Method for synthesizing silanol through polyacid catalytic oxidation of silane

Abstract

The invention relates to the field of organic chemistry, in particular to a method for synthesizing silanol through polyacid catalytic oxidation of silane. According to the invention, hydrosilane is taken as a raw material, polyoxometallate is taken as a catalyst, and hydrosilane can be catalytically oxidized into silanol in the presence of an oxidant. The synthesis method provided by the invention is simple to operate and mild in condition, is a synthesis method of the silanol compound with atom economy and environmental friendliness, and has popularization and utilization values because the synthesis of the silanol compound is high in selectivity and the catalyst has the characteristics of greenness, high efficiency, easiness in recycling and the like.

Description

Technical Field

[0001] The present invention relates to the field of organic chemistry, and particularly to a method for synthesizing silanols by polyacid-catalyzed oxidation of silanes. Background Art

[0002] Silanols are structural analogues of alcohols, and siloxanol is a compound containing a siloxane group in addition to the Si-OH group in silanols. Silanols are a very important and valuable class of compounds. In materials chemistry, silanols can be used as synthetic building blocks for silicon-based polymer materials; in medicinal chemistry, silanols can be used as bioisosteres of alcohols; in organic synthesis methodology, silanols can serve as both coupling reagents and directing groups for C-H activation, and can even act as organic small molecule catalysts.

[0003] Currently, the synthesis of silanols mainly proceeds through three methods: one is the hydrolysis of chlorosilanes. However, HCl is generated during the hydrolysis of chlorosilanes to silanols. Under acidic conditions, two or more molecules of silanols are prone to self-condensation to form siloxanes, complicating the reaction. Therefore, the method of hydrolyzing chlorosilanes yields a mixture of silanols and siloxanes, and it is impossible to synthesize silanols containing acid-sensitive groups; the second is the oxidation of silanes with stoichiometric strong oxidants. The conversion from silanes to silanols can also be achieved by using stoichiometric strong oxidants. Currently, strong oxidants that can be used for the oxidation of silanes include silver salts, permanganates, osmium tetroxide, dioxirane, peracids, ozone, etc. However, due to the use of strong oxidants in such methods, the chemoselectivity of the reaction is very poor and equivalent amounts of waste are still generated. For example, when oxidizing silanes with potassium permanganate salts, this method will simultaneously produce silanols and siloxanes and form by-products such as MnO 2 etc.; the third is the hydrolytic oxidation with water as the oxidant. Although water is an ideal oxidant, such methods still have certain limitations. Usually, precious metals (Rh, Ru, Pd, Au, Ag, etc.) are required as reaction catalysts, and during the hydrolytic oxidation process, due to the competitive reaction between silanes and silanols, the generation of siloxanes is inevitable. In addition to H 2 O, O 2 or H 2 O 2 can also be used for the catalytic oxidation of silanes, but there are still problems such as substrate limitations, poor selectivity, and the need to use a large amount of H 2 O 2 etc.

[0004] With the continuous strengthening of people's environmental awareness, processes with low content will be gradually phased out, and it is urgent to develop an efficient method for synthesizing silanols. Summary of the Invention

[0005] In view of the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide a method for synthesizing silanol compounds with high activity, high selectivity, mild reaction conditions, green and environmental protection, and the catalyst can be recycled, which has great potential for industrial production.

[0006] To achieve the above object and other related objects, the present invention provides a method for synthesizing silanol by catalytic oxidation of silane with polyoxometalate. After reacting a polyoxometalate catalyst, a hydrosilane shown in Formula I, an oxidant and an organic solvent, the mixture is filtered to recover the polyoxometalate catalyst, and the filtrate is separated and purified to obtain silanol shown in Formula II:

[0007]

[0008] Among them, when R in Formula I 1 is H, R' in Formula II is OH; when R in Formula I 1 is selected from any one of C1-C4 alkyl, phenyl, substituted phenyl, benzyl, and substituted benzyl, R' in Formula II is the same as R in Formula I 1 ;

[0009] R 2 is independently selected from any one of C1-C4 alkyl, phenyl, substituted phenyl, benzyl, and substituted benzyl;

[0010] R 3 is independently selected from any one of C1-C4 alkyl, phenyl, substituted phenyl, benzyl, and substituted benzyl;

[0011] The substituents in the substituted phenyl and substituted benzyl are any one of C1-C4 alkyl, C1-C4 alkoxy, halogen or hydrosilyl;

[0012] The polyoxometalate catalyst is an Anderson-type polyoxometalate with Co as the central atom.

[0013] In some embodiments of the present invention, the structural formula of the Anderson-type polyoxometalate with Co as the central atom is shown in Formula III as follows:

[0014]

[0015] In some embodiments of the present invention, the organic solvent is selected from tetrahydrofuran.

[0016] In some embodiments of the present invention, based on the Si-H bond in the hydrosilane, the dosage of the polyoxometalate catalyst is 4 mol% to 6 mol%.

[0017] In some embodiments of the present invention, the dosage ratio of the organic solvent to the hydrosilane is (10-15) mL:1 mmol.

[0018] In some embodiments of the present invention, the oxidant is hydrogen peroxide, and the molar ratio of hydrogen peroxide to hydrosilane is 1.5 - 3:1.

[0019] In some embodiments of the present invention, the hydrosilane is selected from aromatic silanes, the reaction temperature is room temperature, and the reaction time is 5 - 8 h.

[0020] In some embodiments of the present invention, the hydrosilane is selected from alkyl silanes, the reaction temperature is 50 - 70 °C, and the reaction time is 18 - 30 h.

[0021] In some embodiments of the present invention, the polyoxometalate catalyst, the hydrosilane shown in formula I, the oxidant, and the organic solvent are placed in a reactor for reaction.

[0022] In some embodiments of the present invention, the recovery of the polyoxometalate catalyst specifically includes that after the reaction system is cooled to room temperature, filtration is carried out, the filter residue is collected, and the filter residue can be reused after washing, centrifugation, and drying.

[0023] In some embodiments of the present invention, the separation and purification is column chromatography. The target product is collected, the solvent is removed to obtain silanol; preferably, the method for removing the solvent is vacuum distillation.

[0024] In some embodiments of the present invention, the eluent for column chromatography is a mixed solution of petroleum ether and ethyl acetate with a volume ratio of 50 - 100:1.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The method for synthesizing silanol by polyacid-catalyzed oxidation of silane provided by the present invention uses an Anderson-type polyoxometalate with Co as the central atom as a catalyst, which has high catalytic activity and selectivity. For example, the conversion rate of triphenylsilane is more than 98%, the selectivity is about 100%, the catalyst dosage is low, and it can be recycled multiple times after simple treatment, significantly reducing the harm to equipment and controlling the corrosiveness, which is beneficial to industrial production.

[0027] 2. The method for synthesizing silanol by polyacid-catalyzed oxidation of silane provided by the present invention is simple to operate and has mild conditions. It is a method for silanol compounds with atom economy and environmental friendliness. Since the synthesis of silanol compounds has high selectivity, and the catalyst has the characteristics of being green, efficient, and easy to recycle, it has the value of popularization and utilization. Specific Embodiments

[0028] To make the object, technical solutions and beneficial technical effects of the present invention clearer, the present invention will be further described in detail below in conjunction with embodiments. Those familiar with this technology can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0029] The inventors of the present invention found that an Anderson-type polyoxometalate catalyst with Co as the central atom can catalytically oxidize hydrosilane to silanol, with high activity and high selectivity. Based on this, the present invention was completed.

[0030] The present invention provides a method for synthesizing silanol by polyacid-catalyzed oxidation of silane. After reacting a polyoxometalate catalyst, a hydrosilane represented by formula I, an oxidant and an organic solvent, the mixture is filtered to recover the polyoxometalate catalyst, and the filtrate is separated and purified to obtain a silanol represented by formula II:

[0031]

[0032] Among them, when R in formula I 1 is H, R' in formula II is OH; when R in formula I 1 is selected from any one of C1-C4 alkyl, phenyl, substituted phenyl, benzyl, and substituted benzyl, R' in formula II is the same as R in formula I 1 ;

[0033] R 2 is independently selected from any one of C1-C4 alkyl, phenyl, substituted phenyl, benzyl, and substituted benzyl;

[0034] R 3 is independently selected from any one of C1-C4 alkyl, phenyl, substituted phenyl, benzyl, and substituted benzyl;

[0035] The substituents in the substituted phenyl and substituted benzyl are any one of C1-C4 alkyl, C1-C4 alkoxy, halogen or hydrosilyl;

[0036] The polyoxometalate catalyst is an Anderson-type polyoxometalate with Co as the central atom.

[0037] In the present invention, the term "alkyl" generally refers to saturated aliphatic groups, which can be straight-chain or branched-chain. For example, C1-C4 alkyl generally refers to alkyl groups containing 1, 2, 3, or 4 carbon atoms, and the alkyl groups can specifically be methyl, ethyl, propyl, n-propyl, isopropyl, butyl, n-butyl, isobutyl, tert-butyl, etc.

[0038] In the present invention, the term "alkoxy" generally refers to an alkyl-O-group, where the alkyl is as defined above. For example, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy and heptyloxy. The bond to the parent moiety is through the ether oxygen.

[0039] In the present invention, the term "halogen" generally refers to F, Cl, Br or I.

[0040] In the present invention, the term "hydrosilyl" generally refers to a monovalent group formed by removing one hydrogen atom from an organohydrosilane and may have at least 1 hydrogen atom. For example, -SiHMe 2 , -SiHEt 2 and so on.

[0041] Polyoxometalates (POMs, also known as polyacids) are nanoscale metal-oxygen cluster compounds formed by the high oxidation states of early transition metal ions (such as V, Mo, W, etc.) and oxygen. As a new type of highly efficient and multifunctional catalyst, polyoxometalates have both acid catalytic properties and redox catalytic properties, and have good stability. They can be used in both homogeneous reactions and heterogeneous reactions, and even can be used as phase transfer catalysts. They are a class of very promising green and environmentally friendly catalysts and are widely used in the fields of catalysis, analysis, pharmaceuticals, electrochemistry, photochemistry and petrochemistry, etc., with the advantages of high activity, high selectivity, high stability and recyclability. The polyoxometalate catalyst described in the present invention is an Anderson-type polyoxometalate with Co as the central atom, and its molecular formula is (NH 4 ) 3 [Co(OH) 6 Mo 6 O 18 , and its structural formula is shown as Formula III below:

[0042]

[0043] In the present invention, the organic solvent is usually a good solvent for the reaction system, so that the reactants are fully dispersed and a certain concentration is ensured to enable the reaction to proceed smoothly. In some embodiments of the present invention, the organic solvent is selected from tetrahydrofuran.

[0044] In some embodiments of the present invention, based on the Si-H bond in the hydrosilane, the dosage of the polyoxometalate catalyst is 4 mol% to 6 mol%, and can be 4 mol% to 4.2 mol%, 4.2 mol% to 4.4 mol%, 4.4 mol% to 4.6 mol%, 4.6 mol% to 4.8 mol%, 4.8 mol% to 5 mol%, 5 mol% to 5.2 mol%, 5.2 mol% to 5.4 mol%, 5.4 mol% to 5.6 mol%, 5.6 mol% to 5.8 mol%, and can also be 5.8 mol% to 6 mol%; preferably 5 mol%. In particular, when R in the silane 1When it is H, since 1 mol of hydrosilane contains 2 mol of Si-H bonds, the dosage of the polyoxometalate catalyst is preferably 10 mol%.

[0045] In some embodiments of the present invention, the dosage ratio of the organic solvent to the hydrosilane is (10 - 15) mL: 1 mmol, and it can be (10 - 11) mL: 1 mmol, (11 - 12) mL: 1 mmol, (12 - 13) mL: 1 mmol, (13 - 14) mL: 1 mmol, or can also be (14 - 15) mL: 1 mmol.

[0046] In some embodiments of the present invention, the oxidant is hydrogen peroxide, and the molar ratio of hydrogen peroxide to hydrosilane is 1.5 - 3: 1, and it can be 1.5 - 2: 1, 2 - 2.5: 1, or can also be 2.5 - 3: 1, and preferably 2: 1.

[0047] In the present invention, the reaction temperature is the temperature condition for the reaction to proceed fully in the forward direction. In some embodiments of the present invention, the hydrosilane is selected from aromatic silanes, such as dimethylphenylsilane, triphenylsilane, diphenyldihydrosilane, benzyldimethylsilane, tribenzylsilane, etc., the reaction temperature is room temperature, and the reaction time is 5 - 8 h, and it can be 5 - 5.5 h, 5.5 - 6 h, 6 - 6.5 h, 6.5 - 7 h, 7 - 7.5 h, or can also be 7.5 - 8 h.

[0048] In some embodiments of the present invention, the hydrosilane is selected from alkyl silanes, such as trimethylsilane, triethylsilane, triisopropylsilane, etc., the reaction temperature is 50 - 70 °C, and it can be 50 - 55 °C, 55 - 60 °C, 60 - 65 °C, or can also be 65 - 70 °C; the reaction time is 18 - 30 h, and it can be 18 - 20 h, 20 - 22 h, 22 - 24 h, 24 - 26 h, 26 - 28 h, or can also be 28 - 30 h.

[0049] In some embodiments of the present invention, the polyoxometalate catalyst, the hydrosilane shown in formula I, the oxidant, and the organic solvent are placed in a reactor for reaction. There is no special limitation on the reactor, and it can meet the corresponding functions.

[0050] In the present invention, stirring is included during the reaction process. There is no special limitation on the stirring, and it can be mechanical stirring or magnetic stirring, and preferably magnetic stirring.

[0051] In some embodiments of the present invention, the recovery of the polyoxometalate catalyst specifically includes that after the reaction system is cooled to room temperature, filtration is carried out, the filter residue is collected, and the filter residue can be reused after washing, centrifugation, and drying. The detergent is usually the same as the organic solvent used in the reaction system, such as tetrahydrofuran.

[0052] In the present invention, the separation and purification refers to post-treating the reaction product by selecting a suitable method. In some embodiments of the present invention, the separation and purification is column chromatography. The target product is collected, the solvent is removed, and silanol is obtained. Preferably, the method for removing the solvent is vacuum distillation, and more preferably rotary evaporation.

[0053] In some embodiments of the present invention, the eluent for column chromatography is a mixed solution of petroleum ether and ethyl acetate with a volume ratio of 50-100:1, which can be 50-60:1, 60-70:1, 70-80:1, 80-90:1, or 90-100:1.

[0054] The present invention will be further illustrated by the following examples, but the scope of the present invention is not limited thereby.

[0055] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those skilled in the art of this technology. Except for the specific methods, equipment, and materials used in the examples, according to the knowledge of those skilled in the art of this technology and the description of the present invention, any methods, equipment, and materials of the prior art similar to or equivalent to those described in the embodiments of the present invention can also be used to implement the present invention.

[0056] Example 1

[0057] Synthesis of Triphenylsilanol

[0058] Triphenylsilane (52.02 mg, 0.2 mmol), a 5 mol% Anderson-type polyoxometalate catalyst with Co as the central atom, and hydrogen peroxide (2.0 equiv, 0.0136 g) were dissolved in 3 mL of tetrahydrofuran and placed in a 25 mL pressure-resistant tube. The mixture was stirred at room temperature for 6 h. After the reaction was completed, it was cooled to room temperature, filtered, the filter residue was recycled, the filtrate was concentrated, and column chromatography separation was carried out. It was eluted with a mixed solution of petroleum ether / ethyl acetate (v:v) = 100:1, the target product was collected, and the solvent was dried by rotary evaporation to obtain 54.12 mg of the product, with a yield of 98%.

[0059] 1 H NMR (600 MHz, Chloroform-d) δ 7.51–7.47 (m, 6H), 7.34–7.30 (m, 3H), 7.30–7.25 (m, 7H), 5.39 (s, 1H); 13 C NMR (151 MHz, Chloroform-d) δ 134.76, 132.26, 128.77, 127.00 ppm. HRMS m / z (ESI) calcd for C 18 H16 OSi[M+H] + : 277.1049, found:277.1048.

[0060] The product structural formula is as follows:

[0061]

[0062] Example 2

[0063] Synthesis of triisopropylsilanol

[0064] According to the synthesis method described in Example 1, the difference is that the substrate used is triisopropylsilane (31.67 mg, 0.2 mmol), the reaction temperature is 60 °C, and the reaction is stirred for 24 h to obtain 32.43 mg of the product, and the yield is 93%.

[0065] 1 H NMR (600 MHz, Chloroform-d6) δ 1.04 (s, 21H), 1.49 (brs, 1H); 13 C NMR (151 MHz, Chloroform-d6) δ 12.2, 17.6 ppm. HRMS m / z (ESI) calcd for C 9 H 22 OSi[M+H] + : 175.1518, found:175.1520.

[0066] The product structural formula is as follows:

[0067]

[0068] Example 3

[0069] Synthesis of triethylsilanol

[0070] According to the synthesis method described in Example 1, the difference is that the substrate used is triethylsilane (23.26 mg, 0.2 mmol), the reaction temperature is 60 °C, and the reaction is stirred for 24 h to obtain 25.42 mg of the product, and the yield is 67%.

[0071] 1 H NMR (600 MHz, Chloroform-d 6 ) δ 0.57–0.63 (q, J = 8 Hz, 6H), 0.97 (t, J = 8 Hz, 9H), 1.26 (brs, 1H); 13 C NMR (151 MHz, Chloroform-d 6) δ 5.7, 6.5 ppm. HRMS m / z (ESI) calcd for C 6 H 16 OSi [M + H] + : 133.1049, found:133.1049.

[0072] The structural formula of the product is as follows:

[0073]

[0074] Example 4

[0075] Synthesis of diphenylsilanediol

[0076] According to the synthesis method described in Example 1, the difference is that the substrate used is diphenyldihydrosilane (36.46 mg, 0.2 mmol), and 42.34 mg of the product is obtained, with a yield of 70%.

[0077] 1 H NMR (600 MHz, Chloroform - d 6 ) δ 7.45 (dd, J = 8.0, 1.4 Hz, 4H), 7.33 (ddd, J = 7.1, 4.2, 1.4 Hz, 2H), 7.16 (t, J = 7.6 Hz, 4H), 13 C NMR (151 MHz, Chloroform - d 6 ) δ 134.4, 134.3, 130.0, 127.6 ppm. HRMS m / z (ESI) calcd for C 12 H 12 O 2 Si [M + H] + : 217.0685, found:217.0687.

[0078] The structural formula of the product is as follows:

[0079]

[0080] Example 5

[0081] Synthesis of benzyldimethylsilanol

[0082] According to the synthesis method described in Example 1, the difference is that the substrate used is benzyldimethylsilane (30.06 mg, 0.2 mmol), and 31.22 mg of the product is obtained, with a yield of 94%.

[0083] 1 H NMR (600 MHz, Chloroform - d 6) δ 0.15 (s, 6H), 1.71 (brs, 1H), 2.19 (s, 2H), 7.06–7.12 (m, 3H), 7.23–7.26 ppm (m, 2H). 13 C NMR (151 MHz, Chloroform-d 6 ) δ -0.7, 28.0, 124.2, 128.1, 128.4, 138.9 ppm. HRMS m / z (ESI) calcd for C 9 H 14 OSi [M + H] + : 167.0892, found:167.0890. The structure formula of the product is as follows:

[0084]

[0085] Example 6

[0086] Synthesis of dimethylphenylsilanol

[0087] According to the synthesis method described in Example 1, the difference is that the substrate used is dimethylphenylsilane (27.25 mg, 0.2 mmol), and 29.50 mg of the product is obtained with a yield of 97%.

[0088] 1 H NMR (600 MHz, Chloroform-d 6 ) δ 0.42 (s, 6H), 2.03 (brs, 1H), 7.42–7.38 (m, 3H), 7.62–7.59 (m, 2H). 13 C NMR (151 MHz, Chloroform-d 6 ) δ -0.1, 127.9, 129.6, 132.9, 139.0 ppm. HRMS m / z (ESI) calcd for C 8 H 12 OSi [M + H] + : 153.0736, found:153.0740.

[0089] The structure formula of the product is as follows:

[0090]

[0091] Example 7

[0092] Synthesis of 1,4-phenylenebis(dimethylsilanol)

[0093] According to the synthesis method described in Example 1, the difference is that the substrate used is 1,4-bis(dimethylsilyl)benzene (38.88 mg, 0.2 mmol), and 42.96 mg of the product is obtained, with a yield of 95%.

[0094] 1 H NMR (DMSO-d 6 ): δ0.24 (s, 12H), 5.89 (s, 2H), 7.53 (s, 4H). 13 C NMR (DMSO-d 6 ): δ1.0, 132.5, 141.7 ppm. HRMS m / z (ESI) calcd for C 10 H 18 O 2 Si 2 [M + H] + : 195.1385, found:195.1388.

[0095] The structural formula of the product is as follows:

[0096]

[0097] Example 8

[0098] Synthesis of tert-butyldiphenylsilanol

[0099] According to the synthesis method described in Example 1, the difference is that the substrate used is tert-butyldiphenylsilane (48.03 mg, 0.2 mmol), and 49.23 mg of the product is obtained, with a yield of 96%.

[0100] 1 H NMR (600 MHz, Chloroform-d 6 ) δ7.68 - 7.73 (m, 2H), 7.33 - 7.43 (m, 3H), 1.06 (s, 9H). 13 C NMR (151 MHz, Chloroform-d 6 ) 135.1, 134.7, 129.6, 127.7, 25.6, 19.0 ppm. HRMS m / z (ESI) calcd for C 16 H 20 OSi[M + H] + : 257.1362, found:257.1363.

[0101] The structural formula of the product is as follows:

[0102]

[0103] Example 9

[0104] Synthesis of methyldiphenylsilanol

[0105] According to the synthesis method described in Example 1, the difference is that the substrate used is diphenylmethylsilane (39.67 mg, 0.2 mmol), and 39.82 mg of the product is obtained with a yield of 93%.

[0106] 1 H NMR (600 MHz, Chloroform-d 6 ) δ 7.60 - 7.40 (m, 4H), 7.39 - 7.36 (m, 6H), 6.55 (br, 1H), 0.54 (s, 3H). 13 C NMR (151 MHz, Chloroform-d 6 ) δ = -1.1, 128.1, 130.0, 134.1, 137.2 ppm. HRMS m / z (ESI) calcd for C 13 H 14 OSi[M + H] + : 215.0892, found 215.0893.

[0107] The structural formula of the product is as follows:

[0108]

[0109] Example 10

[0110] Synthesis of tribenzylsilanol

[0111] According to the synthesis method described in Example 1, the difference is that the substrate used is tribenzylsilane (60.50 mg, 0.2 mmol), and 61.72 mg of the product is obtained with a yield of 97%.

[0112] 1 H NMR (600 MHz, Chloroform-d6) δ 7.22 - 7.08 (m, 6H), 7.06 - 7.01 (m, 9H), 6.05 (s, 1H), 2.02 (s, 6H). 13 C NMR (151 MHz, Chloroform-d6) δ 139.21, 129.00, 128.55, 124.50, 24.61 ppm. HRMS m / z (ESI) calcd for C 21 H 22 OSi[M + H]+: 319.1518, found: 319.1518.

[0113] The structural formula of the product is as follows:

[0114]

[0115] Example 11

[0116] Synthesis of dimethyl(p-tolyl)silanol

[0117] According to the synthesis method described in Example 1, the difference is that the substrate used is dimethyl(p-tolyl)silane (30.01 mg, 0.2 mmol), and 27.24 mg of the product is obtained, with a yield of 82%.

[0118] 1 H NMR (400 MHz, Chloroform-d): δ = 7.51 (d, J = 7.8 Hz, 2H), 7.23 (d, J = 7.7 Hz, 2H), 2.39 (s, 3H), 2.12 (br s, 1H), 0.41 (s, 6H). 13 C NMR (101 MHz, Chloroform-d): δ = 139.55, 135.51, 133.09, 128.68, 21.48, -0.01. HRMS m / z (ESI) calcd for C 9 H 18 OSi[M+H] + : 167.0892, found: 167.0894.

[0119] The structural formula of the product is as follows:

[0120]

[0121] Example 12

[0122] Synthesis of (4-fluorophenyl)dimethylsilanol

[0123] According to the synthesis method described in Example 1, the difference is that the substrate used is (4-fluorophenyl)dimethylsilane (31.81 mg, 0.2 mmol), and 30.60 mg of the product is obtained, with a yield of 90%.

[0124] 1 H NMR (400 MHz, Chloroform-d): δ = 7.51 (t, J = 7.1 Hz, 2H), 7.02 (t, J = 8.8 Hz, 2H), 2.56 (br s, 1H), 0.34 (s, 6H). 1313C NMR (101 MHz, Chloroform-d): δ = 165.20, 162.73, 135.11, 135.03, 115.07, 114.88, 0.03.; HRMS(ESI) calcd for C 8 H 11 FOSi [M+H] + : 171.0641, found: 171.0645.

[0125] The structural formula of the product is as follows:

[0126]

[0127] Example 13

[0128] Synthesis of (4-chlorophenyl)dimethylsilanol

[0129] According to the synthesis method described in Example 1, the difference is that the substrate used is (4-chlorophenyl)dimethylsilane (34.20 mg, 0.2 mmol), and 29.75 mg of the product is obtained with a yield of 80%.

[0130] 1 1H NMR (400 MHz, Chloroform-d): δ = 7.51 (d, J = 7.6 Hz, 2H), 7.35 (d, J = 7.6 Hz, 2H), 1.92 (br s, 1H), 0.39 (s, 3H). 13 13C NMR (101 MHz, Chloroform-d): δ = 137.26, 135.86, 134.42, 128.06, -0.07. HRMS(ESI) calcd for C 8 H 11 ClOSi [M+H] + : 187.0346, found: 187.0348.

[0131] The structural formula of the product is as follows:

[0132]

[0133] Example 14

[0134] Synthesis of (4-methoxyphenyl)dimethylsilanol

[0135] According to the synthesis method described in Example 1, the difference is that the substrate used is (4-methoxyphenyl)dimethylsilane (33.21 mg, 0.2 mmol), and 30.22 mg of the product is obtained with a yield of 83%.

[0136] 1 1H NMR (400 MHz, Chloroform-d): δ = 7.49 (d, J = 8.6 Hz, 2H), 6.90 (d, J = 8.6 Hz, 2H), 3.79 (s, 3H), 2.44 (br s, 1H), 0.34 (s, 6H). 13 13C NMR (101 MHz, Chloroform-d): δ = 160.71, 134.59, 130.19, 113.53, 54.98, 0.03. HRMS (ESI) cald for C 9 H 15 O 2 Si [M+H] + : 183.0841, found: 183.0841.

[0137] The structural formula of the product is as follows:

[0138]

[0139] Example 15

[0140] Synthesis of dimethyl(m-tolyl)silanol

[0141] According to the synthesis method described in Example 1, the difference is that the substrate used is dimethyl(m-phenylmethyl)silane (29.83 mg, 0.2 mmol), and 27.07 mg of the product is obtained, with a yield of 82%.

[0142] 1 1H NMR (400 MHz, Chloroform-d): δ = 7.39 (d, J = 10.7 Hz, 2H), 7.28 (t, J = 7.3 Hz, 1H), 7.21 (d, J = 7.5 Hz, 1H), 2.36 (s, 3H), 2.09 (br s, 1H), 0.39 (s, 6H). 13 13C NMR (101 MHz, Chloroform-d): δ = 138.95, 137.22, 133.66, 130.38, 130.02, 127.81, 21.44, -0.05. HRMS (ESI) calcd for C 9 H 14 OSi [M+H] + : 166.0814, found: 166.0816.

[0143] The structural formula of the product is as follows:

[0144]

[0145] Example 16

[0146] Synthesis of (2-Methoxyphenyl)dimethylsilanol

[0147] According to the synthesis method described in Example 1, the difference is that the substrate used is (2-methoxyphenyl)dimethylsilane (33.21 mg, 0.2 mmol), and 49.32 mg of the product is obtained, with a yield of 85%.

[0148] 1 H NMR (400 MHz, Chloroform-d): δ = 7.43 (d, J = 7.0 Hz, 1H), 7.39 (t, J = 7.9 Hz, 1H), 7.00 (t, J = 7.2 Hz, 1H), 6.87 (d, J = 8.2 Hz, 1H), 3.85 (s, 3H), 2.47 (br s, 1H), 0.40 (s, 6H). 13 C NMR (101 MHz, Chloroform-d): δ = 163.80, 134.51, 131.26, 126.83, 120.77, 109.58, 55.16, 0.27. HRMS (ESI) calcd for C 9 H 15 O 2 Si [M+H] + : 183.0841, found: 183.0840.

[0149] The structural formula of the product is as follows:

[0150]

[0151] Example 17

[0152] Synthesis of (3,5-Dimethylphenyl)dimethylsilanol

[0153] According to the synthesis method described in Example 1, the difference is that the substrate used is (3,5-dimethylphenyl)dimethylsilane (32.82 mg, 0.2 mmol), and 28.82 mg of the product is obtained, with a yield of 81%.

[0154] 1 H NMR (400 MHz, Chloroform-d): δ = 7.23 (s, 2H), 7.07 (s, 1H), 2.36 (s, 6H), 2.12 (br s, 1H), 0.41 (s, 6H). 1313C NMR (101 MHz, Chloroform-d): δ = 138.88, 137.22, 131.33, 130.71, 21.29, -0.01. HRMS (ESI) calcd for C 10 H 16 OSi [M+H] + : 181.1049, found: 181.1053.

[0155] The structural formula of the product is as follows:

[0156]

[0157] Example 18

[0158] Synthesis of (3-fluorophenyl)dimethylsilanol

[0159] According to the synthesis method described in Example 1, the difference is that the substrate used is (3-fluorophenyl)dimethylsilane (31.81 mg, 0.2 mmol), and 29.75 mg of the product is obtained, with a yield of 88%.

[0160] 1 1H NMR (400 MHz, Chloroform-d): δ = 7.46 - 7.33 (m, 2H), 7.28 (d, J = 8.5 Hz, 1H), 7.10 (t, J = 7.0 Hz, 1H), 2.51 (br s, 1H), 0.42 (s, 6H). 13 13C NMR (101 MHz, Chloroform-d): δ = 163.84, 161.37, 142.12, 134.43, 129.76, 129.69, 128.54, 128.51, 128.10, 119.48, 119.30, 116.59, 116.38, -0.12. HRMS (ESI) calcd for C 8 H 11 FOSi [M+H] + : 170.0563, found: 170.0566.

[0161] The structural formula of the product is as follows:

[0162]

[0163] In summary, the present invention effectively overcomes various disadvantages in the prior art and has high industrial utilization value.

[0164] The above embodiments are only illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A method for synthesizing silanols by polyoxometalate-catalyzed oxidation of silanes, characterized in that, a polyoxometalate catalyst, a hydrosilane represented by Formula I, an oxidant and an organic solvent are reacted and then filtered, the polyoxometalate catalyst is recovered, and the filtrate is separated and purified to obtain a silanol represented by Formula II: Among them, when R in Formula I 1 is H, R' in Formula II is OH; when R in Formula I 1 is selected from any one of C1-C4 alkyl, phenyl, substituted phenyl, benzyl, and substituted benzyl, R' in Formula II is the same as R in Formula I 1 ; R 2 independently selected from any one of C1-C4 alkyl, phenyl, substituted phenyl, benzyl, and substituted benzyl; R 3 independently selected from any one of C1-C4 alkyl, phenyl, substituted phenyl, benzyl, and substituted benzyl; the substituents in the substituted phenyl and substituted benzyl are any one of C1-C4 alkyl, C1-C4 alkoxy, halogen or hydrosilyl; the polyoxometalate catalyst is an Anderson-type polyoxometalate with Co as the central atom.

2. The method according to claim 1, characterized in that, the structural formula of the Anderson-type polyoxometalate with Co as the central atom is as shown in Formula III below:

3. The method according to claim 1, characterized in that, the organic solvent is selected from tetrahydrofuran.

4. The method according to claim 1, characterized in that, based on the Si-H bond in the hydrosilane, the dosage of the polyoxometalate catalyst is 4 mol% to 12 mol%.

5. The method according to claim 1, characterized in that, the dosage ratio of the organic solvent to the hydrosilane is (10-15) mL: 1 mmol.

6. The method according to claim 1, characterized in that, the oxidant is hydrogen peroxide, and the molar ratio of hydrogen peroxide to hydrosilane is 1.5-3:

1.

7. The method according to claim 1, characterized in that, includes any one of the following features: 1) The hydrosilane is selected from aromatic silanes, the reaction temperature is room temperature, and the reaction time is 5-8 h; 2) The hydrosilane is selected from alkyl silanes, the reaction temperature is 50-70 °C, and the reaction time is 18-30 h; 3) The polyoxometalate catalyst, the hydrosilane represented by Formula I, the oxidant and the organic solvent are placed in a reactor for reaction.

8. The method according to claim 1, characterized in that, the recovery of the polyoxometalate catalyst specifically includes that after the reaction system is cooled to room temperature, it is filtered, the filter residue is collected, and the filter residue can be reused after washing, centrifuging and drying.

9. The method according to claim 1, characterized in that, the separation and purification is column chromatography, the target product is collected, the solvent is removed to obtain silanol; preferably, the method for removing the solvent is vacuum distillation.

10. The method according to claim 9, characterized in that, the eluent for the column chromatography is a mixed solution of petroleum ether and ethyl acetate with a volume ratio of 50-100: 1.

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