synthesized in this manner, RuCl₂(PCy₃)₂(═CHCO₂Me) cannot be synthesized using Cl₂CHCO₂Me because of the formation of the phosphonium salt, [Cy₃PCHClCHCO₂Me]⁺Cl⁻ as a side reaction.

[0092] Alternative Synthesis for RuCl2(PCy3)2(═CHPh):

[0093] This alternative route is a variation of the alkane route that was previously described and takes advantage of a potential metathesis reaction between the olefin used in the reaction and the carbene product. First, RuCl₂(PCy₃)₂(═CHCO₂Me) is formed by reaction Ru(H)₂(H₂)₂(PCy₃) with Cl₂CHCO₂Me in the presence of the olefin, styrene, in an application of the above described alkane reaction. The formed carbene RuCl₂(PCy₃)₂(PCy₃)(═CHCO₂Me) undergoes a subsequent metathesis reaction with styrene to produce the final product RuCl₂(PCy₃)₂(═CHPh).

[0094] Synthesis of Ru(H)₂(H₂)₂(PCy₃)₂.

[0095] In general, unless explicitly noted otherwise, all solvents used are degassed prior to use. [RuCl₂(COD)]_x(6.0 g, 21.43 mmol), PCy₃(12.0 g, 42.86 mmol), and NaOH (7.2 g) were placed in a 500 mL Fisher-Porter bottle. [RuCl₂(COD)]_xis a polymeric complex produced from the reaction of RuCl₃with COD. Degassed sec-butyl alcohol (250 mL) was added, and the suspension was pressurized under H₂(2 atm) and heated at 90° C. The system was repressurized several times, an indication of H₂uptake. The reaction mixture was stirred overnight. The system was allowed to cool to room temperature under H₂pressure. A pale yellow crystalline precipitate was obtained. All of the following manipulations were carried out under H₂pressure. Water (30 mL) was added to the resulting mixture, and the mixture was filtered though a glass frit filter. The filtrate was washed twice with water (30 mL portions) and with methanol (twice with 20 mL portions. The solid was dried under a H₂stream. 11.8 g (83% yield) of a pale yellow crystalline compound was obtained. The NMR spectra of this product were identical to those previously reported in the literature for Ru(H)₂(H₂)₂(PCy₃)₂.

[0096] Synthesis of RuCl₂(PCy₃)₂(═CHPh).

[0097] To a suspension of Ru(H)₂(H₂)₂(PCy₃)₂(1.0 g, 1.50 mmol) in pentane (40 mL), cyclohexene (1.5 mL, 14.80 mmol) was added. After 2 minutes, a yellow solution is obtained, and after 15 minutes, a pale yellow precipitate is formed. The reaction mixture was stirred for 1 hour. The volatiles were removed under vacuum. Pentane was added to the solid. Addition of PhCHCl₂(0.4 mL, 3.11 mmol) led to the formation of a red solution, which was stirred for 45 minutes. The solvent was evaporated, and the residue was washed with cold methanol (three times with 10 mL portions). 0.75 g (61% yield) of a purple solid was obtained whose NMR spectra were identical to the compound RuCl₂(PCy₃)₂(═CHPh).

[0098] Synthesis of RuCl₂(PCy₃)₂(═CH₂) and RuCl₂(PCy₃)₂(═CHCO₂Me).

[0099] RuCl₂(PCy₃)₂(═CH₂) and RuCl₂(PCy₃)₂(═CHCO₂Me) were prepared in an analogous manner as above except that Cl₂CH₂and Cl₂CHCO₂Me were added as the dihalo compounds respectively. In the case of the synthesis of RuCl₂(PCy₃)₂(═CH₂), because the reaction is slower as monitored by NMR, the reaction mixture was stirred overnight after the addition of Cl₂CH₂.

[0100] Selective spectroscopic data for RuCl₂(PCy₃)₂(═CHCO₂Me): ¹H NMR (300 MHz, C₆D₆: δ 20.15 (s, Ru=CH), 3.53 (s, CO2CH3); ¹³C NMR (125.71, CD₂Cl₂, −30° C.) δ 276.37 (t, J(P,C)=5.1 Hz, Ru=CH), 178.69 (s, CO₂Me), 50.84 (s, CO₂CH₃); ³¹P (161.9 MHz, C₆D₆) δ 38.66 (s, PCy₃); IR (Nujol) ν 1721 cm⁻¹(C═O—(ester)).

[0101] Ru(H)₂(H₂)₂(PCy₃)₂+styrene +α,α-dichlorotoluene.

[0102] Styrene (0.2 mL, 1.7 mmol) was added to a solution of Ru(H)₂(H₂)₂(PCy₃)₂(0.54 g; 0.77 mmol) in toluene (20 mL). After 15 min, α,α-dichlorotoluene (0.1 mL) was added to the resulting deep red solution. The reaction mixture was stirred for 45 min. The solvent was removed and the residue washed with methanol and acetone affording the isolation of a purple solid, identified as Ru(═CHPh)Cl₂(PCy₃)₂by NMR. Yield 25%.

[0103] Isolation and utility of an alkane-reaction intermediate where the olefin is cyclohexene: Ru(cyclohexene)₂(H₂)(PCy₃)₂.

[0104] Cyclohexene (5 mL was added to Ru(H₂)(H₂)₂(PCy₃)₂(1.1 g; 1.65 mmol). The formation of a red solution was observed and immediately a pale yellow solid precipitated out. Pentane was added (20 mL) and the suspension was stirred for 2 h. The solid was isolated by filtration. Yield: 81%. ₁H in C₆D₆: −5. (br s, 2H, H₂), 1.2-2.0 (m, 66H, PCy₃), 3.0 (s, 1H, CH_olefin), 20.1 ppm; ³¹P{¹H} 59 ppm (s).

[0105] Addition of R¹CHX¹X to this intermediate, Ru(cyclohexene)₂(H₂)(PCy₃)₂results in the ruthenium catalyst, RuX¹X(PCy₃)₂(R¹). As a result, the specific intermediate, Ru(cyclohexene)₂(H₂)(PCy₃)₂, or any intermediate of the general form, Ru(olefin)₂(H₂)(PCy₃)₂, may replace Ru(H)₂(H₂)₂(PCy₃)₂and the olefin in the alkane reaction route.

[0106] For example, Ru(═CHPh)Cl₂(PCy₃)₂was synthesized by adding α,α-dichlorotoluene (5 μL) to a solution of Ru(cyclohexene)₂(H₂)(Cy₃P)₂(20 mg; 2.68·10−2 mmol) in C₆D₆(0.5 mL) The solution turned deep red and the ¹H and ³¹P{¹H} NMR spectra showed the quantitative conversion to Ru(═CHPh)Cl₂(PCy₃)₂. Similarly, Ru(═CHCOOMe)Cl₂(PCy₃)₂was synthesized by adding methyl dichloroacetate (5 μL) to a solution of Ru(cyclohexene)₂(H₂)(PCy₃)₂(20 mg; 2.68·10−2 mmol) in C₆D₆(0.5 mL). The solution turned violet and the ¹H and ³¹P NMR spectra showed the quantitative conversion to Ru(═CHCOOMe) Cl₂(PCy₃)₂. ¹H in C₆D₆: 1.2-2.7 (m, 66H, PCy₃), 3.5 (s, 3H, COOCH₃), 20.1 ppm (s, CH carbene unit); ³¹P{¹H} in C₆D₆38 ppm (s, PCy₃).

[0107] Synthesis of Ru(H)(Cl)(H₂)₂(PCy₃)₂.

[0108] [RuCl₂(COD)]_x(4.00 g, 14.28 mmol) and tricyclohexylphosphine (8.46 g of 97% from Strem, 29.26 mmol) were placed in a 500 ml, high pressure system equipped with a pressure gauge. To this system, 200 mL of degassed sec-butanol and triethylamine (1.99 mL, 14.28 mmol) were added. The system is then placed under vacuum, and purged with hydrogen. After purging, the system is pressurized with 1.5 atm of hydrogen, sealed, and heated to 80° C. for a total of 20 hours. When the pressure dropped below an atmosphere the system was cooled and re-pressurized, approximately every 20-30 minutes for the first several hours.

[0109] Generation of Ru(H) (Cl) (H₂)₂(PCy₃)₂can also be accomplished in a suitably sized, thick walled teflon-valved Strauss flask. Depending on the scale of the reaction and the size of the flask, the system is re-pressurized with hydrogen gas after several hours. Alternatively, the reaction can be carried out by bubbling H₂gas at atmospheric pressure.

[0110] Isolation of the air-sensitive orange solid was accomplished by allowing the system to cool to room temperature and adding a volume (200 mL) of degassed methanol to insure complete precipitation. The solid was filtered, washed with methanol (3×, 50 mL, and dried in vacuo to give 9.26 g, 93% of Ru(H)(Cl)(H₂)₂(PCy₃)₂.

[0111] Synthesis of RuCl₂(PCy₃)₂(═CH—CH═CMe₂).

[0112] Method A—alkyne route:

[0113] Ru(H)(Cl)(H2)(PCy3)2 (1.00 g, 1.43 mmol) under an inert atmosphere is dissolved in 30 mL of dichloromethane cooled to −30° C., and 3-chloro-3-methyl-1-butyne (170 μL, 1.5 mmol) is added. The solution instantly turns dark red-purple, and is allowed to stir for fifteen minutes before removing the flask from the cooling bath and concentrating to a viscous oil. Degassed methanol (20 mL) is added to precipitate the purple solid, which is then washed with methanol (3×, 10 mL) and dried to give 1.09 g or approximately 95.2% yield of the carbene.

[0114] Selected NMR data (CD₂Cl₂): ¹H:δ 19.26 (d, RuCH, J_HH=11.7 Hz), 7.81 (d, RuCHCH, J_HH=11.7 Hz); ³¹P:δ 36.4 (s, RuPCy₃); ¹³C: δ 288.4 (t, Ru^CH, J_CP=9.6 Hz), 146.9 (s), 133.5 (s).

[0115] NMR studies show that this reaction at −30° C. is extremely clean (no other carbene species) and proceeds to approximately 99%. At room temperature the reaction is less clean (i.e., other presumed and unidentified carbene species are generated in small quantities) but also proceeds in ˜98% yield. Therefore, the use of low temperatures for the generation of this compound should give a slightly easier isolation and higher yield of a pure product. However, the generation of this carbene for use in situ can be done at room temperature with little or no visible effect.

[0116] All other reactions with Ru(H)(Cl)(H₂)(PCy₃)₂described in the description portion of the specification were done in a similar fashion but on a 20 mg scale in 0.5 mL of CD₂Cl₂. Non commercially available alkynes were made following procedures in Preparative Acetylenic Chemistry, L. Brandsma, Elsevier Science Publishers B. V. (Amsterdam, 1988); H. Werner, et al., Chem. Ber.122: 2097-2107 (1989); and K. Hiraki, et al., J. Chem. Soci., Dalton Trans. pp.873-877 (1985), all of which are incorporated herein by reference.

[0117] Method B—triarylphosphine version of the alkyne route 0.24 mL of 3-chloro-3-methyl-1-butyne was added to a −30° C. solution of Ru(H)(Cl)(PPh₃)₃(2.0 g, 1.99 mmoles) in methylene chloride (20 ml). The reaction mixture was stirred for 1.5 hour at 0° C. After the volume was reduced to 1 mL under reduced pressure, 20 mL of pentane was added. The resulting brown solid was isolated by filtration, redissolved in 1 mL of methylene chloride and then was washed twice with 10 mL portions of pentane to yield 1.5 grams (90% yield) of the desired product.

[0118] Method C—in situ generation of Ru(H)(Cl)(H₂)(PCy₃)₂[RuCl₂(COD)]_x(0.500 g, 1.78 mmol) and tricyclohexylphosphine (1.050 g, 3.75 mmol) were placed in a 250 mL thick walled teflon-valved Strauss flask. To this system, 20 mL of degassed sec-butanol is added. The system is then placed under vacuum, purged with hydrogen, sealed, and heated to 80° C. After four hours the system is cooled to room temperature, re-pressurized with hydrogen, and allowed to stir at 80° C. for a further sixteen hours. The system is then cooled to room temperature and one volume of toluene is added. The resulting solution is cooled to −30° C. and 2-methyl-1-buten-3-yne (254 mL, 2.66 mmol) is added. After stirring for one hour the solution is concentrated by half and 50 mL of degassed methanol is added to give a purple solid, isolated as above to give 0.590 g, 41% of RuCl₂(PCy₃)₂(═CH—CH═CMe₂).

[0119] Synthesis of RuCl₂(PCy₃)₂(═CH—CH═CMe₂)—one pot method.

[0120] [RuCl₂(COD)]_x(0.500 g, 1.79 mmol) and tricyclohexylphosphine (1.000 g, 3.58 mmol) were placed in a 500 mL high pressure system equipped with a pressure gauge. To this system, 25 mL of degassed sec-butanol and triethylamine (0.250 mL, 1.79 mmol) were added. After purging with hydrogen, the system was pressurized with 1.5 atm of hydrogen and heated to 80° C. for a total of 20 hours, repressurizing as needed. An orange precipitate, known to be Ru(H)(H₂)₂Cl(PCy₃)₂is observed as well as a slightly brown solution. The apparatus was then cooled to room temperature, and then to 0° C., at which point it was purged with argon. 3-chloro-3-methyl-1-butyne (0.600 mL, 5.3 mmol) is added. Over a period of one hour the orange precipitate turns red-purple, and the reaction is then removed from the ice bath and allowed to stir for one additional hour. Degassed methanol (25 mL) is added to precipitate the purple solid, which is then washed with methanol (3×10 mL) and dried to give 1.35 g, 94.5% of the carbene. Selected NMR data (CD₂Cl₂):¹H:d19.26 (d, RuCH, J_HH=11.7 Hz, 1H), 7.81 (d, RuCHCH, J_HH=11.7 Hz, 1H); ³¹P:d 36.4 (s, RuPCy3); ¹³C: d 288.4 (t, RuCH, J_CP=9.6 Hz), 146.9 (s), 133.5 (s).

[0121] Synthesis of RuCl₂(PⁱPr₃)₂Cl₂Ru(═CH—CH═CMe₂)—one pot method.

[0122] This procedure is identical to the one pot method for the synthesis of RuCl₂(PCy₃)₂(═CH—CH═CMe₂) except that triisopropyl phosphine (0.573 g, 3.58 mmol) is used instead of tricyclohexylphosphine. In this case the intermediate Ru(H)(H₂)₂Cl(PiPr₃)₂is soluble, giving a red-brown solution which is then cooled and to which the 3-chloro-3-methyl-1-butyne is added. The reaction is quite vigorous, with gas evolved immediately and a deep purple precipitate observed. After stirring for thirty minutes the solid is isolated as above to give 1.85 g, 92.5% of the carbene. Selected NMR data (CD₂Cl₂):¹H:d19.38 (d, RuCH, J_HH=11 Hz, 1H), 7.95 (d, RuCHCH, J_HH=11 Hz, 1H), 2.80 (m, PCH(CH₃)₂, 6H), 1.54 and 1.26 (s, RuCHCHC(CH₃)₂, 3H each), 1.23 (dd, P PCH(CH₃)₂, 36H); ³¹P:d 45.8 (s, RuPCy3).

[0123] Synthesis of Poly-dicyclopentadiene using in situ generated catalyst.

[0124] The in situ generation of Ru₂Cl₂(PCy₃)₂(═CH—CH═CMe₂) (hereinafter referred to as the ruthenium carbene catalyst in this example) is accomplished by dissolving 18 mg (0.025 mmol) of Ru(H)(Cl)(H₂)₂(PCy₃)₂in approximately 0.5-1.0 mL of dichloromethane under argon. This solution is cooled to −30° C., at which point 3-chloro-3-methyl-1-butyne (3.5 mL, 0.030 mmol) is added. The solution instantly turns red-purple, and is allowed to stir for fifteen minutes before removing the solvent to give a dark oil. If a solid is desired, the solution can be concentrated and a small amount (<1 mL) of degassed methanol can be added to give a purple solid, which is dried in vacuo (without filtration).

[0125] Polymerizations are done by placing the solution obtained below in a 40° C. oil bath for one hour, and then at least one hour in an oven at 100° C.

[0126] Method A:

[0127] The in situ generated ruthenium carbene catalyst is dissolved in 25 mL of DCPD and poured into a beaker.

[0128] Method B:

[0129] The in situ generated ruthenium carbene catalyst is dissolved in 5 mL of DCPD which contains 40 mg of triphenylphosphine, and allowed to stir under argon. After four hours the solution has become quite viscous and is added to 20 mL of DCPD in a beaker.

[0130] Method C:

[0131] The in situ generated ruthenium carbene catalyst is dissolved in 1 mL of DCPD which contains 40 mg of triphenylphosphine, and allowed to stir under argon. After 17 hours this solution has a slimy, soft gelatin like consistency, which can be dissolved in 4 mL of DCPD before being added to 20 mL DCPD in a beaker.

[0132] Ru(COD)(COT)+2 PCy₃+α,α-dichlorotoluene.

[0133] To a solution of Ru(COD)(COT) (0.11 g; 0.33 mmol) and PCy₃(0.19 g; 0.67 mmol) in 15 mL of toluene was added α, α-dichlorotoluene (50 mL; 0.39 mmol). The reaction mixture was stirred at room temperature for two days. The resulting deep brown solution was evaporated, and the residue was washed with acetone and methanol (twice with 5 mL portions) affording the isolation of a purple solid. The NMR spectra of this product were identical to the compound Ru(═CHPh)Cl₂(PCy₃)₂. Yield: 50%.

[0134] Ru(H)₂(H₂)(PCy₃)₂+styrene+Cl₂CHCO₂Me.

[0135] Styrene (5 mL) was added to a suspension of Ru(H)₂(H₂)₂(PCy₃)₂(3.0 g, 4.50 mmol) in pentane (50 mL). The red solution immediately obtained was stirred for 1 hour, and Cl₂CHCO₂Me (0.9 mL, 8.7 mmol) was then added. The reaction mixture was stirred for 45 minutes. The solvent was removed, and the residue was washed with acetone and methanol (twice with 20 mL portions). A purple solid (2.0 g, 54% yield) was isolated whose NMR data were identical to those of RuCl₂(PCy₃)₂(═CHPH).