A polymer-coated mesoporous silica supported ruthenium catalyst, its preparation method and use

Abstract

The application discloses a polymer-coated mesoporous silica supported ruthenium catalyst and a preparation method and application thereof. The catalyst has a polymer-coated mesoporous silica inner core, wherein the surface of the silica inner core is grafted with triethoxysilane having an alkenyl group; the alkenyl group of the triethoxysilane serves as an active site; the polymer is formed by polymerization of a polymer monomer through the alkenyl group; and the catalyst is formed by further coordination of metal Ru. The particle size of the catalyst is between 400 nm and 600 nm. The supported ruthenium catalyst provided by the application can catalyze hydrogen transfer reduction of carbonyl compounds at a high yield (up to 99%) and high enantiomeric selectivity (up to 99%), can be recycled for 8 times through simple recovery, and is easy to be industrialized, and can reduce catalyst cost and pollution.

Description

Technical Field

[0001] This invention belongs to the field of catalysts and relates to a method for preparing a supported hydrogen transfer catalyst. Specifically, it relates to a method for preparing a polymer-coated mesoporous silica supported ruthenium catalyst and its application in carbonyl asymmetric hydrogen transfer reduction. Background Technology

[0002] Asymmetric hydrogen transfer (ATH) is a unique asymmetric reduction reaction, distinct from traditional asymmetric hydrogenation. It avoids the use of high-pressure hydrogen, making it safer. ATH is compatible with various solvent systems while using both expensive and inexpensive metal catalysts, making it widely applicable in the field of asymmetric reduction. The Noyori-ikariya catalyst, as the most widely used and mature ATH catalyst, is typically composed of noble metals rhodium / ruthenium and diamine ligands. It is simple and readily available, and can yield chiral alcohols in high yields with high enantioselectivity (J. Am. Chem. Soc., 1996, 118, 4916-4917).

[0003] However, the use of precious metals keeps the cost of catalysts high. To further expand their industrial applications, a strategy of heterogeneousizing homogeneous catalysts has been proposed, which involves connecting different supports to the catalyst to achieve catalyst immobilization. Many different support forms have been developed to date.

[0004] For example, in 2008, Li's research group introduced a Ru-PNNP catalyst on a mesoporous silica support SBA-15 via silane coupling. The catalyst could still be completely converted at S / C = 500 with ee > 99% and recovered 8 times. However, the 3-diphenylphosphinetriethoxysilane used was expensive and difficult to prepare (Chem. Commun., 2008, 347-349).

[0005]

[0006] In 2008, Itsuno's group reported a self-supporting strategy, modifying the diamine ligand terminus with vinylation to serve as a polymerization site, and constructing a polymer-supported hydrogen transfer catalyst. It showed better catalytic activity than the monomer on multiple substrates, achieving complete conversion at S / C = 100 and obtaining an ee value of up to 98%. However, its recycling capability was not reported, making it difficult to use as an alternative for industrial production, and further modification is needed (Adv. Synth. Catal. 2008, 350, 2295–2304).

[0007] Summary of the Invention

[0008] To address the problems existing in the prior art, the purpose of this invention is to provide a loading strategy that combines the advantages of the two loading forms mentioned above, namely, a method for preparing a polymer-coated mesoporous silica-supported ruthenium catalyst, which achieves efficient asymmetric reduction of carbonyl compounds, helps reduce catalyst costs, and is suitable for industrial production.

[0009] A polymer-coated mesoporous silica-supported ruthenium catalyst has a polymer-encapsulated mesoporous silica core, the structure of which is shown below:

[0010]

[0011] The present invention involves grafting a triethoxysilane with an alkenyl group onto the surface of a silica core. Using the vinyl groups of the triethoxysilane as active sites, the polymer is formed through polymerization with a polymer monomer. Further coordination loading of metallic Ru forms the catalyst, thus creating a catalyst with the structure shown in general formula I; in general formula I, R... 1 Selected from one of the following: hydrogen, C1-C6 straight-chain or branched alkyl, C1-C6 alkoxy. R 2 Selected from p-methylisopropylphenyl and mesitylene; the n 1 n 2 It is a positive integer.

[0012] The method for preparing the polymer-coated mesoporous silica-supported ruthenium catalyst as shown in Formula (I) includes the following steps:

[0013] 1) Tetraethyl orthosilicate (TEOS) (material 1') and hexadecyltrimethylammonium bromide (CTAB), ammonia, ethanol and deionized water were mixed to prepare mesoporous silica as a loading material by silicon source copolymerization, and mesoporous silica 2' was obtained by filtration, washing and drying.

[0014] 2) Mesoporous silica 2' and vinyltriethoxysilane react to obtain modified mesoporous silica 3' as a loading material;

[0015] 3) Sodium 4-vinylbenzenesulfonate and thionyl chloride were reacted to give intermediate 2. Intermediate 2 and (S,S)-disubstituted phenylethylenediamine underwent a nucleophilic reaction to give organic ligand 3.

[0016] 4) Organic ligand 3, modified mesoporous silica 3', and divinylbenzene (DVB) were copolymerized under the condition of azobisisobutyronitrile (AIBN) as an initiator to obtain the support L for the ligand;

[0017] 5) The support L of the supported ligand coordinates with the ruthenium salt to obtain the supported ruthenium catalyst as shown in Formula I. The reaction formula is as follows:

[0018]

[0019] In the structural formula of organic ligand 3, Ar represents a substituted phenyl group, and the substituents on the benzene ring of the (S,S)-disubstituted phenylethylenediamine and the substituted phenyl group in organic ligand 3 are all the same as R in the structure of general formula I. 1 same.

[0020] The specific process in step 1) is as follows: CTAB is added to an ethanol-deionized water mixed solvent at room temperature, with a volume ratio of ethanol to deionized water of 0.8-1.5:1. The concentration of TEOS in the ethanol-deionized water mixed solvent is 0.02-0.05 mmol / mL. Ammonia water is added to adjust the pH of the mixed system to 9-10. The mixture is stirred until clear, and TEOS is slowly added dropwise, with a molar ratio of TEOS to CTAB of 1:0.25-0.35. The reaction temperature is 25-40℃, and the reaction time is 3-12 h. After the reaction in step 1) is completed, the mixture is filtered, and then Soxhlet extracted in a 0.5-2% hydrochloric acid-ethanol solution at 90-100℃ for 40-50 h. The mixture is then washed with deionized water and ethanol, and dried to obtain spherical mesoporous silica.

[0021] Furthermore, the organic ligand 3 is specifically any one of the following:

[0022]

[0023] Further, in step 4), the mass ratio of modified mesoporous silica material 3' to organic ligand 3 is 1:0.3-0.8, preferably 1:0.4-0.5; the molar ratio of DVB to organic ligand 3 is 3-20:1, preferably 5-15:1; the mass of AIBN is 10-30% of the mass of organic ligand 3; the reaction is carried out in tetrahydrofuran at a temperature of 60-100℃ for 8-48 h; after the reaction is completed, deionized water is added to precipitate the solid, which is then filtered, washed with ethanol, and dried to obtain support L.

[0024] Further, in step 5), the mass ratio of ruthenium metal salt to support L is 1:6-10, the reaction is carried out in methanol solution, the reaction temperature is 25-50℃, and the reaction time is 0.5-2h. The ruthenium metal salt is [Ru(mesitylene)Cl]2 or [Ru(p-cymene)Cl]2.

[0025] Furthermore, the present invention also provides the application of a polymer-coated mesoporous silica-supported ruthenium catalyst in an asymmetric hydrogen transfer reduction reaction. The application method is as follows: a carbonyl compound and a supported ruthenium catalyst are dispersed in water, a hydrogen source is added, and the reaction is carried out under an inert gas atmosphere at a reaction temperature of 25-50°C. After reaction and purification, a highly enantioselective chiral hydroxyl compound is prepared, and the supported ruthenium catalyst is recovered by centrifugation.

[0026] Furthermore, the hydrogen source is one of formic acid / triethylamine, sodium formate, isopropanol, and methanol in a volume ratio of 1-2.5:1, and the molar ratio of the hydrogen source to the carbonyl compound is 2.2-6:1.

[0027] Furthermore, the formic acid / triethylamine with a volume ratio of 1-2.5:1 is preferably a formic acid / triethylamine (5 / 2, v / v) azeotrope, a formic acid / triethylamine (2 / 1, v / v) azeotrope, or a formic acid / triethylamine (1 / 1, v / v) azeotrope.

[0028] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0029] The supported ruthenium catalyst provided by this invention can catalyze the hydrogen transfer reduction of carbonyl compounds with high yield (up to 99%) and high enantioselectivity (up to 99%), and can achieve 8 catalyst cycles through simple recycling, reducing catalyst cost, reducing pollution, and facilitating industrialization. Attached Figure Description

[0030] Figure 1 This is the IR-ATR spectrum of the supported ruthenium catalyst ML1 prepared in Example 1 of this invention;

[0031] Figure 2 This is a high-resolution scanning electron microscope image of the supported ruthenium catalyst ML1 prepared in Example 1 of this invention;

[0032] Figure 3a This is one of the transmission electron microscope images of the supported ruthenium catalyst ML1 prepared in Example 1 of this invention;

[0033] Figure 3b This is the second transmission electron microscope image of the supported ruthenium catalyst ML1 prepared in Example 1 of this invention;

[0034] Figure 4a This is the EDS energy dispersive spectroscopy (EDS) spectrum of the supported ruthenium catalyst ML1 prepared in Example 1 of this invention;

[0035] Figure 4b This is the EDS spectrum of the supported ruthenium catalyst ML1 prepared in Example 1 of this invention. Detailed Implementation

[0036] The present invention will be further described in detail below through specific embodiments, but the present invention is not limited to the embodiments.

[0037] Example 1: Preparation of polymer-coated mesoporous silica-supported ruthenium catalyst ML1

[0038] (1) Preparation of vinyl-modified mesoporous silica (3')

[0039] At room temperature, hexadecyltrimethylammonium bromide (1 g) was added to a mixture of deionized water (37 mL) and ethanol (38 mL). Ammonia (15 mL, 25% by mass) was added to adjust the pH to 9-10. The mixture was stirred for 10 min until the system was clear. Tetraethyl orthosilicate (2.09 mL) was slowly added dropwise. After the addition was complete, the mixture was reacted at room temperature for 3 h. The resulting spherical silica precursor was obtained by filtration. The precursor was extracted with a 1% hydrochloric acid-ethanol solution at 100 °C for 48 h using a Soxhlet extractor. The precursor was then washed with deionized water and ethanol and dried under vacuum at 40 °C to obtain spherical mesoporous silica (1.9 g, yield 97.4%).

[0040] Spherical mesoporous silica (1 g) and vinyltriethoxysilane (500 mg) were dispersed in toluene (3 mL) and reacted at 70 °C for 12 h under an argon atmosphere. 4.5 mL to 10.5 mL of deionized water was added to the solvent system to precipitate the solid. After filtration, the solid was washed with 5 mL to 10 mL of ethanol and dried under vacuum at 40 °C to obtain a white solid powder, which is surface vinyl-modified spherical mesoporous silica (material 3') (1.17 g, mass yield 78%).

[0041] (2) Preparation of vinyl-modified diamine ligands (3)

[0042] Using sodium p-vinylbenzoate (compound 1) (5 mmol) as the starting material, dissolved in 5 mL of DMF, thionyl chloride (20 mmol) was slowly added dropwise at 0 °C, completing the addition within 15 min. The reaction was then allowed to proceed at room temperature, and the system gradually changed from yellow-green to white. TLC was performed using a PE:EA ratio of 5:1 (v / v). After the reaction was complete, the mixture was concentrated under reduced pressure to remove the remaining thionyl chloride and DMF. The resulting yellow-white solid was dissolved in dichloromethane and water, extracted three times with 10 mL of dichloromethane, and the combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to obtain 730 mg of p-vinylbenzenesulfonyl chloride (compound 2), with a yield of 83.0%.

[0043] Compound 2 was dissolved in 15 mL of DCM and added to a constant-pressure dropping funnel for later use. (S,S)-diphenylethylenediamine (3 mmol) and triethylamine (9 mmol) were dissolved in 5 mL of DCM under argon protection. The mixture was transferred to -8 °C for cooling, and the DCM solution of compound 2 was slowly added dropwise. The system gradually turned pale yellow. After the addition was complete, the mixture was transferred to room temperature and allowed to react overnight. The reaction was monitored by TLC with PE:EA:Et3N = 2:1:1%. After the reaction was complete, a small amount of water was added to quench the reaction. The mixture was extracted with a DCM-water system, and extracted three times with 10 mL of DCM. The organic phases were combined, washed twice with saturated brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure to obtain a pale yellow crude powder. The crude powder was then purified by column chromatography with PE:EA:Et3N = 2:1:1% to obtain the target product, vinyl-modified diamine ligand 3 (i.e., L1 ligand), with a yield of 44.1%.

[0044] (3) Preparation of polymer-coated mesoporous silica-supported ruthenium catalyst ML1

[0045] Vinyl-modified spherical mesoporous silica (3') (150 mg), vinyl-modified diamine ligand (3)L1 (75 mg, 0.2 mmol), divinylbenzene (DVB) (130 mg, 1 mmol), and azobisisobutyronitrile (16 mg, 0.1 mmol) were dispersed in 1.5 mL of tetrahydrofuran. The mixture was heated under an argon atmosphere for 24 h. 4.5 mL to 10.5 mL of deionized water was added to precipitate the solid. After filtration, the solid was washed with 5 mL to 10 mL of ethanol and dried under vacuum at 40 °C to obtain a slightly yellow powder, which was a spherical composite support (246.7 mg, yield 69.5%).

[0046] A spherical composite support (25 mg) and ruthenium metal salt [Ru(mesitylene)Cl]2 (3 mg) were dispersed in a methanol (2 mL) solution and heated to 50 °C for 1 h. After filtration, the mixture was washed with 3 mL of deionized water and 3 mL of ethanol to obtain a pale yellow powder, which was the supported ruthenium catalyst ML1 (27.5 mg, mass yield 98.2%).

[0047] The prepared supported ruthenium catalyst ML1 was characterized (see attached figure description);

[0048] Figure 1 This is the IR-ATR spectrum of the supported ruthenium catalyst ML1 prepared in Example 1 of this invention. Figure 1 Displayed at 1095cm -1 The peak at 798 cm⁻¹ is an antisymmetric stretching vibration peak of Si-O-Si. -1 466cm -1 The vibration at 3450 cm⁻¹ exhibits symmetric stretching vibration of the Si-O bond. -1The broad peak at 1638 cm⁻¹ is the antisymmetric stretching vibration peak of structural water -OH. -1 The peak at 955 cm⁻¹ is the HOH bending vibration peak. -1 The peak at that location belongs to the bending vibration absorption peak of Si-OH, which is a characteristic peak of silicon dioxide and is consistent with the characteristic peak of silicon dioxide.

[0049] Figure 2 This is a high-resolution scanning electron microscope (SEM) image of the supported ruthenium catalyst ML1 prepared in Example 1 of this invention. Figure 2 The supported catalyst exhibits a uniform and stable spherical structure with a particle size of approximately 400 nm to 600 nm.

[0050] Figure 3a and Figure 3b This is a transmission electron microscope (TEM) image of the supported ruthenium catalyst ML1 prepared in Example 1 of the present invention, showing that the supported catalyst has a bilayer structure of a regular inner layer of silica and an irregular outer layer of polymer.

[0051] Figure 4a and Figure 4b This is the EDS spectrum of the supported ruthenium catalyst ML1 prepared in Example 1 of the present invention. According to the EDS spectrum, Ru metal (blue) and polymer are distributed in the same position, indicating that Ru is basically coordinated with the ligand fragments in the polymer.

[0052] The supported ruthenium catalyst prepared in Example 1 appears as an orange-yellow powder.

[0053] Example 2: Preparation of ruthenium-supported catalyst ML1 with different polymer ratios

[0054] The polymer-coated mesoporous silica-supported ruthenium catalyst ML1 was prepared using a method similar to that in Example 1, except that: the amount of vinyl-modified mesoporous silica (3') was kept at 150 mg, the amount of DVB was changed, and the molar ratio of ligand L1 (n1) and DVB (n2) in step (3) was adjusted, as shown in the table below:

[0055] Table 1. Ruthenium supported catalysts ML1 to ML1-4 with different polymer ratios.

[0056]

[0057]

[0058] Table 1 shows the specific compositions of the polymer catalysts to explore the optimal catalyst composition ratios.

[0059] Example 3: Comparison of the asymmetric hydrogen transfer catalytic reduction performance of ML1-X supported ruthenium catalysts for acetophenone derivatives

[0060]

[0061] Compound 1b (0.5 mmol), supported ruthenium catalyst ML1-X (25 mg, containing 1 mg Ru, 1 mol%), and sodium formate (2 mmol) were added sequentially to a 10 mL Shrek tube. 2 mL of water was added as a solvent, and the reaction was carried out under argon protection at 40 °C for 8 h. After the reaction was complete, the supported catalyst was recovered by centrifugation. The product was extracted with ethyl acetate and concentrated. The residue was separated by column chromatography (ethyl acetate: n-hexane = 1:20, v / v) to obtain (S)-1-(5-fluoro-2-iodophenyl)-1-ethanol (2b). The reaction results are listed in the table below:

[0062] Table 2 Comparison of the asymmetric hydrogen transfer effect of the supported ruthenium catalyst ML1-X on acetophenone derivatives

[0063]

[0064] Table 2 compares the catalytic performance of ML1 supported catalysts and monomer catalysts with different polymer monomer compositions on acetophenone derivatives. The reaction results show that the polymer layer needs to have a certain polymer abundance to ensure that the catalytic sites are not too crowded. However, the catalytic ability is reduced as the amount of divinylbenzene increases. Thus, the most suitable polymerization ratio is: vinyl-modified diamine ligand L1(3): divinylbenzene (DVB) = 1:5 (molar ratio).

[0065] Example 4: Preparation of polymer-coated mesoporous silica-supported ruthenium catalyst ML2

[0066]

[0067] (1) Add p-methylbenzaldehyde (1 mmol) and ammonia methanol solution (15 mmol, 7 M in MeOH) to a dry 50 mL two-necked flask, add 2 mL of tetrahydrofuran to dissolve, stir at room temperature for 1 h under argon atmosphere, then add (5R,5'R)-4,4,4',4'-tetra(2,5-dimethylphenyl)-5,5'-diphenyl-2,2'-bis(1,3,2-dioxaborane) (DB7) (0.5 mmol), continue stirring at room temperature for 24 h, and concentrate to remove excess ammonia. The remaining solid was dissolved in 2 mL of methanol, and the pH was adjusted to 2-3 with 2M hydrochloric acid. Then, 5 mL of dichloromethane was added. The aqueous phase was separated by liquid chromatography, and the pH was adjusted to 7 with 2M sodium hydroxide aqueous solution. Dichloromethane was then added to dissolve the product. The product was extracted with a dichloromethane-water system, and the aqueous phase was extracted three times with dichloromethane. The organic phases were combined, dried, and concentrated to obtain (S,S)-1,2-di(4-methyl)phenylethylenediamine (yield 95.0%) as a slightly yellow solid powder.

[0068] (2) The polymer-coated mesoporous silica-supported ruthenium catalyst ML2 was prepared in a manner similar to that in Example 1, except that in the polymerization reaction of step (2) in Example 1, “(S,S)-diphenylethylenediamine (3 mmol)” was replaced with “(S,S)-di(4-methyl)phenylethylenediamine (3 mmol)” to prepare ligand L2. Then, ligand L1 in step (3) of Example 1 was replaced with an equal molar amount of ligand L2 to finally prepare the polymer-coated mesoporous silica-supported hydrogen transfer catalyst ML2 (mass yield 96.4%).

[0069] Example 4: NMR data of ligand L2:

[0070] 1 H NMR (400MHz, CDCl3): δ7.54-7.12(m,12H),6.73(dd,1H),5.82(d,1H),5.25(d,1H),4.17(s,2H),3.25(s,2H),2.11(s,6H); 13 C NMR (100MHz, CDCl3): δ143.7,141.2,140.7,136.4,136.1,128.8,125.3,127.2,126.7,125.5,59.1,55.2,20.0; ESI-MS: M / z 407.25[M+H] + HRMS(ESI)calcd.for C 16 H 21 N2[M+H] + :407.1795; found:407.1793.

[0071] Example 5: Preparation of polymer-coated mesoporous silica-supported ruthenium catalyst ML3

[0072] (1) Add p-methoxybenzaldehyde (1 mmol) and ammonia methanol solution (15 mmol, 7 M in MeOH) to a dry 50 mL two-necked flask, add 2 mL of tetrahydrofuran to dissolve, stir at room temperature for 1 h under argon atmosphere, then add (5R,5'R)-4,4,4',4'-tetra(2,5-dimethylphenyl)-5,5'-diphenyl-2,2'-bis(1,3,2-dioxaborane) (DB7) (0.5 mmol), continue stirring at room temperature for 24 h, and concentrate to remove excess ammonia. The remaining solid was dissolved in 2 mL of methanol, and the pH was adjusted to 2-3 with 2M hydrochloric acid. Then, 5 mL of dichloromethane was added. The aqueous phase was separated by liquid chromatography, and the pH was adjusted to neutral with 2M sodium hydroxide aqueous solution. Dichloromethane was then added to dissolve the product. The product was extracted with a dichloromethane-water system, and the aqueous phase was extracted three times with dichloromethane. The organic phases were combined, dried, and concentrated to obtain the product, (S,S)-1,2-bis(4-methoxy)phenylethylenediamine (yield 98.5%), which is a yellow solid powder.

[0073] (2) The polymer-coated mesoporous silica-supported ruthenium catalyst ML3 was prepared in a manner similar to that in Example 1, except that in step 3) of the polymerization reaction in Example 1, “(S,S)-1,2-diphenylethylenediamine (3 mmol)” was replaced with “(S,S)-1,2-di(4-methoxy)phenylethylenediamine (3 mmol)” to prepare ligand L3. Then, ligand L1 in step (3) of Example 1 was replaced with an equal molar amount of ligand L3 to finally prepare the polymer-coated mesoporous silica-supported hydrogen transfer catalyst ML3 (mass yield 95.7%).

[0074] NMR data for ligand L3:

[0075] 1 H NMR (400MHz, CDCl3): δ6.88-7.64(m,12H),6.76(dd,1H),5.71(d,1H),5.1 4(d,1H),4.31(d,1H),4.26(d,1H),4.05(s,6H),2.11(s,6H),3.25(s,2H); 13 CNMR (100MHz, CDCl3): δ158.6,143.9,141.2,140.7,136.1,135.4,127.2,126.7,126.6,114.3,58.2,56.4; ESI-MS: M / z 439.15[M+H] + HRMS(ESI)calcd.for C 16 H 21 N2[M+H] +:439.5501; found:439.5497.

[0076] Example 6: Preparation of polymer-coated mesoporous silica-supported ruthenium catalyst ML4

[0077] (1) Add p-tert-butylbenzaldehyde (1 mmol) and ammonia methanol solution (15 mmol, 7 M in MeOH) to a dry 50 mL two-necked flask, add 2 mL of tetrahydrofuran to dissolve, stir at room temperature for 1 h under argon atmosphere, then add (5R,5'R)-4,4,4',4'-tetra(2,5-dimethylphenyl)-5,5'-diphenyl-2,2'-bis(1,3,2-dioxaborane) (DB7) (0.5 mmol), continue stirring at room temperature for 24 h, and concentrate to remove excess ammonia. The remaining solid was dissolved in 2 mL of methanol, and the pH was adjusted to 2-3 with 2M hydrochloric acid. Then, 5 mL of dichloromethane was added. The aqueous phase was separated by liquid chromatography, and the pH was adjusted to neutral with 2M sodium hydroxide aqueous solution. Dichloromethane was then added to dissolve the product. The product was extracted with a dichloromethane-water system, and the aqueous phase was extracted three times with dichloromethane. The organic phases were combined, dried, and concentrated to obtain the product, a yellow solid powder of (S,S)-1,2-bis(4-tert-butyl)phenylethylenediamine (yield 93.6%).

[0078] (2) The polymer-coated mesoporous silica-supported ruthenium catalyst ML4 was prepared in a manner similar to that in Example 1, except that in the polymerization reaction of step (3) in Example 1, “(S,S)-1,2-diphenylethylenediamine (3 mmol)” was replaced with “(S,S)-1,2-di(4-tert-butyl)phenylethylenediamine (3 mmol)” to prepare ligand L4. Then, ligand L1 in step (3) of Example 1 was replaced with an equal molar amount of ligand L4, and finally the polymer-coated mesoporous silica-supported hydrogen transfer catalyst ML4 (mass yield 98.0%) was prepared.

[0079] NMR data for ligand L4:

[0080] 1 H NMR (400MHz, CDCl3): δ7.10-7.19(m,12H),6.91(dd,1H),5.77(d,1H),5.28(d,1H),4.26(d,2H),4.17(d,2H),1.37(s,18H); 13C NMR (100MHz, CDCl3): δ150.1,143.3,141.1,140.5,136.1,127.3,127.2,126 .7,126.2,125.6,125.3,125.0,124.8,61.4,59.4,34.2,31.3,;ESI-MS:M / z 491.28[M+H] + HRMS(ESI)calcd.for C 16 H 21 N2[M+H]+:491.2734; found:491.2730.

[0081] Example 7: Preparation of polymer-coated mesoporous silica-supported ruthenium catalyst ML5

[0082] The polymer-coated mesoporous silica-supported ruthenium catalyst ML5 was prepared in a similar manner to that in Example 1, except that in step (3), “metallic ruthenium salt [Ru(mesitylene)Cl]2,3mg” was replaced with “metallic ruthenium salt [Ru(p-cymene)Cl]2,3mg”, and the polymer-coated mesoporous silica-supported hydrogen transfer catalyst ML5 (mass yield 99.2%) was obtained.

[0083] Example 8: Comparison of the asymmetric hydrogen transfer catalytic reduction performance of supported ruthenium catalysts ML1-ML5 on β-keto ester substrates

[0084]

[0085] Compound (1a) (0.5 mmol), polymer-coated mesoporous silica-supported ruthenium catalyst MLn (n = 1–5) (25 mg, containing 1 mg Ru, 1 mol%), and sodium formate (2 mmol) were added sequentially to a 10 mL Shrek tube. 2 mL of water was added as a solvent to ensure uniform dispersion. The reaction was carried out under argon protection at 40 °C for 8 h. After the reaction, the supported catalyst was recovered by centrifugation. The product was extracted with ethyl acetate and concentrated. The residue was separated by column chromatography (ethyl acetate: n-hexane = 1:10, v / v) to obtain ethyl (S)-3-hydroxy-3-phenylpropionate (2a). The results are shown in the table below:

[0086] Table 3 Comparison of the asymmetric hydrogen transfer effects of the supported ruthenium catalyst MLn on β-keto ester substrates

[0087]

[0088] Example 9: Preparation of (S)-1-(5-fluoro-2-iodophenyl)-1-ethanol (2b)

[0089]

[0090] Compound (1b) (0.5 mmol), polymer-coated mesoporous silica-supported ruthenium catalyst ML1 (25 mg, containing 1 mg Ru, 1 mol%), and sodium formate (2 mmol) were added sequentially to a 10 mL Shrek tube. 2 mL of water was added as a solvent to ensure uniform dispersion. The reaction was carried out under argon protection at 40 °C for 8 h. After the reaction was complete, the supported catalyst was recovered by centrifugation. The product was extracted with ethyl acetate and concentrated. The residue was separated by column chromatography (ethyl acetate: n-hexane = 1:20, v / v) to obtain (S)-1-(5-fluoro-2-iodophenyl)-1-ethanol (2b), with a purity of 99%, a yield of 93%, and an ee value of 85%.

[0091] Example 10: Preparation of (S)-5,7-difluorotetrahydrobenzopyran-4-ol (2c)

[0092]

[0093] Compound (1c) (0.5 mmol), polymer-coated mesoporous silica-supported ruthenium catalyst ML1 (25 mg, containing 1 mg Ru, 1 mol%), and sodium formate (2 mmol) were added sequentially to a 10 mL Shrek tube. 2 mL of water was added as a solvent to ensure uniform dispersion. The reaction was carried out under argon protection at 40 °C for 8 h. After the reaction, the supported catalyst was recovered by centrifugation. The product was extracted with ethyl acetate and concentrated. The residue was separated by column chromatography (ethyl acetate: n-hexane = 1:10, v / v) to obtain (S)-5,7-difluorotetrahydrobenzopyran-4-ol (2c), with a purity of 99%, a yield of 98%, and an ee value of 95%.

[0094] Example 11: Preparation of ethyl (S)-3-hydroxy-3-(2-methylphenyl)propionate (2d)

[0095]

[0096] Compound (1d) (0.5 mmol), polymer-coated mesoporous silica-supported ruthenium catalyst ML1 (25 mg, containing 1 mg Ru, 1 mol%), and sodium formate (2 mmol) were added sequentially to a 10 mL Shrek tube. 2 mL of water was added as a solvent to ensure uniform dispersion. The reaction was carried out under argon protection at 40 °C for 8 h. After the reaction was complete, the supported catalyst was recovered by centrifugation. The product was extracted with ethyl acetate and concentrated. The residue was separated by column chromatography (ethyl acetate: n-hexane = 1:10, v / v) to obtain ethyl (S)-3-hydroxy-3-(2-methylphenyl)propionate (2d), with a purity of 99%, a yield of 97%, and an ee value of 90%.

[0097] Example 12: Preparation of ethyl (S)-3-hydroxy-3-(3-methylphenyl)propionate (2e)

[0098]

[0099] Compound (1e) (0.5 mmol), polymer-coated mesoporous silica-supported ruthenium catalyst ML1 (25 mg, containing 1 mg Ru, 1 mol%), and sodium formate (2 mmol) were added sequentially to a 10 mL Shrek tube. 2 mL of water was added as a solvent to ensure uniform dispersion. The reaction was carried out under argon protection at 40 °C for 8 h. After the reaction, the supported catalyst was recovered by centrifugation. The product was extracted with ethyl acetate and concentrated. The residue was separated by column chromatography (ethyl acetate: n-hexane = 1:10, v / v) to obtain ethyl (S)-3-hydroxy-3-(3-methylphenyl)propionate (2e), with a purity of 99%, a yield of 96%, and an ee value of 94%.

[0100] Example 13: Preparation of ethyl (S)-3-hydroxy-3-(4-methylphenyl)propionate (2f)

[0101]

[0102] Compound (1f) (0.5 mmol), polymer-coated mesoporous silica-supported ruthenium catalyst ML1 (25 mg, containing 1 mg Ru, 1 mol%), and sodium formate (2 mmol) were added sequentially to a 10 mL Shrek tube. 2 mL of water was added as a solvent to ensure uniform dispersion. The reaction was carried out under argon protection at 40 °C for 8 h. After the reaction was complete, the supported catalyst was recovered by centrifugation. The product was extracted with ethyl acetate and concentrated. The residue was separated by column chromatography (ethyl acetate: n-hexane = 1:10, v / v) to obtain ethyl (S)-3-hydroxy-3-(4-methylphenyl)propionate (2f), with a purity of 99%, a yield of 99%, and an ee value of 97%.

[0103] Example 14: Preparation of ethyl (S)-3-hydroxy-3-(4-isopropylphenyl)propionate (2g)

[0104]

[0105] To a 10 mL Shrek tube, compound (1 g) (0.5 mmol), polymer-coated mesoporous silica-supported ruthenium catalyst ML1 (25 mg, containing 1 mg Ru, 1 mol%), and sodium formate (2 mmol) were added sequentially. 2 mL of water was added as a solvent to ensure uniform dispersion. The reaction was carried out under argon protection at 40 °C for 8 h. After the reaction, the supported catalyst was recovered by centrifugation. The product was extracted with ethyl acetate and concentrated. The residue was separated by column chromatography (ethyl acetate: n-hexane = 1:10, v / v) to obtain ethyl (S)-3-hydroxy-3-(4-isopropylphenyl)propionate (2 g), with a purity of 99%, a yield of 95%, and an ee value of 94%.

[0106] Example 15: Preparation of ethyl (S)-3-hydroxy-3-(4-methoxyphenyl)propionate (2h)

[0107]

[0108] Compound (1h) (0.5 mmol), polymer-coated mesoporous silica-supported ruthenium catalyst ML1 (25 mg, containing 1 mg Ru, 1 mol%), and sodium formate (2 mmol) were added sequentially to a 10 mL Shrek tube. 2 mL of water was added as a solvent to ensure uniform dispersion. The reaction was carried out under argon protection at 40 °C for 8 h. After the reaction, the supported catalyst was recovered by centrifugation. The product was extracted with ethyl acetate and concentrated. The residue was separated by column chromatography (ethyl acetate: n-hexane = 1:8, v / v) to obtain ethyl (S)-3-hydroxy-3-(4-methoxyphenyl)propionate (2h), with a purity of 99%, a yield of 99%, and an ee value of 96%.

[0109] Example 16: Preparation of ethyl (S)-3-hydroxy-3-(4-fluorophenyl)propionate (2i)

[0110]

[0111] Compound (1i) (0.5 mmol), polymer-coated mesoporous silica-supported ruthenium catalyst ML1 (25 mg, containing 1 mg Ru, 1 mol%), and sodium formate (2 mmol) were added sequentially to a 10 mL Shrek tube. 2 mL of water was added as a solvent to ensure uniform dispersion. The reaction was carried out under argon protection at 40 °C for 8 h. After the reaction, the supported catalyst was recovered by centrifugation. The product was extracted with ethyl acetate and concentrated. The residue was separated by column chromatography (ethyl acetate: n-hexane = 1:5, v / v) to obtain ethyl (S)-3-hydroxy-3-(4-fluorophenyl)propionate (2i), with a purity of 99%, a yield of 94%, and an ee value of 92%.

[0112] Example 17: Preparation of ethyl (S)-3-hydroxy-3-(4-chlorophenyl)propionate (2j)

[0113]

[0114] Compound (1j) (0.5 mmol), polymer-coated mesoporous silica-supported ruthenium catalyst ML1 (25 mg, containing 1 mg Ru, 1 mol%), and sodium formate (2 mmol) were added sequentially to a 10 mL Shrek tube. 2 mL of water was added as a solvent to ensure uniform dispersion. The reaction was carried out under argon protection at 40 °C for 8 h. After the reaction, the supported catalyst was recovered by centrifugation. The product was extracted with ethyl acetate and concentrated. The residue was separated by column chromatography (ethyl acetate: n-hexane = 1:5, v / v) to obtain ethyl (S)-3-hydroxy-3-(4-chlorophenyl)propionate (2j), with a purity of 99%, a yield of 94%, and an ee value of 99%.

[0115] Example 18: Preparation of ethyl (S)-3-hydroxy-3-(4-bromophenyl)propionate (2k)

[0116]

[0117] To a 10 mL Shrek tube, the substrate (1k) (0.5 mmol), polymer-coated mesoporous silica-supported ruthenium catalyst ML1 (25 mg, containing 1 mg Ru, 1 mol%), and sodium formate (2 mmol) were added sequentially. 2 mL of water was added as a solvent to ensure uniform dispersion. The reaction was carried out under argon protection at 40 °C for 8 h. After the reaction, the supported catalyst was recovered by centrifugation. The product was extracted with ethyl acetate and concentrated. The residue was separated by column chromatography (ethyl acetate: n-hexane = 1:5, v / v) to obtain ethyl (S)-3-hydroxy-3-(4-bromophenyl)propionate (2k), with a purity of 99%, a yield of 99%, and an ee value of 90%.

[0118] Example 19: Preparation of ethyl (S)-3-hydroxy-3-(4-trifluoromethylphenyl)propionate (2l)

[0119]

[0120] Compound (1 l) (0.5 mmol), polymer-coated mesoporous silica-supported ruthenium catalyst ML1 (25 mg, containing 1 mg Ru, 1 mol%), and sodium formate (2 mmol) were added sequentially to a 10 mL Shrek tube. 2 mL of water was added as a solvent to ensure uniform dispersion. The reaction was carried out under argon protection at 40 °C for 8 h. After the reaction, the supported catalyst was recovered by centrifugation. The product was extracted with ethyl acetate and concentrated. The residue was separated by column chromatography (ethyl acetate: n-hexane = 1:10, v / v) to obtain ethyl (S)-3-hydroxy-3-(4-trifluoromethylphenyl)propionate (2 l), with a purity of 99%, a yield of 97%, and an ee value of 95%.

[0121] Example 20: Preparation of ethyl (S)-3-hydroxy-3-([1,1'-biphenyl]-4-yl)propionate (2m)

[0122]

[0123] Compound (1m) (0.5 mmol), polymer-coated mesoporous silica-supported ruthenium catalyst ML1 (25 mg, containing 1 mg Ru, 1 mol%), and sodium formate (2 mmol) were added sequentially to a 10 mL Shrek tube. 2 mL of water was added as a solvent to ensure uniform dispersion. The reaction was carried out under argon protection at 40 °C for 8 h. After the reaction, the supported catalyst was recovered by centrifugation. The product was extracted with ethyl acetate and concentrated. The residue was separated by column chromatography (ethyl acetate: n-hexane = 1:10, v / v) to obtain ethyl (S)-3-hydroxy-3-([1,1'-biphenyl]-4-yl)propionate (2m), with a purity of 99%, a yield of 99%, and an ee value of 95%.

[0124] Example 21: Preparation of ethyl (S)-3-hydroxy-3-(2-naphthyl)propionate (2n)

[0125]

[0126] Compound (1n) (0.5 mmol), polymer-coated mesoporous silica-supported ruthenium catalyst ML1 (25 mg, containing 1 mg Ru, 1 mol%), and sodium formate (2 mmol) were added sequentially to a 10 mL Shrek tube. 2 mL of water was added as a solvent to ensure uniform dispersion. The reaction was carried out under argon protection at 40 °C for 8 h. After the reaction, the supported catalyst was recovered by centrifugation. The product was extracted with ethyl acetate and concentrated. The residue was separated by column chromatography (ethyl acetate: n-hexane = 1:10, v / v) to obtain ethyl (S)-3-hydroxy-3-(2-naphthyl)propionate (2n) with a purity of 99%, a yield of 90%, and an ee value of 96%.

[0127] Example 22: Preparation of (S)-3-hydroxy-3-diferrocene ethyl propionate (2o)

[0128]

[0129] Compound (1o) (0.5 mmol), polymer-coated mesoporous silica-supported ruthenium catalyst ML1 (25 mg, containing 1 mg Ru, 1 mol%), and sodium formate (2 mmol) were added sequentially to a 10 mL Shrek tube. 2 mL of water was added as a solvent to ensure uniform dispersion. The reaction was carried out under argon protection at 40 °C for 8 h. After the reaction, the supported catalyst was recovered by centrifugation. The product was extracted with ethyl acetate and concentrated. The residue was separated by column chromatography (ethyl acetate: n-hexane = 1:10, v / v) to obtain (S)-3-hydroxy-3-diferrocene propionate ethyl ester (2o), with a purity of 99%, a yield of 99%, and an ee value of 96%.

[0130] Example 23: Preparation of ethyl (S)-3-hydroxy-3-(2-furanyl)propionate (2p)

[0131]

[0132] Compound (1p) (0.5 mmol), polymer-coated mesoporous silica-supported ruthenium catalyst ML1 (25 mg, containing 1 mg Ru, 1 mol%), and sodium formate (2 mmol) were added sequentially to a 10 mL Shrek tube. 2 mL of water was added as a solvent to ensure uniform dispersion. The reaction was carried out under argon protection at 40 °C for 8 h. After the reaction, the supported catalyst was recovered by centrifugation. The product was extracted with ethyl acetate and concentrated. The residue was separated by column chromatography (ethyl acetate: n-hexane = 1:10, v / v) to obtain ethyl (S)-3-hydroxy-3-(2-furanyl)propionate (2p), with a purity of 99%, a yield of 97%, and an ee value of 96%.

[0133] Example 24: Preparation of ethyl (S)-3-hydroxy-3-(2-thienyl)propionate (2q)

[0134]

[0135] Compound (1q) (0.5 mmol), polymer-coated mesoporous silica-supported ruthenium catalyst ML1 (25 mg, containing 1 mg Ru, 1 mol%), and sodium formate (2 mmol) were added sequentially to a 10 mL Shrek tube. 2 mL of water was added as a solvent to ensure uniform dispersion. The reaction was carried out under argon protection at 40 °C for 8 h. After the reaction, the supported catalyst was recovered by centrifugation. The product was extracted with ethyl acetate and concentrated. The residue was separated by column chromatography (ethyl acetate: n-hexane = 1:10, v / v) to obtain ethyl (S)-3-hydroxy-3-(2-thienyl)propionate (2q), with a purity of 99%, a yield of 96%, and an ee value of 96%.

[0136] Example 25: Preparation of ethyl (S)-3-hydroxy-3-(benzo[d][1,3]dioxono-5-yl)propionate (2r)

[0137]

[0138] Compound (1r) (0.5 mmol), polymer-coated mesoporous silica-supported ruthenium catalyst ML1 (25 mg, containing 1 mg Ru, 1 mol%), and sodium formate (2 mmol) were added sequentially to a 10 mL Shrek tube. 2 mL of water was added as a solvent to ensure uniform dispersion. The reaction was carried out under argon protection at 40 °C for 8 h. After the reaction, the supported catalyst was recovered by centrifugation. The product was extracted with ethyl acetate and concentrated. The residue was separated by column chromatography (ethyl acetate: n-hexane = 1:10, v / v) to obtain ethyl (S)-3-hydroxy-3-(benzo[d][1,3]dioxonol-5-yl)propionate (2r), with a purity of 99%, a yield of 99%, and an ee value of 93%.

[0139] Example 26: Preparation of ethyl (S)-3-hydroxy-3-(3,5-dimethylphenyl)propionate (2S)

[0140]

[0141] Compound (1s) (0.5 mmol), polymer-coated mesoporous silica-supported ruthenium catalyst ML1 (25 mg, containing 1 mg Ru, 1 mol%), and sodium formate (2 mmol) were added sequentially to a 10 mL Shrek tube. 2 mL of water was added as a solvent to ensure uniform dispersion. The reaction was carried out under argon protection at 40 °C for 8 h. After the reaction, the supported catalyst was recovered by centrifugation. The product was extracted with ethyl acetate and concentrated. The residue was separated by column chromatography (ethyl acetate: n-hexane = 1:10, v / v) to obtain ethyl (S)-3-hydroxy-3-(3,5-dimethylphenyl)propionate (2s), with a purity of 99%, a yield of 99%, and an ee value of 94%.

[0142] Example 27: Preparation of (S)-3-hydroxy-3-phenylpropionate methyl ester (2t)

[0143]

[0144] To a 10 mL Shrek tube, compound (1 t) (0.5 mmol), polymer-coated mesoporous silica-supported ruthenium catalyst ML1 (25 mg, containing 1 mg Ru, 1 mol%), and sodium formate (2 mmol) were added sequentially. 2 mL of water was added as a solvent to ensure uniform dispersion. The reaction was carried out under argon protection at 40 °C for 8 h. After the reaction, the supported catalyst was recovered by centrifugation. The product was extracted with ethyl acetate and concentrated. The residue was separated by column chromatography (ethyl acetate: n-hexane = 1:10, v / v) to obtain methyl (S)-3-hydroxy-3-phenylpropionate (2 t), with a purity of 99%, a yield of 90%, and an ee value of 95%.

[0145] Example 28: Preparation of (S)-2-ethoxybenzyl-3-hydroxy-3-phenylpropionate (2u)

[0146]

[0147] To a 10 mL Shrek tube, compound (1 u) (0.5 mmol), polymer-coated mesoporous silica-supported ruthenium catalyst ML1 (25 mg, containing 1 mg Ru, 1 mol%), and sodium formate (2 mmol) were added sequentially. 2 mL of water was added as a solvent to ensure uniform dispersion. The reaction was carried out under argon protection at 40 °C for 8 h. After the reaction, the supported catalyst was recovered by centrifugation. The product was extracted with ethyl acetate and concentrated. The residue was separated by column chromatography (ethyl acetate: n-hexane = 1:10, v / v) to obtain (S)-2-ethoxybenzyl-3-hydroxy-3-phenylpropionate (2 u), with a purity of 99%, a yield of 92%, and an ee value of 95%.

[0148] Example 29: Preparation of (S)-2-ethoxybenzyl-3-hydroxy-3-phenylpropionate (2u)

[0149]

[0150] Compound (1 v) (0.5 mmol), polymer-coated mesoporous silica-supported ruthenium catalyst ML1 (25 mg, containing 1 mg Ru, 1 mol%), and sodium formate (2 mmol) were added sequentially to a 10 mL Shrek tube. 2 mL of water was added as a solvent to ensure uniform dispersion. The reaction was carried out under argon protection at 40 °C for 8 h. After the reaction, the supported catalyst was recovered by centrifugation. The product was extracted with ethyl acetate and concentrated. The residue was separated by column chromatography (ethyl acetate: n-hexane = 1:10, v / v) to obtain (S)-2-ethoxybenzyl-3-hydroxy-3-phenylpropionate (2 u), with a purity of 99%, a yield of 92%, and an ee value of 93%.

[0151] 1 H-NMR (400MHz, CDCl3) δ7.39(m,4H),7.31(m,1H),5.14(dd,J=3.2,7.6Hz,1H),4.76(td,J=4.4,10.8Hz,1H),3.39(br s,1H),2.77(m,2H),1.99(m,2H),1.72(m,3H),1.51(m,1H),1.37(m,1H),0.93(m,9H),0.74(d,J=6.8Hz,3H). 13 CNMR(100MHz, CDCl3)δ172.2,142.5,128.5,127.7,125.7,74.9,70.3,46.9,43.4,40.9,34.2,31.4,26.2,23.4,22.0,20.7,16.3.HRMS(ESI)calcd for C 19 H 28 O3[M+H] + :304.2038,found:304.2033.

[0152] Example 30: Performance test of recycling of supported ruthenium catalyst ML1

[0153]

[0154] Following the experimental procedure described in Example 8, catalyst ML1 was washed with 1 mL of water and 1 mL of methanol after centrifugation, dried, and then added to the reaction. This reaction was repeated. During the 7th cycle, the yield significantly decreased, indicating metal loss. In the 8th cycle, 0.1 mol% of fresh catalyst was added, and the yield returned to normal. The experimental results are listed in the table below:

[0155] Table 3. Recovery and reuse experiments of the supported ruthenium catalyst ML1

[0156] Loop count 2a Yield (%) 2aee(%) 1 99 96 2 97 95.5 3 96 95.5 4 95 95.5 5 95 96 6 92 96.5 7 86 96.5 8 99 96.5

[0157] The contents described in this specification are merely an enumeration of the implementation forms of the inventive concept, and the scope of protection of this invention should not be regarded as limited to the specific forms described in the embodiments.

Claims

1. A polymer-coated mesoporous silica-supported ruthenium catalyst, characterized in that, A polymer-encapsulated mesoporous silica core, wherein the surface of the silica core is grafted with an alkenyl triethoxysilane, the alkenyl group of the triethoxysilane serving as the active site, is polymerized with a polymer monomer to form the polymer, and further coordinated and supported with metallic Ru to form the catalyst, the structure of which is shown in general formula I: ； In general formula I, R 1 Selected from one of the following: hydrogen, C1-C6 straight-chain or branched alkyl, C1-C6 alkoxy; R 2 Selected from p-methylisopropylphenyl and mesitylene; n 1 n 2 It is a positive integer.

2. The method for preparing a polymer-coated mesoporous silica-supported ruthenium catalyst as described in claim 1, characterized in that, Includes the following steps: 1) Mesoporous silica and vinyltriethoxysilane react to obtain modified mesoporous silica material 3'; 2) Modified mesoporous silica material 3', organic ligand 3, and divinylbenzene DVB were copolymerized under the condition of azobisisobutyronitrile (AIBN) as an initiator to obtain a carrier L supporting the ligand; 3) The support L of the ligand is complexed with a ruthenium metal salt to obtain the supported ruthenium catalyst shown in general formula I; 、 ； In the structural formula of organic ligand 3, Ar represents a substituted phenyl group, and the substituents on the benzene ring of the substituted phenyl group correspond to R in the general formula I. 1 same.

3. The method for preparing a polymer-coated mesoporous silica-supported ruthenium catalyst as described in claim 2, characterized in that, In step 1), the reaction is carried out in toluene under an inert atmosphere at a temperature of 60-90 °C for 8-15 h. The mass ratio of mesoporous silica to vinyltriethoxysilane is 1.5-4:

1. After the reaction is completed, deionized water is added to precipitate the solid. After filtration, the solid is washed with ethanol and dried under vacuum to obtain the modified mesoporous silica material 3'.

4. The method for preparing a polymer-coated mesoporous silica-supported ruthenium catalyst as described in claim 3, characterized in that, The mass ratio of mesoporous silica to vinyltriethoxysilane is 2-3:

1.

5. The method for preparing a polymer-coated mesoporous silica-supported ruthenium catalyst as described in claim 2, characterized in that, The organic ligand 3 mentioned in step 2) is specifically any one of the following: 。 6. The method for preparing a polymer-coated mesoporous silica-supported ruthenium catalyst as described in claim 2, characterized in that, Step 2) The mass ratio of modified mesoporous silica material 3' to organic ligand 3 is 1:0.3~0.8; the molar ratio of DVB to organic ligand 3 is 3-20:1; the mass of AIBN is 10-30% of the mass of organic ligand 3; the reaction is carried out in tetrahydrofuran at a temperature of 60~100°C. o C, the reaction time is 8~48 h, after the reaction is completed, deionized water is added to precipitate the solid, filter it, wash it with ethanol, and dry it to obtain the support L.

7. The method for preparing a polymer-coated mesoporous silica-supported ruthenium catalyst as described in claim 2, characterized in that, Step 2) The mass ratio of modified mesoporous silica material 3' to organic ligand 3 is 1:0.4-0.5; the molar ratio of DVB to organic ligand 3 is 5-15:

1.

8. The method for preparing a polymer-coated mesoporous silica-supported ruthenium catalyst as described in claim 2, characterized in that, In step 3), the mass ratio of ruthenium metal salt to support L is 1:6-10. The reaction is carried out in methanol solution at a temperature of 25-50 °C for 0.5-2 h.

9. The method for preparing a polymer-coated mesoporous silica-supported ruthenium catalyst as described in claim 8, characterized in that, The ruthenium metal salt is [Ru(mesitylene)Cl]2 or [Ru(p-cymene)Cl]2.

10. The application of the polymer-coated mesoporous silica-supported ruthenium catalyst as described in claim 1 in asymmetric hydrogen transfer reduction reactions.

11. The application as described in claim 10, characterized in that... A carbonyl compound and a supported ruthenium catalyst were dispersed in water, and a hydrogen source was added. The reaction was carried out under an inert gas atmosphere at a temperature of 25–50 °C. o C, through reaction and purification, a highly enantioselective chiral hydroxyl compound was prepared, and the supported ruthenium catalyst was recovered by centrifugation.

12. The application as described in claim 11, characterized in that... The hydrogen source is one of formic acid / triethylamine, sodium formate, isopropanol, and methanol in a volume ratio of 1-2.5:1, and the molar ratio of the hydrogen source to the carbonyl compound is 2.2-6:1.

Images