Method for preparing alpha-alkenyl boric acid ester and polyboric acid ester compounds through martensite hydroboration and polyboronation of alkyne

Abstract

The invention discloses a method for preparing alpha-alkenyl boric acid ester and multi-boric acid ester compounds through martensite hydroboration and multi-boronation of alkyne. The method comprises the following steps: carrying out Markov hydroboration or multi-boronation reaction on a mixed reaction system containing an alkyne compound, a boronation reagent, an additive and a solvent to selectively prepare polyborate compounds such as alpha-alkenyl borate, 1, 2, 2-alkyl triborate, 1, 2-alkyl diborate or 2, 2-alkyl diborate; wherein the alkyne compound at least contains one carbon-carbon triple bond located at a terminal position, the boronizing reagent comprises bis (boric acid) ester, the additive comprises a proton source, and the solvent comprises an organic solvent. The method provided by the invention does not need to adopt a metal catalyst and a complex ligand, and is simple to operate, low in cost, good in selectivity and easy to amplify; and the substrate is wide in application range and has universality.

Description

Technical Field

[0001] The invention belongs to the technical field of organic synthesis, and particularly relates to a method for preparing alpha-alkenyl borate and polyborate compounds by Markovnikov hydroboration and polyboration of alkynes. Background Art

[0002] Boric acid ester compounds have stable structures and diverse transformation modes, and play a very important role in the synthesis of biomedicine, pesticides, functional materials, etc. The synthesis of boric acid ester compounds has always been an important topic in organic chemistry. For example, the classic Grignard reagent reacts with boric acid triesters to prepare alkyl or aryl borate esters. Compared with the classic method, the hydroboration and polyboration of alkynes have the advantages of easy availability of raw materials, high atom economy and rich product structures. However, reactions such as hydroboration or polyboration of alkynes have problems such as difficult control of selectivity.

[0003] For the synthesis of α-olefin borate esters, transition metal catalysis methods such as copper or cobalt are mainly used. For example, in 2011, Hoveyda et al. used divalent copper coordinated by nitrogen heterocyclic carbene (NHC) ligand as catalyst, B2pin2 as boron reagent, and methanol as proton source to report the first Markovnikov hydroboration of terminal alkynes to synthesize α-olefin borate esters. In 2021, Bertrand, Jazzar, Engle et al. used cyclic (alkyl) (amino) carbene (CAAC) instead of NHC as ligand, and also used B2pin2 and methanol as boron reagent and proton source to achieve copper-catalyzed Markovnikov hydroboration of terminal alkynes to synthesize α-olefin borate esters. In 2020 and 2021, the Gade group and the Lu group used different trinitrogen anion-coordinated cobalt complexes as catalysts and pinacol borane (HBpin) as boron reagent, respectively, to successively report cobalt-catalyzed Markovnikov hydroboration of terminal alkynes. Despite the above research results, the use of transition metal catalysts has brought many limitations. First, metal residues will affect the later application of drugs and materials; second, the complex and expensive ligands make the reaction unsuitable for large-scale industrialization.

[0004] Regarding the synthesis of alkyl polyborates, theoretically, polyboration of alkynes can generate three types of alkyl diborates (terminal geminal diborates, 1,2-alkyl diborates, and internal geminal diborates) and three types of alkyl triborates (1,1,1-alkyl triborates, 1,1,2-alkyl triborates, and 1,2,2-alkyl triborates). However, currently only two types of alkyl diborates (terminal geminal diborates and 1,2-alkyl diborates) and two types of alkyl triborates (1,1,1-alkyl triborates and 1,1,2-alkyl triborates) can be synthesized by polyboration of terminal alkynes. For example, in 2009, Shibata's group reported the first rhodium-catalyzed 1,1-alkyl diboration of terminal alkynes to prepare terminal geminal diborates. In 2016, Huang et al. achieved cobalt-catalyzed 1,1-alkyl diboration of terminal alkynes, further expanding the substrate application range of the reaction. In 2009, Hoveyda et al. reported a copper-catalyzed 1,2-diboration reaction of terminal alkynes to obtain 1,2-alkyl diborates. Subsequently, Song et al. achieved the synthesis of 1,2-alkyl diborates by cesium carbonate-promoted diboration of terminal alkynes and the synthesis of 1,1,2-alkyl triborates by potassium carbonate-promoted polyboration of terminal alkynes. In 2019, Marder's group reported a copper-catalyzed 1,1,1-triboration reaction to prepare 1,1,1-alkyl triborates. To date, 2,2-alkyl diborates and 1,2,2-alkyl triborates cannot be prepared by simple polyboration of terminal alkynes.

[0005] In summary, it is of great significance to develop metal-free Markovnikov hydroboration and polyboration of terminal alkynes to prepare α-olefin borate esters, as well as polyborate compounds such as 1,2-alkyl diborates, 2,2-alkyl diborates and 1,2,2-alkyl triborates. This will significantly promote the development of the synthesis of α-olefin borate esters and alkyl polyborates, and provide a strong basic guarantee for the development of drugs and functional materials. Summary of the invention

[0006] In order to solve all or part of the above technical problems, the main purpose of the present invention is to provide a method for preparing α-alkenyl borate by Markovnikov hydroboration of alkynes, and a method for preparing polyborate compounds by polyboration of alkynes, and further develop a new method for preparing 1,2-alkyl diborates, 2,2-alkyl diborates and 1,2,2-alkyl triborates by diboration and triboration reactions using terminal alkynes as raw materials, so as to overcome the shortcomings of the prior art.

[0007] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention includes:

[0008] A first aspect of the present invention provides a method for preparing α-alkenyl borate by Markovnigen hydroboration of alkynes, comprising: subjecting a first mixed reaction system containing an alkyne compound, a borating agent, an additive and a solvent to a Markovnigen hydroboration reaction; wherein the alkyne compound contains at least one carbon-carbon triple bond at a terminal position, the borating agent comprises a biborate, the additive comprises a proton source, and the solvent comprises an organic solvent.

[0009] The second aspect of the present invention provides a method for preparing polyborate compounds by polyboration of alkynes, which can produce polyborate compounds such as 1,2,2-alkyl triborates, 1,2-alkyl diborates or 2,2-alkyl diborates, comprising: subjecting a second mixed reaction system containing an alkyne compound, a borating agent, an additive and a solvent to a polyboration reaction; wherein the alkyne compound contains at least one carbon-carbon triple bond at a terminal position, the borating agent comprises a diborate, the additive comprises a proton source, and the solvent comprises an organic solvent.

[0010] Compared with the prior art, the present invention has at least the following beneficial effects:

[0011] 1) The method for preparing α-olefin borate and polyborate compounds provided by the present invention does not require the use of metal catalysts and complex ligands, has low reaction cost, is easy to operate, is easy to scale up, and has the potential for industrialization;

[0012] 2) The Markovnikov hydroboration method for terminal alkynes provided by the present invention has extremely high regioselectivity (can reach >99:1), is applicable to a variety of alkyne compounds, has a wide range of substrate applications, and provides a simple and efficient approach for the preparation of α-olefin borate esters;

[0013] 3) The present invention provides a method for synthesizing polyboric acid ester compounds, which realizes the polyboration of alkynes without metal participation, and in particular realizes the 1,2-diboration of aromatic terminal alkynes without metal participation, thus creating a novel and practical method for the synthesis of 1,2-alkyl diboric acid esters;

[0014] 4) The present invention realizes the 1,2,2-triboration and 2,2-diboration of terminal alkyne compounds for the first time. The substrate has a wide range of applicability, the process is simple, and it can be prepared on a large scale. It develops a novel method with industrial application prospects for the preparation of 1,2,2-alkyl triborates and 2,2-alkyl diborates. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1a is the hydrogen nuclear magnetic resonance spectrum of the α-alkenyl borate ester 3 obtained in Example 1 of the present invention;

[0017] Figure 1b is the carbon spectrum of α-alkenyl borate ester 3 obtained in Example 1 of the present invention;

[0018] Figure 2a is the hydrogen nuclear magnetic resonance spectrum of 1,2,2-alkyl triborate ester 5 obtained in Example 71 of the present invention;

[0019] Figure 2b is the carbon spectrum of 1,2,2-alkyl triborate 5 obtained in Example 71 of the present invention;

[0020] Figure 2c is the boron spectrum of 1,2,2-alkyl triborate 5 obtained in Example 71 of the present invention;

[0021] Figure 3a is the hydrogen nuclear magnetic resonance spectrum of 1,2-alkylbisborate ester 12 obtained in Example 88 of the present invention;

[0022] Figure 3b is the carbon spectrum of 1,2-alkylbisborate ester 12 obtained in Example 88 of the present invention;

[0023] Figure 4a is the hydrogen nuclear magnetic resonance spectrum of 2,2-alkylbisborate ester 14 obtained in Example 106 of the present invention;

[0024] Figure 4b is the carbon spectrum of 2,2-alkylbisborate ester 14 obtained in Example 106 of the present invention;

[0025] Figure 4c is the boron spectrum of 2,2-alkylbisborate ester 14 obtained in Example 106 of the present invention;

[0026] Figure 5 It is the gas chromatogram of α-alkenyl borate ester 3 obtained in Example 1 of the present invention.

[0027] Figure 6 This is the gas chromatogram of 1,2,2-alkyl triborate 5 obtained in Example 71 of the present invention.

[0028] Figure 7This is the gas chromatogram of 1,2-alkylbisborate ester 12 obtained in Example 88 of the present invention.

[0029] Figure 8 It is a gas chromatogram of 2,2-alkylbisborate ester 14 obtained in Example 106 of the present invention. DETAILED DESCRIPTION

[0030] In view of the deficiencies in the prior art, the inventors of this case proposed the technical concept of the present invention after long-term research. In the presence of biborates and proton source additives, metal-free Markovnikov hydroboration and 1,2-bisboration, 2,2-bisboration and 1,2,2-triboration of terminal alkynes are achieved, and α-olefin borate is efficiently synthesized in one step, as well as polyborate compounds such as 1,2-alkylbisborates, 2,2-alkylbisborates or 1,2,2-alkyltriborates are efficiently synthesized in one step.

[0031] The technical solution, its implementation process and principle will be further explained as follows.

[0032] As one aspect of the technical solution of the present invention, a method for preparing α-alkenyl borate by Markovnigen hydroboration of alkynes is provided, comprising: subjecting a first mixed reaction system containing an alkyne compound, a borating agent, an additive and a solvent to a Markovnigen hydroboration reaction; wherein the alkyne compound contains at least one carbon-carbon triple bond at a terminal position, the borating agent comprises a biborate, the additive comprises a proton source (the proton source is used to provide protons), and the solvent comprises an organic solvent.

[0033] In some embodiments, the biborate includes bis(bis(catechol) borate (B2cat2) and / or tetrahydroxydiboron (B2(OH)4).

[0034] In some preferred embodiments, the biboric acid ester includes bis(bis(catechol) borate), which has a higher yield.

[0035] In some embodiments, the organic solvent includes any one or a combination of two or more of N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), hexamethylphosphoric triamide, dimethyl sulfoxide, 1,4-dioxane, ethylene glycol dimethyl ether, toluene, 1,2-dichloroethane, acetonitrile, and methanol, but is not limited thereto.

[0036] In some preferred embodiments, the organic solvent includes N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and more preferably includes N,N-dimethylformamide.

[0037] In some embodiments, the proton source includes one or a combination of water, alcohol compounds, carboxylic acid compounds, amide compounds, phenylboronic acid compounds (referring to phenylboronic acid and its derivatives), and phenolic compounds.

[0038] In some embodiments, the alcohol compound includes one or a combination of more of methanol, ethanol, n-propanol, isopropanol, tert-butanol, trifluoroethanol, and pinacol, but is not limited thereto.

[0039] In some embodiments, the carboxylic acid compound includes benzoic acid, but is not limited thereto.

[0040] In some embodiments, the amide compound includes p-toluamide, but is not limited thereto.

[0041] In some embodiments, the phenylboronic acid compound includes phenylboric acid, but is not limited thereto.

[0042] In some embodiments, the phenolic compound includes one or a combination of more of phenol, p-cyanophenol, p-methoxyphenol, p-diphenol, m-diphenol, o-diphenol, and 2,6-di-tert-butyl-4-methylphenol, but is not limited thereto.

[0043] In some preferred embodiments, the proton source includes a phenolic compound, that is, the method for preparing α-alkenyl borate by Markovnikov hydroboration of terminal alkynes without metal participation includes a protic additive of a phenolic compound, and a boronating agent and an alkyne compound undergo a Markovnikov hydroboration reaction in an organic solvent to obtain an α-alkenyl borate. On the one hand, the acidity (pH value) of the phenolic compound is suitable for activating alkynes; on the other hand, the phenol oxide anion generated after the phenolic compound provides protons is not easy to act as a strong base to activate the biborate, thereby preventing the occurrence of side reactions.

[0044] The method preferably uses one or more of N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone as organic solvents and a phenolic compound as a proton source to prepare α-olefin borate esters.

[0045] In some embodiments, the alkyne compound comprises C 4-22 Alkyl alkynes, C 8-20 The method provided by the present invention has a wide range of substrate applications and is suitable for a variety of terminal alkyne compounds.

[0046] In some embodiments, the first mixed reaction system does not contain a metal-containing catalyst, that is, the method provided by the present invention can prepare α-olefin borate esters without using a metal catalyst.

[0047] In some embodiments, the temperature of the Markovnikov hydroboration reaction is 25-100°C.

[0048] In some embodiments, the Markovnikov hydroboration reaction time is 6 to 36 hours.

[0049] In some embodiments, the molar ratio of the biboric acid ester to the alkyne compound is 1-3:1. In other words, the amount of biboric acid ester used is 1-3 equivalents of the molar amount of the alkyne compound.

[0050] In some embodiments, the molar ratio of the proton source to the alkyne compound is 1-5:1. In other words, the amount of the protic additive is 1-5 equivalents of the molar amount of the alkyne compound.

[0051] In some embodiments, the amount of the organic solvent used is such that the total molar concentration of the alkyne compound, the boronating agent, and the additive is 0.2 to 3.5 mol / L.

[0052] In some embodiments, the method further comprises: after the Markovnikov hydroboration reaction is completed, adding pinacol to the product obtained by the reaction to obtain an α-alkenyl borate.

[0053] In some embodiments, the method specifically includes: adding a triethylamine solution of pinacol with a concentration of 1.4 to 2.3 mol / L to the product obtained by the reaction, wherein the amount of pinacol added is 5 to 8 equivalents of the molar amount of the alkyne compound.

[0054] Another aspect of the present invention further provides an α-alkenyl borate ester, which is prepared by the method for preparing α-alkenyl borate ester by Markovnikov hydroboration of alkynes described in any technical solution.

[0055] As another aspect of the technical solution of the present invention, a method for preparing polyborate compounds by polyboration of alkynes is provided, comprising: subjecting a second mixed reaction system containing an alkyne compound, a borating agent, an additive and a solvent to a polyboration reaction to obtain a polyborate compound; wherein the alkyne compound contains at least one carbon-carbon triple bond at a terminal position, the borating agent comprises a diborate, the additive comprises a proton source, and the solvent comprises an organic solvent.

[0056] In some embodiments, the borate ester includes bis(bis(catechol) borate (B2cat2) and / or tetra(hydroxy)diboron (B2(OH)4).

[0057] In some preferred embodiments, the biboric acid ester includes bis(bis(catechol) borate (B2cat2), which has a higher yield.

[0058] In some embodiments, the organic solvent includes any one or a combination of two or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, hexamethylphosphoric triamide, dimethyl sulfoxide, 1,4-dioxane, ethylene glycol dimethyl ether, toluene, 1,2-dichloroethane, acetonitrile, and methanol, but is not limited thereto.

[0059] In some preferred embodiments, the organic solvent includes one or a combination of N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone.

[0060] In some embodiments, the proton source includes one or a combination of water, alcohol compounds, carboxylic acid compounds, sulfonic acid compounds, phenylboronic acid compounds (referring to phenylboronic acid and its derivatives), and phenolic compounds.

[0061] In some embodiments, the alcohol compound includes one or a combination of more of methanol, ethanol, n-propanol, isopropanol, tert-butanol, and hexafluoroisopropanol, but is not limited thereto.

[0062] In some embodiments, the carboxylic acid compound includes one or a combination of more of benzoic acid, tris-benzoic acid, p-dibenzoic acid, acetic acid, and trifluoroacetic acid, but is not limited thereto.

[0063] In some embodiments, the sulfonic acid compound includes one or a combination of methanesulfonic acid and p-toluenesulfonic acid, but is not limited thereto.

[0064] In some embodiments, the boric acid compound includes phenylboric acid, but is not limited thereto.

[0065] In some embodiments, the phenolic compound includes one or a combination of p-cyanophenol, p-methoxyphenol, p-diphenol, m-diphenol, o-diphenol, and 2,6-di-tert-butyl-4-methylphenol, but is not limited thereto.

[0066] In some preferred embodiments, the proton source includes water and / or a carboxylic acid compound, that is, the method for preparing polyboron compounds such as 1,2,2-alkyl triborates, 1,2-alkyl bisborates or 2,2-alkyl bisborates by metal-free polyboration of terminal alkynes uses an additive including water and / or a carboxylic acid compound as a proton source.

[0067] In the embodiment where the desired product is 1,2,2-alkyl triborates or 1,2-alkyl diborates, the proton source preferably includes water. The hydroxide anions generated by water providing protons can act as a strong base to activate the biborates, promoting further diboration of the double bonds of the α-alkenyl borate to generate 1,2,2-alkyl triborates or 1,2-alkyl diborates.

[0068] In the embodiment where the desired product is 2,2-alkylbisboronate, the proton source preferably includes a carboxylic acid compound. Carboxylic acid can more easily activate the carbon-carbon double bond in α-alkenylboronate, causing it to undergo Markovnikov-type hydroboration again to generate 2,2-alkylbisboronate.

[0069] The method preferably uses one or more of N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone as organic solvents, and uses water or carboxylic acid compounds as proton sources to prepare polyboron compounds.

[0070] In some embodiments, the alkyne compound comprises C 4-22 Alkyl alkynes, C 8-20 One or more combinations of aryl alkynes, but not limited thereto.

[0071] In some embodiments, the temperature of the polyboration reaction is 60-100°C.

[0072] In some embodiments, the polyboration reaction time is 12N36 hours.

[0073] In some embodiments, the molar ratio of the biboric acid ester to the alkyne compound is 1-3:1.

[0074] In some embodiments, the molar ratio of the proton source to the alkyne compound is 1-5:1.

[0075] In some embodiments, the amount of the organic solvent used is such that the total molar concentration of the alkyne compound, the boronating agent, and the additive is 0.2N3.5 mol / L.

[0076] In some embodiments, the method further comprises: after the polyboration reaction is completed, adding pinacol to the product obtained by the reaction to obtain a polyboric ester compound.

[0077] In some embodiments, the method specifically includes: adding a triethylamine solution of pinacol with a concentration of 1.4 to 2.3 mol / L to the product obtained by the reaction, wherein the amount of pinacol added is 5 to 8 equivalents of the molar amount of the alkyne compound.

[0078] Another aspect of the present invention further provides a polyborate compound, which is prepared by the method for preparing polyborate compounds by polyboration of alkynes described in any one of the technical solutions.

[0079] In some embodiments, the polyboric acid ester compound is 1,2,2-alkyl triboric acid ester, 1,2-alkyl bisboric acid ester or 2,2-alkyl bisboric acid ester.

[0080] By means of the above technical scheme, the raw materials, boronating reagents and protic additives used in the present invention are cheap and readily available, the reaction conditions are mild, the operation is simple, and no metal residues are left after the reaction. α-Alkenyl borate can be prepared with a Markovnikov selectivity of up to >99:1 and a separation yield of 92%, and polyboron compounds such as 1,2,2-alkyl triborates, 1,2-alkyl diborates or 2,2-alkyl diborates can be prepared with a separation yield of up to 92%. Moreover, the method of the present invention has a wide range of substrate applicability, and is applicable to alkyl or aryl terminal alkynes containing various functional groups, and can realize large-scale preparation of polyboron compounds, has low requirements on equipment, and has the potential for industrialization.

[0081] The technical solution of the present invention is described in detail below in conjunction with specific embodiments so that those skilled in the art can better understand and implement the technical solution of the present invention. The specific functional details disclosed herein should not be interpreted as limiting, but only as the basis for the claims and as a representative basis for teaching those skilled in the art to adopt the present invention in different ways in any appropriate detailed embodiment.

[0082] Unless otherwise specified, the experimental materials used in the following examples can be purchased from conventional biochemical reagent companies.

[0083] Example 1

[0084] This embodiment provides a method for synthesizing α-olefin borate esters by Markovnikov hydroboration of terminal alkynes without metal participation, and the reaction process is as follows:

[0085]

[0086] Bis(2-hydroxy-1-pyrocatechol) borate B2cat2 (142.7 mg, 0.6 mmol), p-diphenol (66.0 mg, 0.6 mmol), phenylacetylene (20.4 mg, 0.2 mmol) and DMF (5 mL) were placed in a 25 mL reaction tube; the reaction tube was sealed and placed in an oil bath at 70°C for reaction for 12 hours. After the reaction, a solution of pinacol (190 mg, 1.6 mmol) in triethylamine (0.7 mL) was added, and the mixture was stirred at room temperature for 2 hours. The obtained reaction solution was concentrated and separated by column chromatography (using a silica gel column; eluent: petroleum ether / ethyl acetate = 30 / 1) to obtain a pure product α-alkenyl borate ester 3, which was a colorless liquid with an isolation yield of 72%.

[0087] The hydrogen and carbon NMR spectra of the α-alkenyl borate ester 3 obtained in this example are as follows: Figure 1a and Figure 1b shown. Figure 5 is a gas chromatogram of α-alkenyl borate ester 3 prepared in this example.

[0088] Embodiments 2 to 24

[0089]

[0090] B2cat2 (95.1 mg, 0.4 mmol), additive (0.2 mmol), phenylacetylene (20.4 mg, 0.2 mmol) and solvent (0.4 mL) were placed in a 25 mL reaction tube; the reaction tube was sealed and placed in an oil bath at 70°C for 12 hours, and after the reaction, a triethylamine (0.7 mL) solution of pinacol (190 mg, 1.6 mmol) was added and stirred at room temperature for 2 hours to obtain α-olefin borate ester 3. The reaction solution was quantified by GC using the internal standard method, with n-dodecane as the internal standard.

[0091] The additives, solvents, and yields of α-alkenyl borate esters 3 used in Examples 2-24 are shown in Table 1.

[0092] Table 1 Specific reaction conditions corresponding to Examples 2-24 and yields of α-olefin borate ester 3

[0093]

[0094] Embodiment 25

[0095]

[0096] B2cat2 (95.1 mg, 0.4 mmol), p-diphenol (22.0 mg, 0.2 mm mmol), phenylacetylene (20.4 mg, 0.2 mm mmol) and DMF (2 mL) were placed in a 25 mL reaction tube; the reaction tube was sealed and placed in an oil bath at 70°C for reaction for 12 hours, and then a triethylamine (0.7 mL) solution of pinacol (190 mg, 1.6 mmol) was added and stirred at room temperature for 2 hours to obtain α-olefin borate ester 3. The reaction solution was quantified by GC using the internal standard method, with n-dodecane as the internal standard, and the yield of α-olefin borate ester 3 was 62%.

[0097] Embodiment 26

[0098]

[0099] B2cat2 (118.9 mg, 0.5 mmol), p-diphenol (66.0 mg, 0.6 mmol), phenylacetylene (20.4 mg, 0.2 mmol) and DMF (5 mL) were placed in a 25 mL reaction tube; the reaction tube was sealed and placed in an oil bath at 70° C. for reaction for 12 hours, and then a triethylamine (0.7 mL) solution of pinacol (190 mg, 1.6 mmol) was added and stirred at room temperature for 2 hours to obtain α-olefin borate ester 3. The reaction solution was quantified by GC using the internal standard method, with n-dodecane as the internal standard, and the yield of α-olefin borate ester 3 was 72%.

[0100] Embodiment 27

[0101]

[0102] B2cat2 (142.7 mg, 0.6 mmol), p-diphenol (66.0 mg, 0.6 mmol), phenylacetylene (20.4 mg, 0.2 mmol) and DMF (5 mL) were placed in a 25 mL reaction tube; the reaction tube was sealed and placed in an oil bath at 25° C. for reaction for 12 hours, and then a triethylamine (0.7 mL) solution of pinacol (190 mg, 1.6 mmol) was added and stirred at room temperature for 2 hours to obtain α-olefin borate ester 3. The reaction solution was quantified by GC using the internal standard method, with n-dodecane as the internal standard, and the yield of α-olefin borate ester 3 was 9%.

[0103] Embodiment 28

[0104]

[0105] B2cat2 (142.7 mg, 0.6 mmol), p-diphenol (66.0 mg, 0.6 mmol), phenylacetylene (20.4 mg, 0.2 mmol) and DMF (5 mL) were placed in a 25 mL reaction tube; the reaction tube was sealed and placed in an oil bath at 50° C. for reaction for 12 hours, and then a triethylamine (0.7 mL) solution of pinacol (190 mg, 1.6 mmol) was added and stirred at room temperature for 2 hours to obtain α-olefin borate ester 3. The reaction solution was quantified by GC using the internal standard method, with n-dodecane as the internal standard, and the yield of α-olefin borate ester 3 was 42%.

[0106] Embodiment 29

[0107]

[0108] B2cat2 (142.7 mg, 0.6 mmol), p-diphenol (66.0 mg, 0.6 mmol), phenylacetylene (20.4 mg, 0.2 mmol) and DMF (5 mL) were placed in a 25 mL reaction tube; the reaction tube was sealed and placed in an oil bath at 90° C. for reaction for 12 hours, and then a triethylamine (0.7 mL) solution of pinacol (190 mg, 1.6 mmol) was added and stirred at room temperature for 2 hours to obtain α-olefin borate ester 3. The reaction solution was quantified by GC using the internal standard method, with n-dodecane as the internal standard, and the yield of α-olefin borate ester 3 was 69%.

[0109] Embodiment 30

[0110]

[0111] B2cat2 (142.7 mg, 0.6 mmol), p-diphenol (66.0 mg, 0.6 mmol), phenylacetylene (20.4 mg, 0.2 mmol) and DMF (5 mL) were placed in a 25 mL reaction tube; the reaction tube was sealed and placed in an oil bath at 100° C. for reaction for 12 hours, and then a triethylamine (0.7 mL) solution of pinacol (190 mg, 1.6 mmol) was added and stirred at room temperature for 2 hours to obtain α-olefin borate ester 3. The reaction solution was quantified by GC using the internal standard method, with n-dodecane as the internal standard, and the yield of α-olefin borate ester 3 was 14%.

[0112] Embodiment 31

[0113]

[0114] B2(OH)4 (53.8 mg, 0.6 mmol), p-diphenol (66.0 mg, 0.6 mmol), phenylacetylene (20.4 mg, 0.2 mmol) and DMF (5 mL) were placed in a 25 mL reaction tube; the reaction tube was sealed and placed in an oil bath at 70°C for reaction for 12 hours, and then a triethylamine (0.7 mL) solution of pinacol (190 mg, 1.6 mmol) was added and stirred at room temperature for 2 hours to obtain α-olefin borate ester 3. The reaction solution was quantified by GC using the internal standard method, with n-dodecane as the internal standard, and the yield of α-olefin borate ester 3 was 7%.

[0115] Embodiments 32 to 59

[0116] The operations and steps of Examples 32-59 are the same as those of Example 1, except that the type of terminal alkyne (i.e., substrate) is changed. Other conditions are the same. The specific yields of the obtained α-olefin borate compounds are shown in Table 2.

[0117] Table 2 Specific yields of α-olefin borate compounds in Examples 32-59

[0118]

[0119]

[0120]

[0121] Embodiment 60

[0122]

[0123] B2cat2 (142.7 mg, 0.6 mmol), p-diphenol (66.0 mg, 0.6 mmol), 1-octyne (22.0 mg, 0.2 mmol) and DMF (5 mL) were placed in a 25 mL reaction tube; the reaction tube was sealed and placed in an oil bath at 70°C for reaction for 12 hours, and then a triethylamine (0.7 mL) solution of pinacol (190 mg, 1.6 mmol) was added and stirred at room temperature for 2 hours to obtain 1,2,2-alkyl triborate 5. The reaction solution was quantified by GC using the internal standard method, with n-dodecane as the internal standard, and the yield of 1,2,2-alkyl triborate 5 was 9%.

[0124] Embodiment 61

[0125]

[0126] B2cat2 (142.7 mg, 0.6 mmol), p-diphenol (66.0 mg, 0.6 mmol), 1-octyne (22.0 mg, 0.2 mmol) and DMF (1 mL) were placed in a 25 mL reaction tube; the reaction tube was sealed and placed in an oil bath at 70°C for 12 hours, and then a triethylamine (0.7 mL) solution of pinacol (190 mg, 1.6 mmol) was added and stirred at room temperature for 2 hours to obtain 1,2,2-triborate 5. The reaction solution was quantified by GC using the internal standard method, with n-dodecane as the internal standard, and the yield of 1,2,2-alkyl triborate 5 was 22%.

[0127] Embodiment 62

[0128]

[0129] B2cat2 (142.7 mg, 0.6 mmol), p-diphenol (66.0 mg, 0.6 mmol), 1-octyne (22.0 mg, 0.2 mmol) and DMF (0.2 mL) were placed in a 25 mL reaction tube; the reaction tube was sealed and placed in an oil bath at 70°C for reaction for 12 hours, and then a triethylamine (0.7 mL) solution of pinacol (190 mg, 1.6 mmol) was added and stirred at room temperature for 2 hours to obtain 1,2,2-alkyl triborate 5. The reaction solution was quantified by GC using the internal standard method, with n-dodecane as the internal standard, and the yield of 1,2,2-alkyl triborate 5 was 44%.

[0130] Embodiment 63

[0131]

[0132] B2cat2 (142.7 mg, 0.6 mmol), p-diphenol (66.0 mg, 0.6 mmol), 1-octyne (22.0 mg, 0.2 mmol) and DMF (0.2 mL) were placed in a 25 mL reaction tube; the reaction tube was sealed and placed in an oil bath at 80°C for reaction for 12 hours, and then a triethylamine (0.7 mL) solution of pinacol (190 mg, 1.6 mmol) was added and stirred at room temperature for 2 hours to obtain 1,2,2-alkyl triborate 5. The reaction solution was quantified by GC using the internal standard method, with n-dodecane as the internal standard, and the yield of 1,2,2-alkyl triborate 5 was 50%.

[0133] Embodiment 64

[0134]

[0135] B2cat2 (142.7 mg, 0.6 mmol), p-diphenol (66.0 mg, 0.6 mmol), 1-octyne (22.0 mg, 0.2 mmol) and DMF (0.2 mL) were placed in a 25 mL reaction tube; the reaction tube was sealed and placed in an oil bath at 60°C for reaction for 12 hours, and then a triethylamine (0.7 mL) solution of pinacol (190 mg, 1.6 mmol) was added and stirred at room temperature for 2 hours to obtain 1,2,2-alkyl triborate 5. The reaction solution was quantified by GC using the internal standard method, with n-dodecane as the internal standard, and the yield of 1,2,2-alkyl triborate 5 was 19%.

[0136] Embodiment 65

[0137]

[0138] B2cat2 (142.7 mg, 0.6 mmol), p-diphenol (66.0 mg, 0.6 mmol), 1-octyne (22.0 mg, 0.2 mmol) and DMF (0.2 mL) were placed in a 25 mL reaction tube; the reaction tube was sealed and placed in an oil bath at 100°C for reaction for 12 hours, and then a triethylamine (0.7 mL) solution of pinacol (190 mg, 1.6 mmol) was added and stirred at room temperature for 2 hours to obtain 1,2,2-alkyl triborate 5. The reaction solution was quantified by GC using the internal standard method, with n-dodecane as the internal standard, and the yield of 1,2,2-alkyl triborate 5 was 21%.

[0139] Examples 66-69

[0140]

[0141] B2cat2 (142.7 mg, 0.6 mmol), additive (0.6 mmol), 1-octyne (22.0 mg, 0.2 mmol) and DMF (0.2 mL) were placed in a 25 mL reaction tube; the reaction tube was sealed and placed in an oil bath at 80°C for 12 hours, and then a triethylamine (0.7 mL) solution of pinacol (190 mg, 1.6 mmol) was added and stirred at room temperature for 2 hours to obtain 1,2,2-alkyl triborate 5. The reaction solution was quantified by GC using the internal standard method, with n-dodecane as the internal standard.

[0142] Table 3 shows the specific reaction conditions corresponding to Examples 66-69 and the yield of 1,2,2-alkyl triborate 5.

[0143] Table 3 Specific reaction conditions corresponding to Examples 66-69 and yields of 1,2,2-alkyl triborates 5

[0144] Group additive 1,2,2-Alkyl triborates 5 yield Embodiment 66 Ethanol 10％ Embodiment 67 Tert-Butanol 18％ Embodiment 68 Acetic acid 41％ Embodiment 69 water 62％

[0145] Embodiment 70

[0146]

[0147] B2(OH)4 (53.8 mg, 0.6 mmol), water (3.6 mg, 0.2 mmol), 1-octyne (22.0 mg, 0.2 mmol) and DMF (0.2 mL) were placed in a 25 mL reaction tube; the reaction tube was sealed and placed in an oil bath at 80°C for reaction for 12 hours, and then a triethylamine (0.7 mL) solution of pinacol (190 mg, 1.6 mmol) was added and stirred at room temperature for 2 hours to obtain 1,2,2-alkyl triborate 5. The reaction solution was quantified by GC using the internal standard method, with n-dodecane as the internal standard, and the yield of 1,2,2-alkyl triborate 5 was 12%.

[0148] Embodiment 71

[0149] This embodiment provides a method for synthesizing 1,2,2-alkyl triborates by 1,2,2-triboration of terminal alkynes without metal participation, and the reaction process is as follows:

[0150]

[0151] B2cat2 (142.7 mg, 0.6 mmol), water (3.6 mg, 0.2 mmol), 1-octyne (22.0 mg, 0.2 mmol) and DMAc (0.2 mL) were placed in a 25 mL reaction tube; the reaction tube was sealed and placed in an oil bath at 80° C. for reaction for 12 hours, and then a solution of pinacol (190 mg, 1.6 mmol) in triethylamine (0.7 mL) was added and stirred at room temperature for 2 hours; after the reaction, the reaction solution was concentrated and separated by column chromatography (using a silica gel column; eluent: petroleum ether / ether = 50 / 1) to obtain a pure product 1,2,2-alkyl triborate 5 as a white solid with an isolation yield of 66%.

[0152] Figure 2a , Figure 2b and Figure 2c They are respectively the hydrogen, carbon and boron nuclear magnetic resonance spectra of the 1,2,2-alkyl triborate ester 5 obtained in Example 71; Figure 6 This is a gas chromatogram of 1,2,2-alkyl triborate 5 obtained in Example 70.

[0153] Embodiment 72

[0154]

[0155] B2(OH)4 (53.8 mg, 0.6 mmol), p-diphenol (66.0 mg, 0.6 mmol), 1-octyne (22.0 mg, 0.2 mmol) and DMAc (0.2 mL) were placed in a 25 mL reaction tube; the reaction tube was sealed and placed in an oil bath at 80°C for 12 hours, and then a triethylamine (0.7 mL) solution of pinacol (190 mg, 1.6 mmol) was added and stirred at room temperature for 2 hours to obtain 1,2,2-alkyl triborate 5. The reaction solution was quantified by GC using the internal standard method, with n-dodecane as the internal standard, and the yield of 1,2,2-alkyl triborate 5 was 30%.

[0156] Embodiments 73 to 84

[0157] The operations and steps of Examples 73-84 are the same as those of Example 71, except that the type of terminal alkyne (i.e., substrate) is changed. Other conditions are the same. The specific yields of the obtained 1,2,2-alkyl triborate compounds are shown in Table 4.

[0158] Table 4 Specific yields of 1,2,2-alkyl triborates in Examples 72-83

[0159]

[0160]

[0161] Embodiment 85

[0162]

[0163] B2cat2 (142.7 mg, 0.6 mmol), water (3.6 mg, 0.2 mmol), terminal alkyne substrate 6 (57.3 mg, 0.2 mmol) and DMAc (0.2 mL) were placed in a 25 mL reaction tube; the reaction tube was sealed and placed in an oil bath at 80°C for 12 hours; then a triethylamine (0.7 mL) solution of pinacol (190 mg, 1.6 mmol) was added and stirred at room temperature for 2 hours. After the reaction was completed, the reaction solution was concentrated and separated by column chromatography (using a silica gel column; eluent: petroleum ether / ether = 10 / 1) to obtain a pure product 1,2,2-alkyl triborate 7, the product was a white solid, and the separation yield was 62%.

[0164] Embodiment 86

[0165]

[0166] B2cat2 (142.7 mg, 0.6 mmol), water (3.6 mg, 0.2 mmol), terminal alkyne substrate 8 (52.9 mg, 0.2 mmol) and DMAc (0.2 mL) were placed in a 25 mL reaction tube; the reaction tube was sealed and placed in an oil bath at 80°C for 12 hours; then a triethylamine (0.7 mL) solution of pinacol (190 mg, 1.6 mmol) was added and stirred at room temperature for 2 hours. After the reaction was completed, the reaction solution was concentrated and separated by column chromatography (using a silica gel column; eluent: petroleum ether / ether = 10 / 1) to obtain a pure product 1,2,2-alkyl triborate ester 9, the product being a white solid, with an isolated yield of 61%.

[0167] Embodiment 87

[0168]

[0169] B2cat2 (142.7 mg, 0.6 mmol), water (3.6 mg, 0.2 mmol), terminal alkyne substrate 10 (79.3 mg, 0.2 mmol) and DMAc (0.2 mL) were placed in a 25 mL reaction tube; the reaction tube was sealed and placed in an oil bath at 80°C for 12 hours; then a triethylamine (0.7 mL) solution of pinacol (190 mg, 1.6 mmol) was added and stirred at room temperature for 2 hours. After the reaction was completed, the reaction solution was concentrated and separated by column chromatography (using a silica gel column; eluent: petroleum ether / ether = 3 / 1) to obtain a pure product 1,2,2-alkyl triborate ester 11, the product was a white solid, and the separation yield was 46%.

[0170] Embodiment 88

[0171] This embodiment provides a method for synthesizing 1,2-alkyl diborates by 1,2-diboration of terminal alkynes without metal participation, and the reaction process is as follows:

[0172]

[0173] B2cat2 (118.9 mg, 0.5 mmol), water (3.6 mg, 0.2 mmol), terminal alkyne substrate 1 (20.4 mg, 0.2 mmol) and DMAc (0.2 mL) were placed in a 25 mL reaction tube; the reaction tube was sealed and placed in an oil bath at 80°C for 12 hours; then a triethylamine (0.7 mL) solution of pinacol (190 mg, 1.6 mmol) was added and stirred at room temperature for 2 hours. After the reaction was completed, the reaction solution was concentrated and separated by column chromatography (using a silica gel column; eluent: petroleum ether / ethyl acetate = 30 / 1) to obtain a pure product 1,2-alkylbisborate ester 12, which was a colorless liquid with an isolation yield of 86%.

[0174] Figure 3a and Figure 3b They are respectively the hydrogen and carbon nuclear magnetic resonance spectra of the 1,2-alkylbisboronic acid ester 12 obtained in Example 88; Figure 7 This is the gas chromatogram of 1,2-alkylbisborate ester 12 obtained in Example 87.

[0175] Embodiments 89 to 105

[0176] The operations and steps of Examples 89-105 are the same as those of Example 88, except that the type of terminal alkyne (i.e., substrate) is changed. Other conditions are the same. The specific yields of the obtained 1,2-alkyl diboronic acid ester compounds are shown in Table 5.

[0177] Table 5 Specific yields of 1,2-alkylbisboronic acid ester compounds in Examples 88-104

[0178]

[0179]

[0180]

[0181] Embodiment 106

[0182] This embodiment provides a method for synthesizing 2,2-alkyl diborates by 2,2-diboration of terminal alkynes without metal participation, and the reaction process is as follows:

[0183]

[0184] B2cat2 (142.7 mg, 0.6 mmol), tris(2-benzoic acid) (84.0 mg, 0.4 mmol), terminal alkyne substrate 13 (16.4 mg, 0.2 mmol) and DMF (0.5 mL) were placed in a 25 mL reaction tube; the reaction tube was sealed and placed in an oil bath at 70°C for 12 hours. Then a solution of pinacol (190 mg, 1.6 mmol) in triethylamine (0.7 mL) was added and stirred at room temperature for 2 hours. The reaction solution was concentrated and separated by column chromatography (using a silica gel column; eluent: petroleum ether / ethyl acetate = 20 / 1) to obtain a pure product 2,2-alkylbisborate ester 14, which was a colorless liquid with an isolated yield of 65%.

[0185] Figure 4a , Figure 4b and Figure 4c They are respectively the hydrogen, carbon and boron nuclear magnetic resonance spectra of the 2,2-alkylbisboronic acid ester 14 obtained in Example 106; Figure 8 This is a gas chromatogram of 2,2-alkylbisborate ester 14 obtained in Example 106.

[0186] Embodiment 107

[0187]

[0188] B2(OH)4 (53.8 mg, 0.6 mmol), tris(2-benzoic acid) (84.0 mg, 0.4 mmol), terminal alkyne substrate 13 (16.4 mg, 0.2 mmol) and DMF (0.5 mL) were placed in a 25 mL reaction tube; the reaction tube was sealed and placed in an oil bath at 70°C for 12 hours, and then a triethylamine (0.7 mL) solution of pinacol (190 mg, 1.6 mmol) was added and stirred at room temperature for 2 hours to obtain 2,2-alkylbisborate 14. The reaction solution was quantified by GC using the internal standard method, with n-dodecane as the internal standard, and the yield of 2,2-alkylbisborate 14 was 5%.

[0189] Embodiments 108 to 120

[0190] The operations and steps of Examples 108-120 are the same as those of Example 106, except that the types of additives and the types and amounts of solvents are changed. Other conditions are the same. The specific yields of the obtained 2,2-alkylbisboronic acid esters 14 are shown in Table 6.

[0191] Table 6 Yield of 2,2-alkylbisboronic acid ester 14 in Examples 108-120

[0192]

[0193] Embodiments 121 to 127

[0194] The operations and steps of Examples 121-127 are the same as those of Example 106, except that the type of terminal alkyne (i.e., substrate) is changed. Other conditions are the same. The specific yields of the obtained 2,2-alkylbisboronic acid ester compounds are shown in Table 7.

[0195] Table 7 Specific yields of 2,2-alkylbisboronic acid ester compounds in Examples 119-125

[0196]

[0197]

[0198] Embodiment 128

[0199]

[0200] B2cat2 (142.7 mg, 0.6 mmol), tribenzoic acid (84.0 mg, 0.4 mmol), terminal alkyne substrate 15 (16.4 mg, 0.2 mmol) and DMF (0.5 mL) were placed in a 25 mL reaction tube; the reaction tube was sealed and placed in an oil bath at 70°C for reaction for 12 hours. After the reaction, a solution of pinacol (190 mg, 1.6 mmol) in triethylamine (0.7 mL) was added and stirred at room temperature for 2 hours. The reaction solution was concentrated and separated by column chromatography (using a silica gel column; eluent: petroleum ether / ethyl acetate = 40 / 1) to obtain a pure product 2,2-alkylbisborate ester 16 as a colorless liquid with an isolation yield of 20%.

[0201] Comparative Example 1

[0202] The difference between Comparative Example 1 and Example 1 is that the bis(bis(di-ortho-catechol) borate in Example 1 is replaced by an equimolar amount of biboric acid pinacol ester (B2pin2), and the other steps are the same as Example 1. It is found that α-alkenyl borate cannot be synthesized, that is, the yield of α-alkenyl borate is 0%.

[0203] Comparative Example 2

[0204] The difference between Comparative Example 2 and Example 1 is that the bis(bis(bis(dipyrocatechol)) borate in Example 1 is replaced by an equimolar amount of pinacol borane (HBpin), and the other steps are the same as Example 1. It is found that α-alkenyl borate cannot be synthesized, that is, the yield of α-alkenyl borate is 0%.

[0205] Comparative Example 3

[0206] The difference between Comparative Example 3 and Example 1 is that the bis(bis(bis-catechol) borate in Example 1 is replaced by an equimolar amount of catechol borane (HBcat), and the rest is the same as Example 1. It is found that α-alkenyl borate cannot be synthesized, that is, the yield of α-alkenyl borate is 0%.

[0207] Comparative Example 4

[0208] The difference between Comparative Example 1 and Example 71 is that the bis(bis-catechol) borate in Example 71 is replaced by an equimolar amount of biboronic acid pinacol ester (B2pin2), and the rest is the same as Example 71. It is found that 1,2,2-alkyl triborates cannot be synthesized, that is, the yield of 1,2,2-alkyl triborates is 0%.

[0209] Comparative Example 5

[0210] The difference between Comparative Example 1 and Example 106 is that the bis(bis-catechol) borate in Example 106 is replaced by an equimolar amount of biboric acid pinacol ester (B2pin2), and the other steps are the same as Example 106. It is found that 2,2-alkylbisborate cannot be synthesized, that is, the yield of 2,2-alkylbisborate is 0%.

[0211] In addition, the inventors of this case also referred to the aforementioned embodiments and conducted experiments with other raw materials, process operations, and process conditions described in this specification, and obtained relatively ideal results.

[0212] It can be seen that the present invention uses biboric acid ester as a boronating agent and a proton source as an additive. In an organic solvent, alkynes and the boronating agent undergo Markovnikov hydroboration or polyboration reaction to selectively prepare compounds such as α-alkenyl borate, 1,2,2-alkyl triborates, 1,2-alkyl diborates or 2,2-alkyl diborates. The present invention does not require metals and complex ligands, is simple to operate, has low cost, good selectivity, is easy to scale up, and can conveniently regulate the structure of the target product by adjusting the type of proton additive and the solvent; and the target product can participate in various types of transformations, and has potential application value in the preparation of medicines, pesticides, functional materials, etc.

[0213] The above embodiments are only for explaining the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing α-alkenyl borate by Markovnikov hydroboration of alkynes, characterized in that: include: A first mixed reaction system containing an alkyne compound, a borating agent, an additive and a solvent is subjected to a Markovnikov hydroboration reaction; wherein the alkyne compound contains at least one carbon-carbon triple bond at a terminal position, the borating agent comprises a biborate, the additive comprises a proton source, and the solvent comprises an organic solvent.

2. The method according to claim 1, characterized in that: The biboric acid ester comprises bis( ... And / or, the organic solvent includes any one or a combination of two or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, hexamethylphosphoric triamide, 1,4-dioxane, ethylene glycol dimethyl ether, toluene, 1,2-dichloroethane, acetonitrile or methanol, preferably includes N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and more preferably includes N,N-dimethylformamide; And / or, the proton source includes one or a combination of water, alcohol compounds, carboxylic acid compounds, amide compounds, phenylboronic acid compounds, and phenolic compounds; And / or, the alkyne compound comprises C 4-22 Alkyl alkynes, C 8-20 One or more combinations of aryl alkynes; And / or, the first mixed reaction system does not contain a metal-containing catalyst.

3. The method according to claim 2, characterized in that: The alcohol compound includes one or more of methanol, ethanol, n-propanol, isopropanol, tert-butanol, trifluoroethanol, and pinacol; the carboxylic acid compound includes benzoic acid; the amide compound includes p-toluamide; the phenylboric acid compound includes phenylboric acid; the phenol compound includes one or more of phenol, p-cyanophenol, p-methoxyphenol, p-diphenol, m-diphenol, o-diphenol, and 2,6-di-tert-butyl-4-methylphenol; And / or, the proton source includes the phenolic compound.

4. The method according to claim 1, characterized in that: The temperature of the Markovnikov hydroboration reaction is 25 to 100° C. And / or, the Markovnikov hydroboration reaction time is 6 to 36 hours; and / or, the molar ratio of the biboric acid ester to the alkyne compound is 1 to 3:1; and / or, the molar ratio of the proton source to the alkyne compound is 1 to 5:1; and / or, the amount of the organic solvent used is such that the total molar concentration of the alkyne compound, the boronating agent, and the additive is 0.2 to 3.5 mol / L; And / or, the method further comprises: after the Markovnikov hydroboration reaction is completed, adding pinacol to the product obtained by the reaction to obtain α-alkenyl borate.

5. An α-alkenyl borate, characterized in that: It is prepared by the method described in any one of claims 1 to 4.

6. A method for preparing polyboric acid ester compounds by polyboration of alkynes, characterized in that: include: A second mixed reaction system containing an alkyne compound, a borating agent, an additive and a solvent is subjected to a polyboration reaction; wherein the alkyne compound contains at least one carbon-carbon triple bond at a terminal position, the borating agent comprises a diborate, the additive comprises a proton source, and the solvent comprises an organic solvent.

7. The method according to claim 6, characterized in that: The biboric acid ester comprises bis( ... And / or, the organic solvent includes any one or a combination of two or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, hexamethylphosphoric triamide, dimethyl sulfoxide, 1,4-dioxane, ethylene glycol dimethyl ether, toluene, 1,2-dichloroethane, acetonitrile, and methanol, preferably includes one or more of N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone; And / or, the proton source includes one or a combination of water, alcohol compounds, carboxylic acid compounds, sulfonic acid compounds, phenylboronic acid compounds, and phenolic compounds; And / or, the alkyne compound comprises C 4-22 Alkyl alkynes, C 8-20 One or more combinations of aryl alkynes; And / or, the second mixed reaction system does not contain a metal-containing catalyst.

8. The method according to claim 7, characterized in that: The alcohol compound includes one or more of methanol, ethanol, n-propanol, isopropanol, tert-butanol, and hexafluoroisopropanol; the carboxylic acid compound includes one or more of benzoic acid, isotribenzoic acid, p-dibenzoic acid, acetic acid, and trifluoroacetic acid; the sulfonic acid compound includes methanesulfonic acid and / or p-toluenesulfonic acid; the phenylboric acid compound includes phenylboric acid; the phenol compound includes one or more of p-cyanophenol, p-methoxyphenol, p-diphenol, m-diphenol, o-diphenol, and 2,6-di-tert-butyl-4-methylphenol; And / or, the proton source includes water and / or the carboxylic acid compound.

9. The method according to claim 6, characterized in that: The temperature of the polyboration reaction is 60-100°C; And / or, the polyboration reaction time is 12 to 36 hours; and / or, the molar ratio of the biboric acid ester to the alkyne compound is 1 to 3:1; and / or, the molar ratio of the proton source to the alkyne compound is 1 to 5:1; and / or, the amount of the organic solvent used is such that the total molar concentration of the alkyne compound, the boronating agent, and the additive is 0.2 to 3.5 mol / L; And / or, the method further comprises: after the polyboration reaction is completed, adding pinacol to the product obtained by the reaction to obtain a polyborate ester compound.

10. A polyborate compound, characterized in that: It is prepared by the method described in any one of claims 7 to 9; Preferably, the polyborate compound is 1,2,2-alkyl triborate, 1,2-alkyl bisborate or 2,2-alkyl bisborate.

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