Ferrocene-modified ruthenium carbene olefin metathesis catalyst as well as preparation method and application thereof

Abstract

The invention provides a ferrocene modified ruthenium carbene olefin metathesis catalyst as well as a preparation method and application thereof. The ferrocene-modified ruthenium carbene olefin metathesis catalyst has a structure as shown in a formula I: # imgabs0 #, in the formula I, Fc is a ferrocene structure, m is 0-2, n is 1-3, and m + n is 3; x is a solvent ligand, and a is 0 or 1. The ferrocene modified ruthenium carbene olefin metathesis catalyst has the characteristic of high catalytic activity, and can be applied to olefin metathesis reactions including selective synthesis of unsaturated dimethyl octadecanedioate.

Description

Technical Field

[0001] The present invention belongs to the technical field of olefin metathesis catalysts, and particularly relates to a ferrocene-modified ruthenium carbene olefin metathesis catalyst, a preparation method thereof, and an application thereof. Background Art

[0002] Dimethyl unsaturated octadecanedioate is an important chemical raw material, which is widely used in the synthesis of degradable polyester plastics and elastic polymers. There are more than 20 kinds of chemical products extended downstream thereof, all of which have important application values. Therefore, the large-scale industrial preparation technology of dimethyl unsaturated octadecanedioate has always received extensive attention. The selective synthesis of dimethyl unsaturated octadecanedioate is based on the ethylolysis reaction of methyl oleate to establish a new technology. The ethylolysis reaction of methyl oleate is a special case of olefin metathesis reaction. Olefin metathesis reaction is an effective method for constructing complex molecules by carbon-carbon double bond recombination. This method has the advantages of simplicity, rapidity, high efficiency, and good atom economy, and has important application prospects in the fields of biology, medicine, and organic synthesis. The smooth progress of olefin metathesis reaction depends on the research and development of efficient olefin metathesis catalysts. Designing catalysts with good stability, high activity, and low price has become a research hotspot in the field of olefin metathesis.

[0003] At present, due to excellent stability and reaction activity, Ru carbene olefin metathesis catalysts are the main commercially available catalyst types. Ru olefin metathesis catalysts are complexes with Ru metal as the catalytic active center, and can be mainly divided into Grubbs-type catalysts and Hoveyda-Grubbs-type catalysts. Almost all of the currently studied Ru olefin metathesis catalysts are obtained by various modifications based on these two types of catalysts. Grubbs-type catalysts are further divided into Grubbs I, Grubbs II, and Grubbs III type catalysts, and their structural general formula is [Cl2(L)(L’)Ru=C(H)R]. Grubbs I catalyst is a widely used catalyst. The synthesis process of this type of catalyst is simple, and its structure is very stable. It can even be exposed to air for a long time without decomposition. Moreover, the functional group applicability of the catalyst is very good, and it can be used for the metathesis reaction of olefins with various functional groups. It has low requirements for reaction conditions and can catalyze in the presence of impurities such as oxygen and water. However, this type of catalyst is not suitable for substrates with amino groups, and primary amines in the reaction system will cause the catalyst to be poisoned and inactivated. The development of Grubbs I catalyst makes up for the deficiencies of molybdenum and tungsten catalysts, and greatly expands the application scope of olefin metathesis reaction.

[0004] In the research on the first-generation catalyst by the Grubbs group, it was found that during the initiation stage of the catalyst, a phosphine ligand dissociates from the Ru metal center to form a catalytically active metal intermediate. Therefore, Grubbs et al. designed to use an N-heterocyclic carbene ligand to replace one phosphine ligand in the first-generation catalyst, accelerating the dissociation of another phosphine ligand during the catalytic initiation stage, thereby improving the catalytic activity of the catalyst. This newly obtained catalyst is called the Grubbs II catalyst. It has more advantages compared with the first-generation catalyst. For example, it can catalyze RCM reactions of diene substrates with di-, tri-, and tetra-substitutions, requires less catalyst amount for the reaction, and has a shorter reaction time. The Grubbs III catalyst is obtained by stirring the Grubbs II catalyst in pyridine. The pyridine in the third-generation catalyst is more easily dissociated than the phosphine ligand in the second-generation catalyst, so it has a higher initiation rate and is more easily replaced by other ligands. Therefore, the Grubbs III catalyst is often used to synthesize catalysts with new structures.

[0005] Hoveyda et al. prepared a phenoxy-chelated ruthenium carbene complex based on the Grubbs I catalyst. The catalyst has obvious activity and good stability and can be used for the large-scale preparation of various olefin compounds. Moreover, this catalyst is recyclable and can be recovered by simple chromatography after the reaction. This is the first recyclable olefin metathesis catalyst, which can efficiently catalyze homogeneous olefin metathesis reactions and shows no loss of activity during repeated use. This catalyst was later called the Hoveyda-Grubbs I catalyst. Subsequently, based on the Grubbs II catalyst, the Hoveyda group successfully developed the Hoveyda-Grubbs II catalyst. Compared with other previous ruthenium catalysts, this type of catalyst has a higher initiation rate and stability (stable in air), and the reaction conditions are relatively mild, and high yields can be obtained at room temperature. It also has high catalytic activity for electron-deficient olefins such as acrylonitrile and fluoroolefins. Most importantly, this type of catalyst can be immobilized by chemical and physical methods and then recovered, and the recovery efficiency is very high.

[0006] However, in the ethenolysis reaction of methyl oleate, these types of catalysts cannot meet the requirements of industrialization. The Grubbs research group discovered a new type of mono-nitrogen cyclic carbene (CAAC) ruthenium catalyst. This catalyst changes the N-heterocyclic carbene ligand of traditional catalysts, replacing one of the nitrogen atoms with a carbon atom, which has great advantages for such reactions and has extremely high conversion rates. However, the synthesis method of this catalyst is relatively cumbersome, the production cost is high, and it is not currently on the market, so it is not an ideal catalyst for industrial production. However, among several traditional commercially available catalysts, the Grubbs I catalyst has a very high selectivity for the formation of 9-decene and methyl 9-decenoate from the ethenolysis product of methyl oleate, reaching over 99%, which is much higher than those of Grubbs II, Grubbs III, and Hoveyda-Grubbs II catalysts. Although the Hoveyda-Grubbs I catalyst also has a high selectivity for 9-decene and methyl 9-decenoate (>99%), its catalytic activity is much lower than that of the Grubbs I catalyst. Also, because the Grubbs I catalyst, as the first-generation olefin metathesis catalyst, has a simple production process and a low synthesis cost, it is an ideal catalyst for the industrial ethenolysis of methyl oleate.

[0007] The literature “(a) Love, J.A.; Morgan, J.P.; Trnka, T.M.; Grubbs, R.H. “A practical and highly active ruthenium-based catalyst that effects the cross metathesis of acrylonitrile”. Angew. Chem., Int. Ed., 2002, 41(21), 4035 - 4037; (b) Trnka, T.M.; Morgan, J.P.; Sanford, M.S.; Wilhelm, T.E.; Scholl, M.; Choi, T.-L.; Ding, S.; Day, M.W.; Grubbs, R.H. “Synthesis and activity of ruthenium alkylidene complexes coordinated with phosphine and N-heterocyclic carbene ligands”. J. Am. Chem. Soc., 2003, 125, 2546 - 2558” discloses the following: replacing one PCy3 in GI with a N-heterocyclic carbene (NHC) ligand to obtain the Grubbs II catalyst significantly improves the stability of the ruthenium carbene catalyst and its catalytic activity for general olefin metathesis reactions; however, this technology requires the introduction of NHC ligands, increasing the catalyst cost, being expensive, and not suitable as an industrial catalyst; it has low catalytic efficiency for the ethenolysis of methyl oleate and low selectivity for products.

[0008] The literature "(a) Hoveyda, A. H.; Kingsbury, J.; Garber, S.; Gray, B. L.; Garber, Steven; Gray, Brian Lawrence; Fourkas, J. T. "Recyclable metathesis catalysts". PATENT: WO2002014376, 2001 - 08 - 09; (b) Gessler, S.; Randl, S.; Blechert, S. "Synthesis and metathesis reactions of a phosphine - free dihydroimidazole carbene ruthenium complex". Tetrahedron Letters, 2000, 41(51), 9973 - 9976" discloses the following: The Py ligand replaces PCy3 in Grubbs II to obtain the Grubbs III catalyst. The stability of the ruthenium carbene catalyst and its catalytic activity for most olefin metathesis reactions are improved, and the reaction rate of the metathesis reaction is increased; however, this catalyst is obtained based on Grubbs II, is expensive, and requires multiple - step synthesis; its catalytic efficiency for the ethenolysis of methyl oleate is low, and the product selectivity is 9 - octadecene and dimethyl 9 - octadecenoate.

[0009] The literature "Kingsbury, J. S.; Harrity, J. P. A.; Hoveyda, A. H. "A recyclable Ru - based metathesis catalyst". J. Am. Chem. Soc., 1999, 121, 791 - 799" discloses the following: The introduction of a chelating isopropoxy ligand to replace one PCy3 in G I gives the Hoveyda - Grubbs I catalyst, which improves the stability and catalytic activity of the ruthenium carbene catalyst; however, this catalyst has more synthesis steps and expensive raw materials; its catalytic activity for the ethenolysis of methyl oleate is relatively low.

[0010] The literature "(a) Hoveyda, A. H.; Kingsbury, J.; Garber, S.; Gray, B. L.; Garber, Steven; Gray, Brian Lawrence; Fourkas, J. T. "Recyclable metathesis catalysts". PATENT: WO2002014376, 2001-08-09; (b) Gessler, S.; Randl, S.; Blechert, S. "Synthesis and metathesis reactions of a phosphine-free dihydroimidazole carbene ruthenium complex". Tetrahedron Letters, 2000, 41(51), 9973-9976" discloses the following: Replacing PCy3 in H-GI with an NHC ligand gives the Hoveyda-Grubbs II catalyst, which improves the stability of the ruthenium carbene catalyst and the catalytic activity for most olefin metathesis reactions; however, the synthesis steps of this catalyst are numerous and the raw materials are expensive; its catalytic activity for the ethenolysis of methyl oleate is low and the selectivity for the product is poor.

[0011] The literature "Anderson, D. D. R.; Ung, T.; Mkrtumyan, G.; Bertrand, G.; Grubbs, R. H.; Schrodi, Y. "Kinetic selectivity of olefin metathesis catalysts bearing cyclic(alkyl)(amino)carbenes". Organometallics, 2008, 27(4), 563-566" discloses the following: Replacing the NHC in Grubbs II with a CAAC ligand improves the stability of the ruthenium carbene catalyst and the reactivity for the ethenolysis of methyl oleate; however, the synthesis steps of the CAAC ligand are rather cumbersome and the catalyst is expensive.

[0012] The document "Gawin, R.; Tracz, A. J.; Krajczy, P. "Novel ruthenium complexes, methods of their preparation and application thereof in olefin cross metathesis". World Intellectual Property Organization, WO 2022 / 038121, 2022-02-24" discloses the following: Replacing the NHC in Hoveyda-Grubbs II with a CAAC ligand improves the stability of the ruthenium carbene catalyst and the ethyleneolysis reaction activity towards methyl oleate; however, the synthesis steps of the CAAC ligand are relatively cumbersome and the catalyst is expensive. Summary of the Invention

[0013] In order to solve the above problems, the object of the present invention is to provide a ferrocene-modified ruthenium carbene olefin metathesis catalyst, a preparation method and an application thereof. The ferrocene-modified ruthenium carbene olefin metathesis catalyst has the characteristics of high catalytic activity and can be applied to olefin metathesis reactions including the selective synthesis of dimethyl unsaturated octadecanedioate.

[0014] In order to achieve the above object, the present invention provides a ferrocene-modified ruthenium carbene olefin metathesis catalyst, which has the structure shown in Formula I:

[0015]

[0016] In Formula I, Fc is a ferrocene structure, m is 0-2, n is 1-3, and m + n = 3; X is a solvent ligand, and a is 0 or 1. Wherein, Cy represents cyclohexyl.

[0017] According to a specific embodiment of the present invention, preferably, n is 1 or 3.

[0018] According to a specific embodiment of the present invention, preferably, X is selected from pyridine.

[0019] The present invention also provides a preparation method of the above-mentioned ferrocene-modified ruthenium carbene olefin metathesis catalyst, which includes the following steps: Under the atmosphere of a protective gas, PCy m Fc n is mixed with (PCy₃)(Py)₂Cl₂Ru═CHPh in a solvent for reaction to obtain the ferrocene-modified ruthenium carbene olefin metathesis catalyst.

[0020] According to a specific embodiment of the present invention, preferably, in the preparation method of the above catalyst, the reaction time is 0.5 - 5 h, more preferably 0.5 - 2 h; the reaction temperature is 0 - 50 °C, more preferably 0 - 30 °C.

[0021] According to a specific embodiment of the present invention, preferably, in the preparation method of the above catalyst, the solvent includes dichloromethane.

[0022] According to a specific embodiment of the present invention, preferably, in the preparation method of the above catalyst, the PCy m Fc n and (PCy3)(Py)2Cl2Ru=CHPh have a molar ratio of 1:1 - 5:1, more preferably 1:1 - 3:1.

[0023] According to a specific embodiment of the present invention, preferably, the PCy m Fc n The preparation method thereof includes the following steps: under the atmosphere of a protective gas, ferrocene is mixed in a solvent, cooled to 0 °C, then tert-butyllithium is added dropwise, reacted for 0.5 - 1 h, PCy m Cl n is added, and the reaction continues for 1 - 3 h, and then the temperature is raised to 0 - 30 °C (such as 25 °C) and reacted for 2 - 3 h to obtain the PCy m Fc n .

[0024] According to a specific embodiment of the present invention, preferably, in the preparation method of the above PCy m Fc n Ferrocene is mixed in a mixed solvent of tetrahydrofuran and n-hexane.

[0025] According to a specific embodiment of the present invention, preferably, the preparation method of the (PCy3)(Py)2Cl2Ru=CHPh includes the following steps: under the atmosphere of a protective gas, Grubbs I catalyst is mixed in toluene, pyridine is added with stirring, after the reaction is complete, the reaction solution is poured into n-hexane at -20 to 0 °C (such as 0 °C), and a precipitate is formed to obtain the (PCy3)(Py)2Cl2Ru=CHPh.

[0026] According to a specific embodiment of the present invention, preferably, in the preparation method of the above (PCy3)(Py)2Cl2Ru=CHPh, the mass ratio of the Grubbs I catalyst to pyridine is 1:1 - 1:10, more preferably 1:3 - 1:10.

[0027] The present invention also provides an application of a ferrocene-modified ruthenium carbene olefin metathesis catalyst in catalyzing olefin metathesis reaction.

[0028] According to a specific embodiment of the present invention, preferably, the olefin metathesis reaction includes the selective synthesis of unsaturated octadecandioic acid dimethyl ester.

[0029] Ferrocene, also known as dicyclopentadienyl iron or cyclopentadienyl iron, is an aromatic organometallic compound. Its structure consists of an iron atom nested between two parallel cyclopentadienyl rings. In the solid state, the two rings are staggered in a fully staggered configuration, and rotate relative to each other around a vertical axis as the temperature rises. Ferrocene is stable, insensitive to oxygen, thermally stable (can withstand temperatures up to 470°C), and resistant to acids and alkalis. Ferrocene is the most important metallocene complex and the earliest discovered sandwich complex. Ferrocene has a wide range of applications, and its derivatives are used as anti-knock agents in gasoline. In medicine, certain ferrocene salts exhibit anticancer activity, such as the ferrocene analogue of tamoxifen, whose cytotoxicity can kill cancer cells. Ferrocene's readily sublimable nature can be exploited to deposit specific fullerenes or carbon nanotubes. In the field of catalysis, chiral ferrocenylphosphine ligands are used in reactions catalyzed by transition elements. For example, bis(diphenylphosphino)ferrocenyl (dppf) is an important ligand in organic synthesis, coordinating with metals such as ruthenium, rhodium, iridium, and palladium to carry out a variety of catalytic reactions. Ferrocene can undergo electrophilic substitution reactions such as mercurylation, alkylation, and acylation.

[0030] The present invention designs and synthesizes a series of ferrocenylphosphine ligand-modified ruthenium carbene catalysts by replacing one phosphine ligand in the Grubbs I catalyst with a ferrocenylphosphine ligand. The catalysts can provide olefin metathesis catalysts with excellent catalytic performance and can be applied to olefin metathesis reactions including the selective synthesis of unsaturated octadecandioic acid dimethyl ester.

[0031] The present invention has the following beneficial effects:

[0032] 1. The ferrocene-modified ruthenium carbene olefin metathesis catalyst of the present invention has good catalytic activity.

[0033] 2. The ferrocene-modified ruthenium carbene olefin metathesis catalyst of the present invention has good activity for the ethylene decomposition reaction of methyl oleate. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Kinetic curves of catalysts Ia, Ib, Ic and Grubbs I. DETAILED DESCRIPTION

[0035] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be understood as limiting the scope of implementation of the present invention.

[0036] Synthesis of ferrocenylphosphine ligands (A1 - A3) and (PCy3)(Py)2Cl2Ru=CHPh (A4)

[0037] Preparation Example 1: Synthesis of Ferrocene-Bis-Cyclohexylphosphine PCy2Fc (A1)

[0038] Under nitrogen protection, 0.725 g (3.91 mmol) of ferrocene was placed in a 20 mL dry ampoule, and 2 mL of anhydrous tetrahydrofuran and 2 mL of dry n-hexane were added thereto. The reaction system was cooled to 0 °C, and 1.5 mL (1.3 mol / L) of a pentane solution of tert-butyllithium was added dropwise thereto. The mixture was stirred at this temperature for 1 h, and dicyclohexylphosphine chloride (Cy2PCl) (0.40 g, 2.15 mmol) was added thereto. The reaction was continued to stir for 1 h, and then continued to stir at room temperature. The reaction progress was monitored by TLC. After stirring at room temperature for 3 h, 15 mL of an aqueous sodium hydroxide solution (1 mol / L) and 15 mL of saturated brine were added to the reaction solution, and the mixture was shaken well. The mixture was extracted with ethyl acetate (3 × 15 mL), and the organic phases were combined, dried over anhydrous magnesium sulfate. Filter paper was placed in a Buchner funnel and placed on a suction flask. The suction flask was connected to a water pump. The solution with solids was poured into the Buchner funnel to filter out the solids, and the organic phase was collected. The solution was poured into a flask and placed on a rotary evaporator. When the rotary evaporation water bath temperature was 40 °C under the water pump pressure (-0.1 MPa), all the solvents were evaporated to obtain an orange powder. The crude product was purified by silica gel column chromatography (eluent: petroleum ether: ethyl acetate = 20:1) to obtain 0.30 g of the product as an orange powder, and the yield was 41%.

[0039] 1 H NMR (400 MHz, CDCl3) δ (ppm): 1.07 - 1.35 (m, 12H, CyH), 1.67 - 1.82 (m, 10H, CyH), 4.16 - 4.31 (m, 9H, FcH); 13 C NMR (100 MHz, CDCl3): δ (ppm): 71.5, 69.2, 33.5, 30.3, 27.4, 26.5; 31 P NMR (161 MHz, CDCl3): δ (ppm): -7.34 (s).

[0040] Preparation Example 2: Synthesis of Bis-Ferrocene-Cyclohexylphosphine PCyFc2 (A2)

[0041] Under nitrogen protection, 0.725 g (3.91 mmol) of ferrocene was placed in a 20 mL dry ampoule, and 2 mL of anhydrous tetrahydrofuran and 2 mL of dry n-hexane were added thereto. The reaction system was cooled to 0 °C, and 1.5 mL (1.3 mol / L) of a pentane solution of tert-butyllithium was added dropwise thereto. The reaction was stirred at this temperature for 1 h, and cyclohexyldichlorophosphine (CyPCl2) (0.20 g, 1.05 mmol) was added thereto. Stirring was continued for 1 h, and then stirring was continued at room temperature. The reaction progress was monitored by TLC; after stirring at room temperature for 3 h, 15 mL of an aqueous sodium hydroxide solution (1 mol / L) and 15 mL of saturated brine were added to the reaction solution, and the mixture was shaken well. Extraction was performed with ethyl acetate (3×15 mL), and the organic phases were combined, dried over anhydrous magnesium sulfate. Filter paper was placed in a Buchner funnel, which was placed on a suction flask connected to a water pump. The solution with solids was poured into the Buchner funnel to filter out the solids, and the organic phase was collected. The solution was poured into a flask and placed on a rotary evaporator. At a water pump pressure of -0.1 MPa and a rotary evaporation water bath temperature of 40 °C, all the solvents were evaporated to obtain an orange powder. The crude product was purified by silica gel column chromatography (developing solvent: petroleum ether: ethyl acetate = 20:1) to obtain 0.25 g of an orange powder as the product, and the yield was 53%.

[0042] 1 1H-NMR (400 MHz, CDCl3): δ (ppm): 1.03 - 1.94 (m, 11H, CyH), 4.08 - 4.32 (m, 18H, FcH); 13 13C-NMR (100 MHz, CDCl3): δ (ppm): 72.8, 71.8, 69.4, 37.3, 31.4, 27.5, 26.3; 31 31P NMR (161 MHz, CDCl3): δ (ppm): -21.01 (s).

[0043] Preparation Example 3: Synthesis of tris-diferrocenylphosphine PFc3 (A3)

[0044] Under nitrogen protection, 0.725 g (3.91 mmol) of ferrocene was placed in a 20 mL dry ampoule, and 2 mL of anhydrous tetrahydrofuran and 2 mL of dry n-hexane were added thereto. The reaction system was cooled to 0 °C, and 1.5 mL (1.3 mol / L) of a pentane solution of tert-butyllithium was added dropwise thereto. The mixture was stirred at this temperature for 1 h, and phosphorus trichloride (0.11 g, 0.78 mmol) was added thereto. The reaction was continued to stir for 1 h, and then continued to stir at room temperature. The reaction progress was monitored by TLC; after stirring at room temperature for 3 h, 15 mL of an aqueous sodium hydroxide solution (1 mol / L) and 15 mL of saturated brine were added to the reaction solution. The mixture was shaken well, extracted with ethyl acetate (3×15 mL), and the organic phases were combined, dried over anhydrous magnesium sulfate. Filter paper was placed in a Buchner funnel and placed on a suction flask. The suction flask was connected to a water pump. The solution with solids was poured into the Buchner funnel to filter out the solids. The organic phase was collected, and the solution was poured into a flask and placed on a rotary evaporator. At a water pump pressure of -0.1 MPa and a rotary evaporation water bath temperature of 40 °C, all the solvents were evaporated to obtain an orange powder. The crude product was purified by silica gel column chromatography (eluent: petroleum ether: ethyl acetate = 20:1) to obtain 0.20 g of the product as an orange powder, and the yield was 53%.

[0045] 1 1H-NMR (400 MHz, CDCl3): δ (ppm): 4.10 - 4.19 (m, 27H, FcH); 13 13C-NMR (100 MHz, CDCl3) δ (ppm): 72.6, 69.8; 31 31P NMR (161 MHz, CDCl3): δ (ppm): -42.47 (s).

[0046] Preparation Example 4: Synthesis of ruthenium complex (tricyclohexylphosphino) dichloro (benzylidene) (bis-pyridine) ruthenium (A4), (PCy3)(Py)2Cl2Ru=CHPh

[0047] Under nitrogen protection, Grubbs I catalyst (0.50 g) was added to a 25 mL dry flask, and 5 mL of dry toluene was added to the flask. With stirring, 1.5 mL of pyridine was slowly added thereto. The color of the reaction solution changed rapidly from purple to green. The reaction solution was stirred at room temperature until the Grubbs I was completely converted (1 h). The reaction solution was poured into frozen (-20 °C) n-hexane, and a light green precipitate was precipitated. It was centrifuged on a centrifuge to precipitate solid insoluble matter. Filter paper was placed in a Buchner funnel and placed on a suction flask. The suction flask was connected to a water pump. The reaction solution with solids was poured into the Buchner funnel to filter out the solids. The solid was rinsed with n-hexane (3×20 mL) in the Buchner funnel, and then the solid was collected into a dry flask and the solvent was dried with a vacuum pump to obtain a green solid powder, obtaining 0.35 g of compound A4, and the yield was 92%.

[0048] 1 H-NMR (400 MHz, CDCl3): δ (ppm): 1.23 (br m, 9H, PCy3), 1.68 - 1.77 (br m, 15H, PCy3), 2.02 - 2.05 (br m, 6H, PCy3), 2.32 - 2.40 (q, 3H, PCy3), 7.02 - 7.08 (br s, 2H, Py), 7.16 - 7.19 (t, 2H, Ph), 7.31 (br s, 2H, Py), 7.51 - 7.55 (t, 1H, Ph), 7.68 - 7.82 (br m, 2H, Py), 7.97 - 7.99 (d, 2H, Ph), 8.40 (br s, 2H, Py), 8.88 (br s, 2H, Py), 20.04 - 20.07 (d, 1H, Ru=CH); 13 C-NMR (100 MHz, CDCl3) δ (ppm): 153.2, 150.4, 136.6, 135.0, 129.8, 129.0, 128.6, 34.8, 29.9, 27.8, 26.4; 31 P NMR (161 MHz, CDCl3): δ (ppm): 35.71 (s).

[0049] Synthesis of catalysts Ia - Ic

[0050] Preparation Example 5: Synthesis of Ruthenium Complex (Tricyclohexylphosphine)(Ferrocene-bis-cyclohexylphosphine) Dichloro(benzylidene)(pyridine)ruthenium (PCy3)(PCy2Fc)(Py)Cl2Ru=CHPh (Ia)

[0051] Under nitrogen protection, 0.23 g (0.6 mmol) of ferrocene-bis-cyclohexylphosphine (A1) and 0.34 g (0.5 mmol) of ruthenium complex (A4) were added to a 10 mL dry flask, and 5 mL of dry dichloromethane was added. The reaction was stirred at room temperature, and TLC was used to monitor until A4 was completely converted, which took about 1 h. The reaction solution was poured into a silica gel column and quickly passed through the silica gel column under pressure (-0.1 MPa), with the eluent (petroleum ether:dichloromethane = 2:1). 0.43 g of a pink solid was obtained, and the yield was 86%.

[0052] Analytical Data. Calcd (found) for: C 52 H 75 Cl2FeNP2Ru C, 62.21 (61.98); H, 7.48 (7.64); N, 1.40 (1.42). 1H-NMR(400 MHz, CDCl3): δ(ppm): 1.08 - 1.12 (m, 21H, Cy), 1.85 - 1.88 (m, 28H, Cy), 2.44 - 2.73 (m, 6H, Cy), 4.27 - 4.32 (m, 9H, FcH), 7.08 - 7.21 (m, 3H, Ph), 7.30 (m, 1H, Ph), 7.43 (m, 3H, Py), 7.86 - 7.87 (d, 1H, Ph), 8.14 - 8.15 (m, 1H, Py), 8.49 - 8.51 (m, 1H, Py), 19.82 - 19.89 (d, 1H, Ru=CH); 13 C-NMR(100 MHz, CDCl3) δ(ppm): 152.6, 152.5, 134.4, 132.3, 130.9, 130.7, 129.7, 76.2, 69.6, 33.4, 30.3, 27.4, 26.5; 31 P NMR(161 MHz, CDCl3): δ(ppm): 28.29 (s), 34.05 (s).

[0053] Preparation Example 6: Synthesis of Ruthenium Complex (tricyclohexylphosphine)(bis - ferrocenyl - cyclohexylphosphine)dichloro(benzylidene)ruthenium (PCy3)(PCyFc2)Cl2Ru=CHPh (Ib):

[0054] Under nitrogen protection, 0.29 g (0.6 mmol) of bis - ferrocenyl - cyclohexylphosphine (A2) and 0.34 g (0.5 mmol) of ruthenium complex (A4) were added to a 10 mL dry flask, 5 mL of dry dichloromethane was added, and the reaction was stirred at room temperature. TLC was used to monitor the reaction until A4 was completely converted, which took about 1 h. The reaction mixture was poured into a silica gel column and quickly passed through the silica gel column under pressure (-0.1 MPa), with the eluent (petroleum ether: dichloromethane = 2:1). A pink solid of 0.44 g was obtained, with a yield of 82%.

[0055] Analytical Data. Calcd (found) for: C 55 H 66 Cl2Fe2P2Ru C, 61.57 (61.21); H, 6.16 (6.29). 1H-NMR (400 MHz, CDCl3): δ (ppm): 1.39 - 1.45 (m, 15H, Cy), 1.66 - 1.68 (m, 11H, Cy), 1.84 - 1.94 (m, 12H, Cy), 2.60 - 2.62 (m, 6H, Cy), 4.25 - 4.32 (m, 18H, FcH), 7.32 - 7.34 (m, 2H, Ph), 7.53 - 7.55 (m, 1H, Ph), 8.42 - 8.44 (m, 2H, Ph), 19.99 (s, 1H, Ru=CH); 13 C-NMR (100 MHz, CDCl3) δ (ppm): 156.9, 131.6, 129.6, 129.2, 72.4, 71.9, 69.5, 36.1, 30.2, 29.1, 27.3; 31 P NMR (161 MHz, CDCl3): δ (ppm): 37.35 (s), 45.24 (s).

[0056] Preparation Example 7: Synthesis of Ruthenium Complex (tricyclohexylphosphine)(tri - ferrocenylphosphine)dichloro(benzylidene)(pyridine)ruthenium (PCy3)(PFc3)(Py)Cl2Ru=CHPh (Ic):

[0057] Under nitrogen protection, 0.35 g (0.6 mmol) of tri - ferrocenylphosphine (A3) and 0.34 g (0.5 mmol) of ruthenium complex (A4) were added to a 10 mL dry flask, 5 mL of dry dichloromethane was added, and the reaction was stirred at room temperature. TLC was used to monitor the reaction until A4 was completely converted, which took about 1 h. The reaction solution was poured into a silica gel column and quickly passed through the silica gel column under pressure (-0.1 MPa). The eluent was (petroleum ether: dichloromethane = 2:1). 0.46 g of a pink solid was obtained, and the yield was 76%.

[0058] Analytical Data. Calcd (found) for: C 60 H 71 C l2 Fe3NP2Ru C, 59.65 (59.03); H, 5.88 (5.96); N, 1.16 (1.21). 11H-NMR (400 MHz, CDCl3): δ (ppm): 1.32 - 1.36 (m, 19H, Cy), 1.60 - 1.61 (m, 8H, Cy), 2.55 (m, 6H, Cy), 4.00 - 4.13 (m, 27H, FcH), 7.05 - 7.06 (m, 1H, Ph, Py), 7.19 (m, 1H, Ph, Py), 7.24 - 7.27 (m, 2H, Ph, Py), 7.46 - 7.47 (m, 3H, Ph, Py), 8.37 - 8.38 (m, 2H, Ph, Py), 19.93 (s, 1H, Ru=CH); 13 13C-NMR (100 MHz, CDCl3) δ (ppm): 161.8, 157.2, 134.6, 132.3, 130.9, 130.2, 127.7, 83.9, 79.1, 38.7, 29.2, 28.9, 27.0; 31 31P NMR (161 MHz, CDCl3): δ (ppm): 45.99 (s), 51.31 (s).

[0059] Operating procedure of catalytic reaction

[0060] An appropriate amount of catalyst was added to a Schlenk tube. Under a nitrogen atmosphere, the DCM solution of the substrate was added thereto by a syringe. Then, the reaction mixture was placed at a specified temperature and time for reaction. After the reaction was completed, the reaction mixture was passed through a silica gel column and eluted with DCM. The obtained liquid mixture was rotary evaporated, concentrated, separated, and purified to obtain the product.

[0061] Catalyst activity test

[0062] (1) The activity of the catalyst was tested using diethyl 2,2-diallylmalonate as the substrate. The reaction conditions for the test were as follows: 0.5 mmol of diethyl 2,2-diallylmalonate, the catalyst dosage was 1 mol%, the reaction temperature was 30 °C, the concentration was 0.1 mol / L, and the reaction was carried out under nitrogen. After the reaction proceeded for 30 min, the reaction solution was taken out, and 0.1 mol / L of PEI was added to terminate the reaction. The reaction solution was passed through a silica gel column (eluent: CH2Cl2) to obtain a mixture of diethyl 2,2-diallylmalonate and cyclopentene-4,4'-dicarboxylate. The obtained mixture was concentrated and dried, and then 1 1H-NMR detection was performed, and the conversion rate was obtained by comparing the integral areas of the product and the raw material.

[0063] The results of the reaction conversion rates of catalysts Ia, Ib, Ic, and Grubbs I for the catalysis of diethyl 2,2-diallylmalonate under the above conditions are as Figure 1As shown, the catalytic activities of Ia and Ic are much higher than that of Grubbs I catalyst, and the activity of Ib is slightly lower than that of Grubbs I catalyst.

[0064] (2) Using N,N-diallylbenzamide as the substrate and Ia as the catalyst, 0.5 mmol of the substrate was taken, and common solvents for ring-closing metathesis such as dichloromethane, toluene, tetrahydrofuran, and acetonitrile were used as solvents, and the catalyst dosage was 1 mol%. The results showed that the yield was 98% when the solvent was dichloromethane, 84% when it was toluene, 65% when it was tetrahydrofuran, and 53% when it was acetonitrile. Therefore, dichloromethane was selected as the solvent.

[0065] The reaction temperature was screened at room temperature, 30 °C, 40 °C, and 50 °C. Using N,N-diallylbenzamide as the substrate and Ia as the catalyst. When the reaction was carried out at room temperature (25 °C), the yield was 98%, 98% at 30 °C, 98% at 40 °C, and 98% at 50 °C. Therefore, the optimal reaction temperature was room temperature (25 °C). The dosages of the catalyst, solvent, etc. were all the optimal conditions in the condition screening.

[0066] Test Example 1

[0067] 0.5 mmol of N,N-diallylbenzamide was dissolved in 0.5 mL of dichloromethane, and then 1 mol% of the catalyst (Grubbs I, Ia, Ib, Ic) was added thereto, and the reaction was carried out at 25 °C for 1 hour. After the reaction was completed, it was added to a silica gel column with a height of 10 cm (300 mesh), and a solvent of petroleum ether:ethyl acetate = 10:1 was used as the developing agent to purify the target product.

[0068] (2,5-Dihydro-1H-pyrrol-1-yl)(phenyl)methanone: Yield: 91% (Grubbs I), 98% (Ia), 97% (Ib), 98% (Ic).

[0069] 1 H NMR (400 MHz, CDCl3) δ 7.51 (dd, J = 7.2, 2.6 Hz, 2H), 7.46–7.32 (m, 3H), 5.88 (dt, J = 4.5, 2.3 Hz, 1H), 5.78–5.68 (m, 1H), 4.43 (s, 2H), 4.17 (d, J = 1.8 Hz, 2H). 13 C NMR (101 MHz, CDCl3) δ 169.77, 136.74, 129.82, 128.33, 126.72, 125.78, 125.27, 55.74, 53.35.

[0070] Test Example 2

[0071] 0.5 mmol of N,N-diallyl-4-methylbenzamide was dissolved in 0.5 mL of dichloromethane, and then 1 mol% of the catalyst (Grubbs I, Ia, Ib, Ic) was added thereto. The reaction was carried out at 25 °C for 1 hour. After the reaction was completed, it was added to a silica gel column with a height of 10 cm (300 mesh), and a solvent of petroleum ether:ethyl acetate = 10:1 was used as the developing agent to purify the target product.

[0072] (2,5-Dihydro-1H-pyrrol-1-yl)(p-tolyl)methanone: Yield: 96% (Grubbs I), 98% (Ia), 98% (Ib), 99% (Ic).

[0073] 1 H NMR (400 MHz, CDCl3) δ 7.43 (d, J = 7.7 Hz, 2H), 7.21 (d, J = 7.7 Hz, 2H), 5.90 (s, 1H), 5.75 (s, 1H), 4.45 (s, 2H), 4.22 (s, 2H), 2.38 (s, 3H). 13 C NMR (101 MHz, CDCl3) δ 170.04, 140.02, 133.94, 128.98, 126.95, 126.00, 125.26, 55.85, 53.45, 21.43.

[0074] Test Example 3

[0075] 0.5 mmol of N,N-diallyl-4-ethylbenzamide was dissolved in 0.5 mL of dichloromethane, and then 1 mol% of the catalyst (Grubbs I, Ia, Ib, Ic) was added thereto. The reaction was carried out at 25 °C for 1 hour. After the reaction was completed, it was added to a silica gel column with a height of 10 cm (300 mesh), and a solvent of petroleum ether:ethyl acetate = 10:1 was used as the developing agent to purify the target product.

[0076] (2,5-Dihydro-1H-pyrrol-1-yl)(4-ethylphenyl)methanone: Yield: 46% (Grubbs I), 67% (Ia), 52% (Ib), 74% (Ic).

[0077] 11H NMR (400 MHz, CDCl3) δ 7.46 (d, J = 7.7 Hz, 2H), 7.23 (d, J = 7.8 Hz, 2H), 5.91 (s, 1H), 5.75 (s, 1H), 4.46 (s, 2H), 4.24 (s, 2H), 2.68 (q, J = 7.6 Hz, 2H), 1.24 (t, J = 7.6 Hz, 3H). 13 13C NMR (101 MHz, CDCl3) δ 170.07, 146.29, 134.16, 127.82, 127.00, 126.01, 125.25, 55.86, 53.45, 28.78, 15.42.

[0078] Test Example 4

[0079] 0.5 mmol of N,N-diallyl-4-ethoxybenzamide was dissolved in 0.5 mL of dichloromethane, and then 1 mol% of the catalyst (Grubbs I, Ia, Ib, Ic) was added thereto. The reaction was carried out at 25 °C for 1 hour. After the reaction was completed, it was added to a silica gel column with a height of 10 cm (300 mesh), and petroleum ether:ethyl acetate = 10:1 was used as the eluent to purify the target product.

[0080] (2,5-Dihydro-1H-pyrrol-1-yl)(4-ethoxyphenyl)methanone: Yield: 89% (Grubbs I), 96% (Ia), 93% (Ib), 96% (Ic).

[0081] 1 1H NMR (400 MHz, CDCl3) δ 7.43 (s, 2H), 6.81 (s, 2H), 5.80 (s, 1H), 5.66 (s, 1H), 4.35 (s, 2H), 4.17 (s, 2H), 3.97 (s, 2H), 1.32 (s, 3H). 13 13C NMR (101 MHz, CDCl3) δ 169.61, 160.17, 128.87, 128.69, 125.91, 125.26, 113.95, 63.47, 55.89, 53.55, 14.72.

[0082] Test Example 5

[0083] 0.5 mmol of N,N-diallyl-4-fluorobenzamide was dissolved in 0.5 mL of dichloromethane, and then 1 mol% of the catalyst (Grubbs I, Ia, Ib, Ic) was added thereto. The reaction was carried out at 25 °C for 1 hour. After the reaction was completed, it was added to a 10-cm-high silica gel column (300 mesh), and a solvent of petroleum ether:ethyl acetate = 10:1 was used as the eluent to purify the target product.

[0084] (2,5-Dihydro-1H-pyrrol-1-yl)(4-fluorophenyl)methanone: Yield: 90% (Grubbs I), 96% (Ia), 93% (Ib), 97% (Ic).

[0085] 1 H NMR (400 MHz, CDCl3) δ 7.59–7.38 (m, 2H), 7.02 (t, J = 8.6 Hz, 2H), 5.83 (s, 1H), 5.68 (s, 1H), 4.37 (s, 2H), 4.14 (s, 2H). 13 C NMR (101 MHz, CDCl3) δ 168.86, 163.48 (d, JCF = 249.7 Hz), 132.86 (d, JCF = 3.5 Hz), 129.18 (d, JCF = 8.7 Hz), 126.00, 125.11, 115.53, 115.31, 55.85, 53.53. 19F NMR (376 MHz, CDCl3) δ -110.12.

[0086] Test Example 6

[0087] 0.5 mmol of N,N-diallyl-4-chlorobenzamide was dissolved in 0.5 mL of dichloromethane, and then 1 mol% of the catalyst (Grubbs I, Ia, Ib, Ic) was added thereto. The reaction was carried out at 25 °C for 1 hour. After the reaction was completed, it was added to a 10-cm-high silica gel column (300 mesh), and a solvent of petroleum ether:ethyl acetate = 10:1 was used as the eluent to purify the target product.

[0088] (4-Chlorophenyl)(2,5-dihydro-1H-pyrrol-1-yl)methanone: Yield: 88% (Grubbs I), 97% (Ia), 93% (Ib), 98% (Ic).

[0089] 11H NMR (400 MHz, CDCl3) δ 7.49 (d, J = 8.2 Hz, 2H), 7.39 (d, J = 8.1 Hz, 2H), 5.91 (s, 1H), 5.76 (s, 1H), 4.44 (s, 2H), 4.20 (s, 2H). 13 13C NMR (101 MHz, CDCl3) δ 168.76, 135.92, 135.12, 128.68, 128.41, 126.01, 125.10, 55.79, 53.53.

[0090] Test Example 7

[0091] 0.5 mmol of N,N-diallyl-4-cyanobenzamide was dissolved in 0.5 mL of dichloromethane, and then 1 mol% of the catalyst (Grubbs I, Ia, Ib, Ic) was added thereto. The reaction was carried out at 25 °C for 1 hour. After the reaction was completed, it was added to a 10-cm-high silica gel column (300 mesh), and petroleum ether:ethyl acetate = 10:1 was used as the eluent to purify the target product.

[0092] 4-(2,5-Dihydro-1H-pyrrole-1-carbonyl)benzonitrile: Yield: 54% (Grubbs I), 75% (Ia), 62% (Ib), 73% (Ic).

[0093] 1 1H NMR (400 MHz, CDCl3) δ 7.75 (d, J = 7.8 Hz, 2H), 7.66 (d, J = 7.9 Hz, 2H), 5.94 (s, 1H), 5.79 (s, 1H), 4.45 (s, 2H), 4.19 (s, 2H). 13 13C NMR (101 MHz, CDCl3) δ 167.73, 140.93, 132.39, 127.55, 125.88, 125.01, 118.14, 113.51, 55.59, 53.52.

[0094] Test Example 8

[0095] 0.5 mmol of N,N-diallyl-4-nitrobenzamide was dissolved in 0.5 mL of dichloromethane, and then 1 mol% of the catalyst (Grubbs I, Ia, Ib, Ic) was added thereto. The reaction was carried out at 25 °C for 1 hour. After the reaction was completed, it was added to a 10-cm-high silica gel column (300 mesh), and petroleum ether:ethyl acetate = 10:1 was used as the eluent to purify the target product.

[0096] (2,5-dihydro-1H-pyrrol-1-yl)(4-nitrophenyl)methanone: Yield: 86% (Grubbs I), 95% (Ia), 92% (Ib), 96% (Ic).

[0097] 1 H NMR (400 MHz, CDCl3) δ 8.30 (d, J = 8.5 Hz, 2H), 7.71 (d, J = 8.6 Hz, 2H), 5.99–5.92 (m, 1H), 5.83–5.71 (m, 1H), 4.48 (s, 2H), 4.18 (s, 2H). 13 C NMR (101 MHz, CDCl3) δ 167.59, 148.50, 142.75, 127.95, 126.09, 124.92, 123.89, 55.65, 53.60.

[0098] Test Example 9

[0099] 0.5 mmol of N,N-diallyl-2-methylbenzamide was dissolved in 0.5 mL of dichloromethane, and then 1 mol% of the catalyst (Grubbs I, Ia, Ib, Ic) was added thereto. The reaction was carried out at 25 °C for 1 hour. After the reaction was completed, it was added to a silica gel column with a height of 10 cm (300 mesh), and petroleum ether:ethyl acetate = 10:1 was used as the eluent to purify the target product.

[0100] (2,5-dihydro-1H-pyrrol-1-yl)(o-tolyl)methanone: Yield: 89% (Grubbs I), 94% (Ia), 93% (Ib), 95% (Ic).

[0101] 1 H NMR (400 MHz, CDCl3) δ 7.30–7.25 (m, 1H), 7.22 (t, J = 3.8 Hz, 3H), 5.91 (dt, J = 6.6, 2.2 Hz, 1H), 5.73 (dt, J = 6.5, 2.0 Hz, 1H), 4.45 (s, 2H), 3.93 (s, 2H), 2.33 (s, 3H). 13 C NMR (101 MHz, CDCl3) δ 169.95, 137.31, 133.70, 130.54, 128.94, 126.01, 125.95, 125.40, 125.30, 54.94, 52.58, 18.98.

[0102] Test Example 10

[0103] 0.5 mmol of N,N-diallyl-2,4,6-trimethylbenzamide was dissolved in 0.5 mL of dichloromethane, and then 1 mol% of the catalyst (Grubbs I, Ia, Ib, Ic) was added thereto. The reaction was carried out at 25 °C for 1 hour. After the reaction was completed, it was added to a silica gel column with a height of 10 cm (300 mesh), and a solvent of petroleum ether:ethyl acetate = 10:1 was used as the eluent to purify the target product.

[0104] (2,5-Dihydro-1H-pyrrol-1-yl)(mesityl)methanone: Yield: 87% (Grubbs I), 91% (Ia), 89% (Ib), 94% (Ic).

[0105] 1 H NMR (400 MHz, CDCl3) δ 6.85 (s, 2H), 5.96–5.84 (m, 1H), 5.78–5.67 (m, 1H), 4.43 (s, 2H), 3.80 (s, 2H), 2.26 (s, 3H), 2.22 (s, 6H). 13 C NMR (101 MHz, CDCl3) δ 169.96, 137.98, 134.55, 132.83, 128.27, 125.89, 125.35, 54.11, 52.16, 21.07, 18.83.

[0106] Test Example 11

[0107] 0.5 mmol of N,N-diallyl-1-naphthamide was dissolved in 0.5 mL of dichloromethane, and then 1 mol% of the catalyst (Grubbs I, Ia, Ib, Ic) was added thereto. The reaction was carried out at 25 °C for 1 hour. After the reaction was completed, it was added to a silica gel column with a height of 10 cm (300 mesh), and a solvent of petroleum ether:ethyl acetate = 10:1 was used as the eluent to purify the target product.

[0108] (2,5-Dihydro-1H-pyrrol-1-yl)(naphthalen-1-yl)methanone: Yield: 88% (Grubbs I), 94% (Ia), 90% (Ib), 93% (Ic).

[0109] 11H NMR (400 MHz, CDCl3) δ 7.86 (d, J = 5.9 Hz, 3H), 7.49 (dd, J = 11.7, 4.5 Hz, 4H), 5.90 (s, 1H), 5.65 (s, 1H), 4.57 (s, 2H), 3.90 (s, 2H). 13 13C NMR (101 MHz, CDCl3) δ 169.34, 135.27, 133.59, 129.30, 128.98, 128.47, 127.10, 126.40, 125.77, 125.43, 125.29, 124.82, 123.72, 54.98, 52.93.

[0110] Test Example 12

[0111] 0.5 mmol of N,N-diallyl-2-naphthamide was dissolved in 0.5 mL of dichloromethane, and then 1 mol% of the catalyst (Grubbs I, Ia, Ib, Ic) was added thereto. The reaction was carried out at 25 °C for 1 hour. After the reaction was completed, it was added to a silica gel column with a height of 10 cm (300 mesh), and petroleum ether:ethyl acetate = 10:1 was used as the developing solvent to purify the target product.

[0112] (2,5-Dihydro-1H-pyrrol-1-yl)(naphthalen-2-yl)methanone: Yield: 89% (Grubbs I), 94% (Ia), 87% (Ib), 97% (Ic).

[0113] 1 1H NMR (400 MHz, CDCl3) δ 8.00 (s, 1H), 7.84 (t, J = 9.1 Hz, 3H), 7.60 (d, J = 9.2 Hz, 1H), 7.54–7.46 (m, 2H), 5.88 (s, 1H), 5.71 (s, 1H), 4.49 (s, 2H), 4.22 (s, 2H). 13 13C NMR (101 MHz, CDCl3) δ 169.90, 134.12, 133.78, 132.62, 128.49, 128.29, 127.79, 127.14, 126.71, 126.65, 125.93, 125.29, 124.14, 55.91, 53.54.

[0114] Test Example 13: Investigation of the ethylene cleavage reaction activity of methyl oleate

[0115] This reaction has relatively high requirements for the purity of methyl oleate, and commercially available methyl oleate needs to be purified:

[0116] First, there may be impurities such as residual acid or base in commercially available methyl oleate. This has a very significant impact on the catalytic efficiency of the catalyst, so it is necessary to remove the influence of factors such as acid and base. The specific method is as follows: Neutral alumina with a thickness of 7 - 12 cm is filled in the bottom layer of the column, and basic alumina with a thickness of 12 cm is filled in the upper layer. 10 mL of methyl oleate is dissolved in 50 - 100 mL of petroleum ether, added to the column, and the column is directly flushed with petroleum ether until the methyl oleate is completely flushed out. After removing the petroleum ether, it is pumped under a vacuum for 3 - 8 hours to remove the residual petroleum ether.

[0117] Secondly, gases such as oxygen in methyl oleate will also affect the catalyst. Therefore, it is necessary to degas methyl oleate. The specific method is as follows: The methyl oleate from which acid and base impurities have been removed is placed in liquid nitrogen until the liquid turns into a solid state, and then placed under a vacuum pump until it reaches room temperature. At this time, the methyl oleate changes from a solid state to a liquid state. This process is repeated 3 - 5 times to remove dissolved gases such as oxygen in the methyl oleate. After degassing, nitrogen is filled, and it is stored in a glove box for later use.

[0118] This test example compared the ethylene cleavage reaction activities of Grubbs I, Ia - Ic for methyl oleate:

[0119] Method 1 for the ethylene cleavage of methyl oleate: A magnetic stir bar, 50 μL of n - dodecane (chromatographically pure, internal standard), and the methyl oleate (1 mL) processed according to the above method are added to a 10 - mL high - pressure reactor. Subsequently, 10 μL of a toluene solution of catalyst Ia, Ib, Ic or Grubbs I (1 mg of catalyst is dissolved in 1 mL of toluene, and the catalyst concentration is 100 ppm at this time) is added. The reactor is evacuated with a vacuum pump for 1 minute, and ethylene gas is introduced to make the reactor slightly positively pressured (0.01 MPa). This process is repeated 3 times. Then, it is evacuated with a vacuum pump for another minute, and the ethylene in the reactor is increased to a certain pressure (150 psi). The reactor is placed in a reaction module maintained at a constant temperature (20 °C, 30 °C, 40 °C, 50 °C), stirred and reacted, and the gas chromatography is sampled and detected every half hour. The yield will not continue to increase after 6 hours of reaction, and the selectivity for the products octadec - 9 - ene and dimethyl octadec - 9 - enedioate is greater than 99%.

[0120] At 20 °C, the conversion rate of methyl oleate catalyzed by catalyst Ia reached 26.0%, and the TON value was 4059; at 30 °C, the conversion rate of methyl oleate catalyzed by catalyst Ia reached 36.8%, and the TON value was 5746; at 40 °C, the conversion rate of methyl oleate catalyzed by catalyst Ia reached 41.2%, and the TON value was 6431; at 50 °C, the conversion rate of methyl oleate catalyzed by catalyst Ia reached 40.4%, and the TON value was 6308. At 20 °C, the conversion rate of methyl oleate catalyzed by catalyst Ib reached 22.9%, and the TON value was 3545; at 30 °C, the conversion rate of methyl oleate catalyzed by catalyst Ib reached 31.1%, and the TON value was 4826; at 40 °C, the conversion rate of methyl oleate catalyzed by catalyst Ib reached 37.7%, and the TON value was 5844; at 50 °C, the conversion rate of methyl oleate catalyzed by catalyst Ib reached 36.1%, and the TON value was 5598. At 20 °C, the conversion rate of methyl oleate catalyzed by catalyst Ic reached 27.7%, and the TON value was 4324; at 30 °C, the conversion rate of methyl oleate catalyzed by catalyst Ic reached 36.8%, and the TON value was 5748; at 40 °C, the conversion rate of methyl oleate catalyzed by catalyst Ic reached 44.6%, and the TON value was 6961; at 50 °C, the conversion rate of methyl oleate catalyzed by catalyst Ic reached 42.8%, and the TON value was 6680. At 20 °C, the conversion rate of methyl oleate catalyzed by Grubbs I reached 27.3%, and the TON value was 4339; at 30 °C, the conversion rate of methyl oleate catalyzed by Grubbs I reached 32.7%, and the TON value was 5182; at 40 °C, the conversion rate of methyl oleate catalyzed by Grubbs I reached 37.8%, and the TON value was 5990; at 50 °C, the conversion rate of methyl oleate catalyzed by Grubbs I reached 33.5%, and the TON value was 5305. At different reaction temperatures, the conversion rates and TON values of catalysts Ia and Ic are higher than those of Grubbs I, while the conversion rate and TON value of Ib are lower than those of Grubbs I.

[0121] Methyl oleate ethyleneolysis method two: Add a magnetic stir bar, 50 μL of n-dodecane (chromatographically pure, internal standard), and methyl oleate (1 mL) treated by the above method into a 10 mL high-pressure reactor. Subsequently, add 10 μL of a toluene solution of catalyst Ia, Ib, Ic, or Grubbs I (1 mg of catalyst is dissolved in 1 mL of toluene, and the catalyst concentration is 100 ppm at this time). Evacuate the reactor with a vacuum pump for 1 minute, and introduce ethylene gas to make the reactor slightly positive pressure (0.01 MPa). This process is repeated 3 times. Then evacuate the reactor with a vacuum pump for another minute, and increase the ethylene pressure in the reactor to a certain pressure (50 psi, 100 psi, 150 psi, 200 psi). Place the reactor in a reaction module maintained at a certain temperature (40 °C), stir and react, and take samples every half hour to detect gas chromatography. The yield will not continue to increase after 6 hours of reaction, and the selectivity for the products octadec-9-ene and dimethyl octadec-9-enedioate is greater than 99%.

[0122] When the ethylene pressure is 50 psi, the conversion rate of methyl oleate catalyzed by catalyst Ia reaches 26.4%, and the TON value is 4120; when the ethylene pressure is 100 psi, the conversion rate of methyl oleate catalyzed by catalyst Ia reaches 38.2%, and the TON value is 5963; when the ethylene pressure is 150 psi, the conversion rate of methyl oleate catalyzed by catalyst Ia reaches 41.2%, and the TON value is 6431; when the ethylene pressure is 200 psi, the conversion rate of methyl oleate catalyzed by catalyst Ia reaches 39.8%, and the TON value is 6212. When the ethylene pressure is 50 psi, the conversion rate of methyl oleate catalyzed by catalyst Ib reaches 22.1%, and the TON value is 3426; when the ethylene pressure is 100 psi, the conversion rate of methyl oleate catalyzed by catalyst Ib reaches 34.6%, and the TON value is 5363; when the ethylene pressure is 150 psi, the conversion rate of methyl oleate catalyzed by catalyst Ib reaches 37.7%, and the TON value is 5844; when the ethylene pressure is 200 psi, the conversion rate of methyl oleate catalyzed by catalyst Ib reaches 36.4%, and the TON value is 5642. When the ethylene pressure is 50 psi, the conversion rate of methyl oleate catalyzed by catalyst Ic reaches 24.6%, and the TON value is 3839; when the ethylene pressure is 100 psi, the conversion rate of methyl oleate catalyzed by catalyst Ic reaches 39.3%, and the TON value is 6133; when the ethylene pressure is 150 psi, the conversion rate of methyl oleate catalyzed by catalyst Ic reaches 44.6%, and the TON value is 6961; when the ethylene pressure is 200 psi, the conversion rate of methyl oleate catalyzed by catalyst Ic reaches 41.8%, and the TON value is 6523. When the ethylene pressure is 50 psi, the conversion rate of methyl oleate catalyzed by Grubbs I reaches 21.7%, and the TON value is 3439; when the ethylene pressure is 100 psi, the conversion rate of methyl oleate catalyzed by Grubbs I reaches 32.5%, and the TON value is 5150; when the ethylene pressure is 150 psi, the conversion rate of methyl oleate catalyzed by Grubbs I reaches 37.8%, and the TON value is 5990; when the ethylene pressure is 200 psi, the conversion rate of methyl oleate catalyzed by Grubbs I reaches 35.1%, and the TON value is 5562. At different ethylene pressures, the conversion rates and TON values of catalysts Ia and Ic are higher than those of Grubbs I. Under the optimal reaction conditions, the conversion rate and TON value of Ib are slightly lower than those of Grubbs I.

[0123] After condition screening, the optimal reaction conditions are: temperature: 40 °C; pressure: 150 psi; reaction time: 6 h. Under these conditions, the ethyleneolysis reaction of methyl oleate was carried out using Grubbs I, Ia - Ic, and the results are shown in Table 1.

[0124] Table 1

[0125] Conversion rate % Selectivity % TON Grubbs I catalyst 37.8 99％ 5990 Ia 41.2 99％ 6431 Ib 37.7 99％ 5844 Ic 44.6 99％ 6961

[0126] In Table 1:

[0127] Conversion rate % = 100 - [(final 1 molar amount) × 100 / (initial 1 molar amount)];

[0128] Selectivity % = (molar amount of products 4 + 5) × 100 / (molar amount of products 2 + 3 + 4 + 5);

[0129] Yield % = (total molar number of products 4 + 5) × 100 / (initial 1 molar number);

[0130] TON = Yield × [(initial 1 molar number) / (catalyst molar number)] / 100;

[0131] The reaction process is as follows:

[0132]

[0133] Under the same experimental conditions, the turnover number of the Grubbs I catalyst is 5990, while those of the Ia, Ib, and Ic catalysts are 6431, 5884, and 6961 respectively. It can be seen that the activities of the Ia and Ic catalysts for the ethenolysis reaction of methyl oleate are higher than that of the Grubbs I catalyst.

Claims

1. A ferrocene-modified ruthenium carbene olefin metathesis catalyst, which has the structure shown in Formula I: In Formula I, Fc is a ferrocene structure, m is 0 - 2, n is 1 - 3, and m + n = 3; X is a solvent ligand, and a is 0 or 1; Preferably, n is 1 or 3.

2. The ferrocene-modified ruthenium carbene olefin metathesis catalyst according to claim 1, wherein, X is selected from pyridine.

3. A method for preparing the ferrocene-modified ruthenium carbene olefin metathesis catalyst according to claim 1 or 2, which comprises the following steps: Under a protective gas atmosphere, PCy m Fc n is mixed with (PCy3)(Py)2Cl2Ru=CHPh in a solvent for reaction to obtain the ferrocene-modified ruthenium carbene olefin metathesis catalyst.

4. The preparation method according to claim 3, wherein, The reaction time is 0.5 - 5 h, and the reaction temperature is 0 - 50 °C.

5. The preparation method according to claim 3, wherein, The solvent includes dichloromethane.

6. The preparation method according to claim 3, wherein, The PCy m Fc n has a molar ratio with (PCy3)(Py)2Cl2Ru=CHPh of 1:1 - 5:

1.

7. The preparation method according to claim 3, wherein, The PCy m Fc n The preparation method thereof comprises the following steps: Under a protective gas atmosphere, ferrocene is mixed in a solvent. After cooling to 0 °C, tert-butyllithium is added dropwise, and the reaction is carried out for 0.5 - 1 h. Then PCy m Cl n is added, and the reaction is continued for 1 - 3 h. Subsequently, the temperature is raised to 0 - 30 °C and the reaction is carried out for 2 - 3 h to obtain the PCy m Fc n .

8. The preparation method according to claim 7, wherein, The described PCy m Fc n In the preparation method thereof, ferrocene is mixed in a mixed solvent of tetrahydrofuran and n-hexane.

9. Use of the ferrocene-modified ruthenium carbene olefin metathesis catalyst according to claim 1 or 2 in the catalytic olefin metathesis reaction.

10. The application according to claim 9, wherein, The olefin metathesis reaction includes the selective synthesis of dimethyl unsaturated octadecanedioate.

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