Triarylboranes, methods for their preparation and use

Abstract

This invention discloses a triarylborane, its preparation method, and its applications. The triarylborane of this invention has the structural formula shown in Formula II. The preparation method of the compound shown in Formula II includes the following steps: In an inert atmosphere, a solution of bromoaromatic or iodoaromatic hydrocarbons in diethyl ether is stirred and a solution of isopropyl magnesium chloride in diethyl ether is added dropwise; after the addition is complete, the reaction is continued with stirring to obtain a mixed solution; in an inert atmosphere, the mixed solution is mixed and reacted with a suspension of the compound shown in Formula I of claim 1 in diethyl ether; the solvent is removed from the mixture, the residue is dissolved in toluene, and trimethylchlorosilane is added and the reaction is stirred to obtain the compound shown in Formula II, which is the triarylborane. This invention uses Grignard reagents prepared in situ from different diaryl difluoroborate potassium and haloaromatic hydrocarbons to flexibly synthesize a series of triarylboranes with different functional groups, characterized by the fact that the three aryl substituents are all different.

Description

Technical Field

[0001] This invention belongs to the field of boron chemical synthesis, and relates to a triarylborane, its preparation method and application. Background Technology

[0002] Triarylboranes have wide applications as Lewis acid catalysts (Warren E. Piers and Tristram Chivers. Chem. Soc. Rev., 1997, 26, 345-354). Among them, hindered Lewis acid-base pairs (FLPs) formed by triarylboranes and organic bases possess unique hydrogen cracking capabilities and can catalytically hydrogenate unsaturated substrates, attracting widespread attention from scientists in recent years (Gregory C. Welch and Douglas W. Stephan. J. Am. Chem. Soc. 2007, 129, 7, 1880–1881; Martin Oestreich, Julia Hermeke and Jens Mohr. Chem. Soc. Rev., 2015, 44, 2202-2220; Jolie Lam, Kevin M. Szkop, Eliar Mosaferi and Douglas W. Stephan. Chem. Soc. Rev., 2019, 48, 3592-3612. The Lewis acidity of triarylboranes is influenced by their aromatic ring substituents and significantly affects the performance of the corresponding catalytic systems. Therefore, adjusting the Lewis acidity of triarylboranes is crucial for the development of such catalytic systems. Although the Lewis acidity of mesityleneboranes can be adjusted by changing the aryl substituents on the triarylborane, making the three aryl substituents on the boron group different is considered a more effective method for fine-tuning the Lewis acidity of triarylboranes. Several methods have been developed for synthesizing triarylboranes with different aryl substitutions (Jamie L. Carden, Ayan Dasgupta and Rebecca L. Melen. Chem. Soc. Rev., 2020, 49, 1706-1725). However, most of these methods are limited to boranes with two aryl substitutions. Effective synthetic methods are still lacking for boranes with three different substituents, especially those that are electron-deficient.

[0003] The synthesis of such boranes typically requires the sequential addition of aryl substituents to the boron atom. The few existing reports all have significant substrate limitations, yielding only trisubstituted boranes with specific structures (Kshitij Parab, Krishnan Venkatasubbaiah, and Frieder). J. Am. Chem. Soc. 2006, 128, 39, 12879-12885; Masato Ito, Emi Ito, Masato Hirai and Shigehiro Yamaguchi. J. Org. Chem. 2018, 83, 15, 8449-8456. These synthetic methods often require aromatic and heteroaromatic rings with sterically hindered substituents to stabilize the boron center, resulting in weak Lewis acidity and making them unsuitable as Lewis acid catalysts. Only one example of a borane composed of three different electron-deficient aromatic rings exists, with strictly limited functional groups (Blagg, R. and Wildgoose, G. RSC Adv. 2016, 6, 42421-42427). Furthermore, these reports often involve cumbersome synthetic and purification processes, and typically require the use of water- and oxygen-sensitive, tedious preparation of diarylboron halide intermediates and harmful organometallic reagents, greatly limiting the practical application of these synthetic methods. Therefore, developing a synthetic method that is easy to operate, produces stable and easy-to-store diarylboride intermediates, and allows for the flexible adjustment of aryl substituents to obtain a variety of triarylboranes is a problem to be solved in this field. Summary of the Invention

[0004] The purpose of this invention is to provide a triarylborane, its preparation method, and its applications. The three aryl substituents on the boron group are all different. This method is based on a key precursor, potassium diaryldifluoroborate, which is stable to water and oxygen and can be stored for a long time. By using different potassium diaryldifluoroborates and Grignard reagents prepared in situ from haloaromatic hydrocarbons, a series of triarylboranes with different functional groups can be flexibly synthesized, characterized by the fact that the three aryl substituents are all different. The series of boranes provided by this method can be adapted to the catalytic hydrogenation of different solvent systems and different substrates.

[0005] The present invention provides a compound having the structural formula shown in Formula I:

[0006]

[0007] In Equation I, R1, R5, R6 and R 10 The groups are sterically unhindered and are independently selected from hydrogen and fluorine, respectively; R2, R3, R4, R7, R8 and R9 are independently selected from hydrogen, halogen, substituted or unsubstituted alkyl groups having 1 to 4 carbon atoms, substituted or unsubstituted phenyl groups, respectively.

[0008] Among them, R1 and R6, R2 and R7, R3 and R8, R4 and R9, R5 and R 10 The five groups cannot be the same at the same time, and R1 and R 10 The five pairs of R2 and R9, R3 and R8, R4 and R7, and R5 and R6 cannot be the same at the same time.

[0009] In this invention, the two substituted phenyl groups on the boron in Formula I are not the same.

[0010] In this invention, the halogen is selected from fluorine, chlorine, bromine or iodine.

[0011] According to the present invention, in a preferred embodiment, R3 and R8 are selected from fluorine, trifluoromethyl, or pentafluorophenyl, and R2, R4, R7, R9, R 12 R 14 Selected from hydrogen or fluorine, R2, R4, R7, R9, R 12 R 14 It is fluorine.

[0012] In this invention, the compound shown in the formula (also known as potassium diaryldifluoroborate) is specifically the compound shown in the following formula:

[0013]

[0014] The present invention also provides a compound having the structural formula shown in Formula II:

[0015]

[0016] In formula II, R1, R2, R3, R4, R5, R6, R7, R8, R9, R 10 R 11 R 12 R 13 R 14 and R 15 Each is independently selected from hydrogen, halogen, substituted or unsubstituted alkyl groups having 1 to 4 carbon atoms, or substituted or unsubstituted phenyl groups;

[0017] Among them, R1, R6 and R 11 R2, R7 and R 12 R3, R8 and R 13 R4, R9 and R 14 R5, R 10 With R 15 The five groups cannot be the same at the same time, and R1, R6 and R... 15 R2, R7 and R 14 R3, R8 and R 13 R4, R9 and R 12 R5, R 10 With R 11 The five groups cannot be the same at the same time, and R1 and R2 are also different. 10 With R 11 R2, R9 and R 12 R3, R8 and R 13 R4, R7 and R 14 R5, R6 and R 15The five groups cannot be the same at the same time, and R1 and R2 are also different. 10 With R 15 R2, R9 and R 14 R3, R8 and R 13 R4, R7 and R 12 R5, R6 and R 11 The five groups cannot be the same at the same time.

[0018] In this invention, the three substituted phenyl groups on the boron in Formula II are all different.

[0019] In this invention, in Formula II, R1, R5, R6 and R 10 These are sterically hindrance-free groups, independently selected from hydrogen and fluorine;

[0020] Among them, R2, R3, R4, R7, R8, R9, R 11 R 12 R 13 R 14 and R 15 Each is independently selected from hydrogen, halogen, substituted or unsubstituted alkyl groups having 1 to 4 carbon atoms, or substituted or unsubstituted phenyl groups; in this case, Formula II is synthesized from Formula I, and the structural formula corresponding to Formula I is written.

[0021] According to the nomenclature of structural formulas in this field, the three benzene ring substituents in Formula II are not distinguished by their order; therefore, R1, R2, R3, R4, R5, R6, R7, R8, R9, R 10 R 11 R 12 R 13 R 14 and R 15 Each is independently selected from hydrogen, halogen, substituted or unsubstituted alkyl groups having 1 to 4 carbon atoms, or substituted or unsubstituted phenyl groups.

[0022] According to the present invention, in a preferred embodiment, R3, R8, R 13 Selected from hydrogen, fluorine, or pentafluorophenyl, R2, R4, R7, R9, R 12 R 14 Selected from hydrogen or fluorine, R1, R5, R6, R 10 R 11 R 15 Selected from fluorine, chlorine, or pentafluorophenyl, and when R1, R5, R6, R 10 R 11 R 15 When one of them is a pentafluorophenyl, the rest are all fluorine, and R1 and R5, R6 and R... 10 R 11 and R 15 When one group consists entirely of chlorine, the rest of the groups consist entirely of fluorine.

[0023] In this invention, the compound represented by Formula II (also known as a triarylborane) is specifically the compound shown in the following formula:

[0024]

[0025] The present invention also provides a method for preparing the compound shown in Formula I, comprising the following steps:

[0026] Under an inert atmosphere and at -78°C, a solution of n-butyllithium in hexane was added dropwise to an ether solution of bromoaromatic or iodoaromatic hydrocarbons while stirring. After the addition was complete, the reaction was stirred. Then, an ether solution of a monoarylborane dimethyl sulfide complex was added and stirred. Next, trimethylchlorosilane was added and stirred. Finally, methanol was added and stirred. The solvent was then removed by filtration, and the residue was dissolved in methanol. Potassium hydrogen fluoride was then added and stirred to obtain the compound shown in Formula I, which is potassium diaryldifluoroborate.

[0027] In the above preparation method, the molar ratio of the brominated aromatic hydrocarbon or iodoaromatic hydrocarbon to the n-butyllithium, the monoarylborane dimethyl sulfide complex, the trimethylchlorosilane, the methanol, and the potassium hydrogen fluoride can be 1:1 to 1.2:1:1 to 2:3 to 6:1 to 1.5, specifically 1:1:1:3:1;

[0028] The stirring time after the addition of n-butyllithium can be 0.5 to 2 hours, specifically 1 hour;

[0029] The stirring time for adding the diethyl ether solution of the monoarylborane dimethyl sulfide complex can be 1 to 3 hours, specifically 1 hour or 1 to 2 hours;

[0030] The stirring time after adding the trimethylchlorosilane can be 1 to 2 hours, specifically 1 hour or 1 to 1.5 hours;

[0031] The stirring time after adding the methanol can be 1 to 2 hours, specifically 1.5 hours, 1 to 1.5 hours, or 1.5 to 2 hours.

[0032] The stirring time after adding the potassium hydrogen fluoride can be 12 to 24 hours, specifically 12 hours or 12 to 20 hours;

[0033] The inert atmosphere is a nitrogen atmosphere.

[0034] In the above preparation method, the treatment process after adding the potassium hydrogen fluoride and stirring the reaction is as follows: filtration, removal of solvent, and slurrying with dichloromethane petroleum ether at a volume ratio of 1:1, filtration, and drying of the filter cake at 60-80°C for 2-5 hours (specifically, vacuum drying at 70°C for 3 hours).

[0035] The present invention also provides a method for preparing the compound shown in Formula II, comprising the following steps: in the inert atmosphere, stirring and dropwise adding an ether solution of isopropyl magnesium chloride to a brominated aromatic hydrocarbon or an iodoaromatic hydrocarbon, and continuing to stir the reaction after the addition is complete to obtain a mixed solution;

[0036] In the inert atmosphere, the mixed solution is mixed and stirred with an ether suspension of the compound of formula I as described in claim 1; the solvent is removed from the mixture, the residue is dissolved in toluene, and trimethylchlorosilane is added and stirred to obtain the compound of formula II, which is triarylborane.

[0037] In the above preparation method, the molar ratio of the brominated aromatic hydrocarbon or iodoaromatic hydrocarbon, isopropyl magnesium chloride, potassium diaryldifluoroborate, and trimethylchlorosilane can be 1:1 to 1.1:1 to 1.1:1 to 3, specifically 1:1:1:3 or 1:1:1:1;

[0038] The stirring time after adding the isopropyl magnesium chloride can be 1 to 3 hours, specifically 1 hour or 1 to 2 hours;

[0039] The stirring time after adding the potassium diaryl difluoroborate can be 12 to 24 hours, specifically 12 hours or 12 to 20 hours.

[0040] In the above preparation method, the post-treatment after the reaction of the added trimethylchlorosilane is complete is as follows: remove the solvent from the system by vacuum distillation, add n-hexane and ultrasonically break up the blocky residue, transfer to a glove box for filtration, remove the solvent by vacuum distillation, recrystallize the residue with n-hexane at -20°C, filter the crystals and wash with n-hexane and dry.

[0041] The present invention further provides that the compound shown in Formula II can be used as a hindered Lewis acid-base pair catalyst in the hydrogenation reaction of aldehydes, ketones or imines to obtain the corresponding reduction product alcohol or amine.

[0042] In this invention, the method for using the compound represented by Formula II as a hindered Lewis acid-base pair catalyst for the hydrogenation reaction of aldehydes, ketones, or imines includes the following steps:

[0043] Under hydrogen atmosphere and heating conditions, the triarylborane shown in Formula II is stirred with an aldehyde, ketone or imine in a solvent to obtain the corresponding reduction product alcohol or amine.

[0044] In the above preparation method, the molar ratio of the triarylborane to the aldehyde, ketone or imine can be 0.05 to 0.1:1;

[0045] The reaction is carried out in a high-pressure reactor, and the hydrogen atmosphere pressure can be 2 to 5 MPa.

[0046] The heating conditions can be 50 to 120 degrees Celsius, and the reaction time can be 3 to 72 hours;

[0047] The solvent is selected from diethyl ether, tetrahydrofuran, or toluene.

[0048] In the above preparation method, the post-processing after the reaction is as follows: the product is separated and purified by column chromatography using 200-300 mesh silica gel as the column packing material and a mixture of petroleum ether and ethyl acetate in a volume ratio of 20:1 to 5:1 as the eluent.

[0049] The present invention has the following beneficial effects:

[0050] This invention provides a method for synthesizing novel triarylboranes by sequentially adding groups, wherein the three aryl substituents on the boron are all different. The arylborane dimethyl sulfide complex is reacted with an aryl metal reagent in diethyl ether, followed by treatment with trimethylchlorosilane, methanol, and potassium hydrogen fluoride to obtain potassium diaryl difluoroborate of Formula I. The aforementioned potassium diaryl difluoroborate of Formula I is then reacted with an aryl metal reagent in diethyl ether, followed by treatment with trimethylchlorosilane to obtain triarylborane of Formula II. This method features a short synthesis procedure, mild reaction conditions, and good group compatibility. It can synthesize a series of triarylboranes with different aryl substituents, each adaptable to catalytic hydrogenation in different solvent systems and with different substrates, demonstrating flexible control over the triarylboranes. This method avoids sensitivity to water and oxygen, the cumbersome preparation of diarylborane halide intermediates, and the use of harmful organometallic reagents. The synthesized diaryl difluoroborate intermediates are stable to air and moisture, can be stored for extended periods, and have potential application value. Attached Figure Description

[0051] Figure 1 This is a schematic diagram of the process of this invention. Detailed Implementation

[0052] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0053] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0054] In the following examples, the pentafluorophenylborane dimethyl sulfide complex was prepared according to the following steps:

[0055] Under nitrogen protection, tris(pentafluorophenyl)borane (9.2 g, 18.0 mmol) and 72 mL of anhydrous toluene were added to a 200 mL single-necked reaction flask equipped with a valve. After stirring thoroughly, 6.28 mL of a 10 mol / L dimethyl sulfide solution of the boronane dimethyl sulfide complex (i.e., 62.8 mmol of the boronane dimethyl sulfide complex) was added dropwise. After the addition was complete, the reaction system was heated to 80°C using an oil bath and the temperature was maintained for 2 hours. After the reaction was completed, the reaction system was cooled to room temperature, and the solvent was removed under vacuum to obtain a white solid. The reaction flask was transferred to a glove box, and the residue was recrystallized from dichloromethane and n-hexane at -20°C. The residue was filtered, washed with anhydrous n-hexane, and dried. The mother liquor was removed from the solvent under vacuum, and the recrystallization operation was repeated twice. The products were combined, yielding a total of 11.2 g of white crystals, with a yield of 86%.

[0056] The structure of the pentafluorophenylborane dimethyl sulfide complex is confirmed as follows:

[0057] 1 H NMR (400MHz, CDCl3): δ (ppm) 3.15-1.98 (br m, 2H), 2.25 (s, 6H).

[0058] 19 F NMR (376MHz, CDCl3): δ (ppm)-130.5 (dd, J F-F =24.2Hz,J F-F =9.2Hz,2F),-157.3(t,J) F-F =20.1Hz, 1F), -163.7(m, 2F).

[0059] 11 B NMR(128MHz, CDCl3): δ(ppm)-17.1(t,J B-H =107Hz).

[0060] In the following examples, the preparation method of 2-bromo-2',3,3',4,4',5,5',6,6'-nonafluoro-1,1'-biphenyl is carried out according to the following steps:

[0061] Under nitrogen protection, pentafluorobromobenzene (18.0 g, 72.9 mmol) and 100 mL of anhydrous diethyl ether were added to a 250 mL three-necked flask. After stirring thoroughly, the reaction system was cooled using an ice-water bath, and then 16 mL of a hexane solution of n-butyllithium with a concentration of 2.5 mol / L (i.e., 40 mmol of n-butyllithium) was added dropwise. After the addition was complete, the mixture was brought to room temperature and stirred overnight. After the reaction was completed, the solvent was removed by rotary evaporation, and the residue was transferred to a sublimator for sublimation under reduced pressure to give 11.2 g of white crystals, with a yield of 71%.

[0062] The structure of 2-bromo-2',3,3',4,4',5,5',6,6'-nonafluoro-1,1'-biphenyl is confirmed as follows:

[0063] 19 F NMR (376MHz, CDCl3): δ (ppm) -126.5 (m, 1F), -133.4 (m, 1F), -137.6 (m, 2F), -149.1 (m, 1F), -150.0 (m, 1F), -153.7 (m, 1F), -160.3 (m, 2F).

[0064] In the following examples, the preparation method of 4-iodo-2,2',3,3',4',5,5',6,6'-nonafluoro-1,1'-biphenyl is carried out according to the following steps:

[0065] Under nitrogen protection, in a 250 mL three-necked flask, 16.7 g (50.0 mmol) of decafluorobiphenyl, 0.14 g (0.4 mmol) of ferric acetylacetone, and 20 mL of anhydrous tetrahydrofuran were added. After stirring thoroughly, the reaction system was cooled to -30°C using a cryostat, and then 100 mL of a 1.0 mol / L tetrahydrofuran solution of ethyl magnesium bromide (i.e., 100 mmol of ethyl magnesium bromide) was added dropwise. After the addition was complete, the reaction was carried out at -30°C for 1 hour. Then, 12.7 g (50 mmol) of iodine granules were added, and after the addition was complete, the reaction was allowed to proceed to room temperature for 2 days. After the reaction was completed, the reaction was quenched with 50 mL of saturated ammonium chloride aqueous solution and 50 mL of saturated sodium thiosulfate aqueous solution, and extracted with diethyl ether (3 × 50 mL). The combined organic phases were dried over anhydrous sodium sulfate. The solvent was removed by filtration and rotary evaporation. The residue was transferred to a sublimator for sublimation under reduced pressure to obtain 15.4 g of yellow crystals, with a yield of 69%.

[0066] The structure of 4-iodo-2,2',3,3',4',5,5',6,6'-nonafluoro-1,1'-biphenyl is confirmed as follows:

[0067] 19 F NMR (376MHz, CDCl3): δ (ppm) -118.6 (m, 2F), -136.3 (m, 2F), -137.2 (m, 2F), -149.7 (m, 1F), -160.3 (m, 2F).

[0068] Example 1

[0069] Preparation of the compound shown in formula (I-1):

[0070]

[0071] Under nitrogen protection, 2,4,6-trifluorobromobenzene (2.11 g, 10 mmol) and 10 mL of anhydrous diethyl ether were added to a 100 mL single-necked reaction flask with a glass valve. After stirring thoroughly, the reaction system was cooled to -78°C using a dry ice-ethanol bath. Then, 6.25 mL of a 1.6 mol / L hexane solution of n-butyllithium (i.e., 10 mmol of n-butyllithium) was slowly added dropwise using a syringe. After the addition was complete, the reaction was maintained at -78°C for 1 hour. Then, a solution of pentafluorophenylborane dimethyl sulfide complex (2.42 g, 10 mmol) dissolved in 10 mL of anhydrous diethyl ether was rapidly added, and the reaction was maintained at -78°C for 1 hour. The dry ice-ethanol bath was then removed, and the reaction was allowed to proceed to room temperature for 1 hour. Finally, trimethylchlorosilane (1.09 g, 10 mmol) was added, and the reaction was continued at room temperature for 1 hour, during which a white precipitate gradually formed. Then, anhydrous methanol (0.96 g, 30 mmol) was slowly added dropwise using a syringe, during which a violent gas was generated. After the addition was complete, the reaction was allowed to proceed for 1.5 hours. After the reaction was complete, the reaction solution was filtered through a filter membrane, and the filter cake was washed with petroleum ether. The filtrate was concentrated by rotary evaporation to remove the solvent. 40 mL of methanol was added to dissolve the remaining oily substance, and the mixture was transferred to a plastic reaction flask. Potassium hydrogen fluoride (0.78 g, 10 mmol) was added, and the mixture was stirred overnight at room temperature (12 hours). After the reaction was complete, the reaction solution was filtered, and the filter cake was washed with acetone. The filtrate was concentrated by rotary evaporation to remove the solvent, yielding a white lumpy solid. After crushing, the solid was slurried with a 1:1 mixture of dichloromethane and petroleum ether and filtered through a filter membrane. The filter cake was vacuum dried at 70°C for 3 hours to obtain 3.56 g of potassium diaryldifluoroborate (I-1) as a white powder, with a yield of 92%.

[0072] The product identification results are as follows:

[0073] 1 H NMR (400MHz, CD3OD): δ (ppm) 6.46 (t, J F-H =8.7Hz, 2H).

[0074] 13 C NMR (100MHz, CD3OD): δ (ppm) 167.5 (dm, J C-F =240Hz,2C,CF),163.3(dt,J C-F =241Hz,J C-F =16.6Hz, 1C, CF), 149.1 (dm, J) C-F =238Hz,2C,CF),141.1-135.3(m,3C,CF),99.7(m,2C,CH).

[0075] 19F NMR (376MHz, CD3OD): δ (ppm) -102.6 (m, 2F), -113.2 (m, 1F), -136.0 (m, 2F), -146.5 (br, 2F), -161.3 (t, J F-F =19.2Hz,1F),-165.6(m,2F).

[0076] 11 B NMR (128MHz, CD3OD): δ (ppm) 5.08 (br t,J B-F =63Hz).

[0077] HRMS(ESI)calcd.for C 12 H2BF 10 - [MK] - :347.0095,Found:347.0089.

[0078] Example 2

[0079] Preparation of the compound shown in formula (I-2):

[0080]

[0081] Under nitrogen protection, 4.42 g (10 mmol) of 4-iodo-2,2',3,3',4',5,5',6,6'-nonafluoro-1,1'-biphenyl and 10 mL of anhydrous diethyl ether were added to a 100 mL single-necked reaction flask with a glass valve. After stirring thoroughly, the reaction system was cooled to -78°C using a dry ice-ethanol bath. Then, 6.25 mL (10 mmol) of a hexane solution of n-butyllithium at a concentration of 1.6 mol / L was slowly added dropwise using a syringe. After the addition was complete, the reaction was maintained at -78°C for 1 hour. Then, a solution of pentafluorophenylborane dimethyl sulfide complex (2.42 g, 10 mmol) dissolved in 10 mL of anhydrous diethyl ether was rapidly added, and the reaction was maintained at -78°C for 1 hour. Finally, the dry ice-ethanol bath was removed, and the reaction was allowed to proceed to room temperature for 1 hour. Then, trimethylchlorosilane (1.09 g, 10 mmol) was added, and the reaction was carried out at room temperature for 1 hour, during which a white precipitate gradually formed. Then, anhydrous methanol (0.96 g, 30 mmol) was slowly added dropwise using a syringe, during which a gas was violently generated. After the addition was complete, the reaction was allowed to proceed for 1.5 hours. After the reaction was complete, the reaction solution was filtered through a filter membrane, and the filter cake was washed with petroleum ether. The filtrate was concentrated by rotary evaporation to remove the solvent. 40 mL of methanol was added to dissolve the remaining oily substance, and the solution was transferred to a plastic reaction flask. Potassium hydrogen fluoride (0.78 g, 10 mmol) was added, and the reaction was stirred overnight at room temperature. After the reaction was complete, the reaction solution was filtered, and the filter cake was washed with acetone. The filtrate was concentrated by rotary evaporation to remove the solvent, yielding a white lumpy solid. After crushing, the solid was slurried with a 1:1 mixture of dichloromethane and petroleum ether and filtered through a filter membrane. The filter cake was vacuum dried at 70°C for 3 hours to obtain 4.80 g of potassium diarylfluoroborate (I-2) as a white powder, with a yield of 84%.

[0082] The product identification results are as follows:

[0083] 13 C NMR (100MHz, CD3OD): δ (ppm) 149.3 (dm, J C-F =238Hz, 4C, CF), 145.9 (dm, J) C-F =242Hz,2C,CF),144.6(dm,J) C-F =247Hz,2C,CF),142.0-136.7(m,6C,CF),105.0(m,C-Ar),104.0(m,C-Ar).

[0084] 19 F NMR (376MHz, CD3OD): δ (ppm) -137.5 (m, 2F), -138.0 (m, 2F), -140.5 (m, 2F), -144.4 (m, 2F), -149.6 (br, 2F), -155.1 (t, J F-F=20.2Hz, 1F), -163.2(t, J) F-F =19.2Hz,1F),-164.5(m,2F),-168.0(m,2F).

[0085] 11 B NMR (128MHz, CD3OD): δ (ppm) 4.73 (br t,J B-F =56Hz).

[0086] HRMS(ESI)calcd.for C 13 BF 14 - [MK] - :432.9875,Found:432.9866.

[0087] Example 3

[0088] Preparation of the compound shown in formula (I-3):

[0089]

[0090] Under nitrogen protection, 2.97 g (10 mmol) of 4-trifluoromethyl-2,3,5,6-tetrafluorobromobenzene and 10 mL of anhydrous diethyl ether were added to a 100 mL single-necked reaction flask equipped with a valve. After stirring thoroughly, the reaction system was cooled to -78°C using a dry ice-ethanol bath. Then, 6.25 mL (10 mmol) of a hexane solution of 1.6 mol / L n-butyllithium was slowly added dropwise using a syringe. After the addition was complete, the reaction was maintained at -78°C for 1 hour. Then, a solution of 2.42 g (10 mmol) of pentafluorophenylborane dimethyl sulfide complex dissolved in 10 mL of anhydrous diethyl ether was rapidly added, and the reaction was maintained at -78°C for 1 hour. The dry ice-ethanol bath was then removed, and the reaction was allowed to proceed to room temperature for 1 hour. Finally, 1.09 g (10 mmol) of trimethylchlorosilane was added, and the reaction was continued at room temperature for 1 hour, during which a white precipitate gradually formed. Then, anhydrous methanol (0.96 g, 30 mmol) was slowly added dropwise using a syringe, during which a violent gas was generated. After the addition was complete, the reaction was allowed to proceed for 1.5 hours. After the reaction was complete, the reaction solution was filtered through a filter membrane, and the filter cake was washed with petroleum ether. The filtrate was concentrated by rotary evaporation to remove the solvent. 40 mL of methanol was added to dissolve the remaining oily substance, and the solution was transferred to a plastic reaction flask. Potassium hydrogen fluoride (0.78 g, 10 mmol) was added, and the mixture was stirred overnight at room temperature. After the reaction was complete, the reaction solution was filtered, and the filter cake was washed with acetone. The filtrate was concentrated by rotary evaporation to remove the solvent, yielding a white lumpy solid. After crushing, the solid was slurried with a 1:1 mixture of dichloromethane and petroleum ether and filtered through a filter membrane. The filter cake was vacuum dried at 70°C for 3 hours to obtain 3.98 g of potassium diaryldifluoroborate (I-3) as a white powder, with a yield of 84%.

[0091] The product identification results are as follows:

[0092] 13 C NMR (100MHz, CD3OD): δ (ppm) 150.7-148.1 (m, 4C, CF), 144.5 (ddm, J C-F =256Hz,J C-F =22.7Hz,2C,CF),141.9-136.9(m,2C,CF),122.7(m,1C,C-CF3),107.4(m,1C,CF3).

[0093] 19 F NMR(376MHz,CD3OD): δ(ppm)-57.8(t,J F-F =21.7Hz,3F,CF3)-136.9(m,2F),-138.7(m,2F),-146.3(m,2F),-150.0(br,2F),-162.5(t,J F-F =19.1Hz, 1F), -167.6(m, 2F).

[0094] 11 B NMR (128MHz, CD3OD): δ (ppm) 4.68 (br).

[0095] HRMS(ESI)calcd.for C 18 BF 16 - [MK] - :530.9843,Found:530.9833.

[0096] Example 4

[0097] Preparation of the compound shown in formula (II-1):

[0098]

[0099] Under nitrogen protection at room temperature (25°C), 1.145 g (5.0 mmol) of 1-bromo-2,3,5,6-tetrafluorobenzene and 25 mL of anhydrous diethyl ether were added to a 50 mL two-necked flask. After stirring thoroughly, 3.8 mL (5.0 mmol) of an ether solution of 1.3 mol / L isopropyl magnesium chloride was slowly added dropwise using a syringe. After the addition was complete, the reaction was allowed to proceed at room temperature for 1 hour. Simultaneously, under nitrogen protection, 1.93 g (5.0 mmol) of potassium diaryldifluoroborate (as shown in Formula (I-1) and 25 mL of anhydrous diethyl ether were added to a 100 mL single-necked reaction flask with a valve, and the mixture was stirred until the reaction system became a homogeneous, fine white slurry. The completely reacted solution from the 50 mL two-necked flask was then transferred to the 100 mL reaction flask and stirred overnight (12 hours). During this time, the insoluble substances in the reaction system gradually became easier to settle. After the reaction was complete, the solvent in the reaction system was removed under vacuum, yielding a pale yellow to white solid. Nitrogen gas was then introduced into the reaction flask, and approximately 25 mL of anhydrous toluene was added at room temperature to dissolve the residue, forming a turbid yellow solution. Trimethylchlorosilane (1.63 g, 15 mmol) was then added to the reaction system, and the mixture was stirred at room temperature for one hour. After the reaction was complete, the solvent in the reaction system was removed under vacuum, yielding a pale yellow to white solid. Nitrogen gas was then introduced into the reaction flask, and approximately 25 mL of anhydrous n-hexane was added. The lumpy residue was thoroughly broken up by sonication, and the reaction flask was gently heated. The reaction flask was transferred to a glove box, and the mixture was filtered hot using a filter membrane. The filter cake was washed three times with approximately 10 mL of hot anhydrous n-hexane. The filtrate was concentrated under vacuum to obtain a yellow oil or a yellow solid. A small amount of anhydrous n-hexane was added, and the mixture was recrystallized at -20°C. The crystals were filtered, washed with anhydrous n-hexane, and dried to obtain 0.81 g of yellow-green crystals of triarylborane as shown in formula (II-1), with a yield of 35%.

[0100] The product identification results are as follows:

[0101] 1 H NMR (400MHz, CDCl3): δ (ppm) 7.16-7.00 (m, 1H), 6.57 (t, J F-H =8.5Hz, 2H).

[0102] 13 C NMR (100MHz, CDCl3): δ (ppm) 168.5 (dt, J C-F =258Hz,J C-F =16.8Hz, 1C, CF), 167.4 (dm, J) C-F =255Hz, 2C, CF), 148.0 (dm, J) C-F =248Hz,2C,CF),147.1(dm,J) C-F=246Hz,2C,CF),146.0(dm,J) C-F =248Hz,2C,CF),145.7-143.1(m,1C,CF),137.7(dm,J C-F =252Hz,2C,CF),120.5(br,1C,CB),114.4(br,1C,CB),113.4(br,1C,CB),110.3(t,J C-F =22.4Hz,CH),101.2(ddd,J C-F =28.7Hz,J C-F =24.8Hz, J C-F =3.5Hz, CH).

[0103] 19 F NMR(376MHz, CDCl3): δ(ppm)-93.3(d,J F-F =11.8Hz,2F),-95.3(br m,1F),-129.2(dm,J F-F =19.5Hz,2F),-130.9(dd,J F-F =22.3Hz,J F-F =14.0Hz,2F),-138.9(dd,J) F-F =22.1Hz,J F-F =13.8Hz,2F),-146.2(br t,J F-F =19.1Hz,1F),-161.4(m,2F).

[0104] 11 B NMR (128MHz, CDCl3): δ (ppm) 59.9 (br).

[0105] HRMS(APCI)calcd.for C 18 H3BF 12 + [M] + :458.0138,Found:458.0142.

[0106] Example 5

[0107] Preparation of the compound shown in formula (II-2):

[0108]

[0109] At room temperature (25°C), under nitrogen protection, 1,3-dichloro-2-iodobenzene (562 mg, 2.06 mmol) and 10 mL of anhydrous diethyl ether were added to a 50 mL two-necked flask. After stirring thoroughly, 1.8 mL of an ether solution of isopropyl magnesium chloride with a concentration of 1.15 mol / L (i.e., 2.06 mmol of isopropyl magnesium chloride) was slowly added dropwise using a syringe. After the addition was complete, the reaction was allowed to proceed at room temperature for 3 hours. Simultaneously, potassium diaryl difluoroborate (795 mg, 2.06 mmol) prepared according to formula (I-1) of Example 1 of this invention and 10 mL of anhydrous diethyl ether were added to a 100 mL single-necked reaction flask with a valve under nitrogen protection. The mixture was stirred until the reaction system became a homogeneous and fine white slurry. Then, the completely reacted solution from the 50 mL two-necked flask was transferred to the 100 mL reaction flask and stirred overnight. During this time, the insoluble substances in the reaction system gradually became easier to settle. After the reaction was complete, the solvent in the reaction system was removed under vacuum, yielding a pale yellow to white solid. Nitrogen gas was then introduced into the reaction flask, and approximately 10 mL of anhydrous toluene was added at room temperature to dissolve the residue, forming a turbid yellow solution. Trimethylchlorosilane (224 mg, 2.06 mmol) was then added to the reaction system, and the mixture was stirred at room temperature for one hour. After the reaction was complete, the solvent in the reaction system was removed under vacuum, yielding a pale yellow to white solid. Nitrogen gas was then introduced into the reaction flask, and approximately 10 mL of anhydrous n-hexane was added. The lumpy residue was thoroughly broken up by sonication, and the reaction flask was gently heated. The reaction flask was transferred to a glove box, and the mixture was filtered hot using a filter membrane. The filter cake was washed three times with approximately 5 mL of hot anhydrous n-hexane. The filtrate was concentrated under vacuum to obtain a yellow oil or a yellow solid. A small amount of anhydrous n-hexane was added, and the mixture was recrystallized at -20°C. The crystals were filtered, washed with anhydrous n-hexane, and dried to obtain 380 g of pale yellow crystals of the triarylborane shown in formula (II-2), with a yield of 41%.

[0110] The product identification results are as follows:

[0111] 1 H NMR (400MHz, CDCl3): δ (ppm) 7.21-7.19 (m, 3H), 6.58 (t, J F-H =8.5Hz, 2H).

[0112] 13 C NMR (100MHz, CDCl3): δ (ppm) 168.2 (dt, J C-F =257Hz,J C-F =16.9Hz, 1C, CF), 167.7 (dm, J) C-F =242Hz,2C,CF),148.7(dm,J) C-F =250Hz, 2C, CF), 144.4 (dm, J) C-F=258Hz,1C,CF),141.6(br,1C,CB),137.6(dddd,J C-F =251Hz,J C-F =18.0Hz, J C-F =12.4Hz, J C-F =5.5Hz,2C,CF),134.9(C-Cl),131.2,127.1,114.1(br,1C,CB),113.1(br,CB),100.9(ddd,J C-F =28.8Hz, J C-F =24.7Hz,J C-F =3.5Hz, CH).

[0113] 19 F NMR(376MHz, CDCl3): δ(ppm)-93.1(d,J F-F =12.3Hz,2F),-96.2(t,J) F-F =12.3Hz, 1F), -128.3(dm, J) F-F =20.3Hz,2F),-146.6(tt,J F-F =19.9Hz, J F-F =4.6Hz, 1F), 161.8(dt, J F-F =20.1Hz, J F-F =7.3Hz, 1F).

[0114] 11 B NMR (128MHz, CDCl3): δ (ppm) 62.2 (br).

[0115] HRMS(APCI)calcd.for C 18 H5BCl2F8 + [M] + :453.9734,Found:453.9739.

[0116] Example 6

[0117] Preparation of the compound shown in formula (II-3):

[0118]

[0119] Under nitrogen protection at room temperature, 1.97 g (5.0 mmol) of 2-iodo-2',3,3',4,4',5,5',6,6'-nonafluoro-1,1'-biphenyl and 25 mL of anhydrous diethyl ether were added to a 50 mL two-necked flask. After stirring thoroughly, 2.5 mL of an ether solution of 2.0 mol / L magnesium isopropyl chloride (i.e., 5.0 mmol of magnesium isopropyl chloride) was slowly added dropwise using a syringe. After the addition was complete, the reaction was allowed to proceed at room temperature for 1 hour. Simultaneously, under nitrogen protection, 1.93 g (5.0 mmol) of potassium diaryldifluoroborate (as shown in Formula (I-1)) and 25 mL of anhydrous diethyl ether, prepared according to Example 1 of this invention, were added to a 100 mL single-necked reaction flask with a valve, and the mixture was stirred until the reaction system became a homogeneous and fine white slurry. The completely reacted solution from the 50 mL two-necked flask was then transferred to a 100 mL reaction flask and stirred overnight. During this time, the insoluble matter in the reaction system gradually became easier to settle. After the reaction was complete, the solvent in the reaction system was removed under vacuum, yielding a pale yellow to white solid. Nitrogen gas was then introduced into the reaction flask, and approximately 25 mL of anhydrous toluene was added at room temperature to dissolve the residue, forming a turbid yellow solution. Trimethylchlorosilane (1.63 g, 15 mmol) was then added to the reaction system, and the mixture was stirred at room temperature for one hour. After the reaction was complete, the solvent in the reaction system was removed under vacuum, yielding a pale yellow to white solid. Nitrogen gas was then introduced into the reaction flask, and approximately 25 mL of anhydrous n-hexane was added. The lumpy residue was thoroughly broken up by sonication, and the reaction flask was gently heated. The reaction flask was transferred to a glove box, and the mixture was filtered hot through a filter membrane in the glove box. The filter cake was then rinsed three times with approximately 10 mL of hot anhydrous n-hexane. The filtrate was concentrated under vacuum to obtain a yellow oil or yellow solid. A small amount of anhydrous n-hexane was added and recrystallized at -20 degrees Celsius. The mixture was filtered, washed with anhydrous n-hexane, and dried to obtain 0.50 g of triarylborane as shown in formula (II-3), a pale yellow powder, with a yield of 16%.

[0120] The product identification results are as follows:

[0121] 1 H NMR (400MHz, CDCl3): δ (ppm) 6.73 (t, J F-H =8.6Hz, 2H).

[0122] 13 C NMR (100MHz, CDCl3): δ (ppm) 168.7 (dt, J C-F =259Hz,J C-F =17.2Hz, 1C, CF), 167.6 (dm, J) C-F =255Hz,2C,CF),148.1(dm,J) C-F =249Hz,2C,CF),148.2-141.6(m,8C,CF),144.1(ddm,JC-F =252Hz,J C-F =17.5Hz, 2C, CF), 138.2 (dm, J) C-F =254Hz, 2C, CF), 137.7 (dm, J) C-F =253Hz,2C,CF),122.0(br,1C,CB),114.1(br,1C,CB),113.2(br,1C,CB),110.1(m,1C,C-Ar),102.6(m,1C,C-Ar),101.3(ddd,J C-F =28.6Hz,J C-F =24.7Hz,J C-F =3.3Hz, CH).

[0123] 19 F NMR(376MHz, CDCl3): δ(ppm)-82.9(br,2F),-84.4(br,1F),-128.8(br.d,J F-F =17.5Hz,2F),-130.1(dd,J F-F =20.9Hz,J F-F =13.6Hz,2F),-137.2(m,2F),-138.1(m,2F),-145.6(br,1F),-150.1(t,J F-F =20.6Hz,2F),-160.8(m,2F),-161.1(m,2F).

[0124] 11 B NMR (128MHz, CDCl3): δ (ppm) 59.3 (br).

[0125] HRMS(APCI)calcd.for C 24 H2BF 17 + [M] + :623.9978,Found:623.9984.

[0126] Example 7

[0127] Preparation of the compound shown in formula (II-4):

[0128]

[0129] Under nitrogen protection at room temperature, 1,3-dichloro-2-iodobenzene (562 mg, 2.06 mmol) and 25 mL of anhydrous diethyl ether were added to a 50 mL two-necked flask. After stirring, 3.8 mL of an ether solution of 1.3 mol / L isopropyl magnesium chloride (i.e., 5.0 mmol of isopropyl magnesium chloride) was slowly added dropwise using a syringe. After the addition was complete, the reaction was allowed to proceed at room temperature for 3 hours. Simultaneously, potassium diaryl difluoroborate (2.85 g, 5.0 mmol) prepared according to formula (I-2) of Example 2 of this invention and 25 mL of anhydrous diethyl ether were added to a 100 mL single-necked reaction flask with a valve under nitrogen protection. The mixture was stirred until the reaction system became a homogeneous and fine white slurry. The completely reacted solution from the 50 mL two-necked flask was then transferred to the 100 mL reaction flask and stirred overnight. During this time, the insoluble substances in the reaction system gradually became easier to settle. After the reaction was completed, the solvent in the reaction system was removed under vacuum to obtain a pale yellow to white solid. Nitrogen gas was then introduced into the reaction flask, and approximately 25 mL of anhydrous toluene was added at room temperature to dissolve the residue, forming a turbid yellow solution. Trimethylchlorosilane (1.63 g, 15 mmol) was then added to the reaction system, and the mixture was stirred at room temperature for one hour. After the reaction was complete, the solvent in the reaction system was removed under vacuum, yielding a pale yellow to white solid. Nitrogen gas was then introduced into the reaction flask, and approximately 25 mL of anhydrous n-hexane was added. The lumpy residue was thoroughly sonicated and the reaction flask was gently heated. The reaction flask was transferred to a glove box, and the mixture was filtered hot using a filter membrane. The filter cake was washed three times with approximately 10 mL of hot anhydrous n-hexane. The filtrate was concentrated under vacuum to obtain a yellow oil or yellow solid. A small amount of anhydrous n-hexane was added, and the mixture was recrystallized at -20°C. After filtration, washing with anhydrous n-hexane, and drying, 0.52 g of white crystals of triarylborane (Formula II-4) were obtained, with a yield of 19%.

[0130] The product identification results are as follows:

[0131] 1 H NMR (400MHz, CDCl3): δ (ppm) 7.39-7.29 (m, 3H).

[0132] 13 C NMR (100MHz, CDCl3): δ (ppm) 149.6 (dm, J C-F =253Hz, 2C, CF), 148.2 (dm, J) C-F =251Hz,2C,CF),146.9-144.4(m,1C,CF),144.8(dm,J C-F =252Hz,2C,CF),144.2(ddm,J C-F =253Hz,J C-F =16.9Hz, 2C, CF), 143.0 (dm, J) C-F=257Hz,1C,CF),140.4(br,1C,CB),138.2(dm,J C-F =249Hz,2C,CF),137.8(dm,J) C-F =252Hz,2C,CF),134.9(C-Cl),132.0,127.3,120.5(br m,1C,CB),113.1(br m,1C,CB),111.5(t,J C-F =17.0Hz, 1C, C-Ar), 102.6(tm, J) C-F =17.6Hz, 1C, C-Ar).

[0133] 19 F NMR (376MHz, CDCl3): δ (ppm) -126.6 (m, 2F), -128.1 (dd, J F-F =21.6Hz,J F-F =13.8Hz,2F),-137.1(m,2F),-138.1(m,2F),-142.8(m,1F),-150.0(t,J F-F =20.5Hz,1F),-160.9(m,4F).

[0134] 11 B NMR (128MHz, CDCl3): δ (ppm) 65.4 (br).

[0135] HRMS(APCI)calcd.for C 24 H3BCl2F 14 + [M] + :637.9482,Found:637.9487.

[0136] Example 8

[0137] Preparation of the compound shown in formula (II-5):

[0138]

[0139] Under nitrogen protection at room temperature, 1.97 g (5.0 mmol) of 2-bromo-2',3,3',4,4',5,5',6,6'-nonafluoro-1,1'-biphenyl and 25 mL of anhydrous diethyl ether were added to a 50 mL two-necked flask. After stirring thoroughly, 3.8 mL (5.0 mmol) of an ether solution of 1.3 mol / L isopropyl magnesium chloride was slowly added dropwise using a syringe. After the addition was complete, the reaction was allowed to proceed at room temperature for 3 hours. Simultaneously, 2.85 g (5.0 mmol) of potassium diaryldifluoroborate (as shown in Formula (I-2) of Example 2 of this invention) and 25 mL of anhydrous diethyl ether were added to a 100 mL single-necked reaction flask with a valve, under nitrogen protection. The mixture was stirred until the reaction system became a homogeneous, fine white slurry. The completely reacted solution from the 50 mL two-necked flask was then transferred to a 100 mL reaction flask and stirred overnight. During this time, the insoluble matter in the reaction system gradually became easier to settle. After the reaction was complete, the solvent in the reaction system was removed under vacuum, yielding a pale yellow to white solid. Nitrogen gas was then introduced into the reaction flask, and approximately 25 mL of anhydrous toluene was added at room temperature to dissolve the residue, forming a turbid yellow solution. Trimethylchlorosilane (1.63 g, 15 mmol) was then added to the reaction system, and the mixture was stirred at room temperature for one hour. After the reaction was complete, the solvent in the reaction system was removed under vacuum, yielding a pale yellow to white solid. Nitrogen gas was then introduced into the reaction flask, and approximately 25 mL of anhydrous n-hexane was added. The lumpy residue was thoroughly broken up by sonication, and the reaction flask was gently heated. The reaction flask was transferred to a glove box, and the mixture was filtered hot through a filter membrane in the glove box. The filter cake was then rinsed three times with approximately 10 mL of hot anhydrous n-hexane. The filtrate was concentrated under vacuum to obtain a yellow oil. A small amount of anhydrous n-hexane was added and recrystallized at -20 degrees Celsius. The oil was filtered, washed with anhydrous n-hexane, and dried to obtain 1.38 g of triarylborane as shown in formula (II-5), a white powder with a yield of 34%.

[0140] The product identification results are as follows:

[0141] 13 C NMR (100MHz, CDCl3): δ (ppm) 151.1-136.7 (m, 23C, CF), 126.4 (m, 1C, CB), 120.9 (m, 1C, CB), 113.7 (m, 1C, C-Ar), 112.8 (m, 1C, CB), 111.7 (t, J C-F =18.5Hz, 1C, C-Ar), 107.8(t, J) C-F =18.5Hz, 1C, C-Ar), 102.0(t, J C-F =17.3Hz, 1C, C-Ar).

[0142] 19F NMR (376MHz, CDCl3): δ (ppm) -125.3 (m, 2F), -126.3 (m, 1F), -125.3 (m, 2F), -127.9 (dd, J F-F =21.1Hz,J F-F =14.4Hz,2F),-134.2(m,1F),-136.8(m,2F),-137.6(m,2F),-139.1(br d,J F-F =19.3Hz,2F),-139.6(m,1F),-145.5(td,J F-F =20.2Hz,J F-F =7.7Hz, 1F), -149.0(t, J) F-F =20.6Hz, 1F), -149.4(t, J) F-F =20.3Hz, 1F), -150.8(td, J F-F =22.4Hz, J F-F =6.1Hz,1F),-159.6(m,2F),-160.1(m,2F),-160.3(m,2F).

[0143] 11 B NMR (128MHz, CDCl3): δ (ppm) 62.7 (br).

[0144] HRMS(APCI)calcd.for C 30 BF 23 + [M] + :807.9731,Found:807.9746.

[0145] Example 9

[0146] Preparation of 4-chlorobenzyl alcohol:

[0147] At room temperature, 22.7 mg (0.05 mmol) of triarylborane (Formula II-2) prepared in Example 5 of this invention, 70.3 mg (0.5 mmol) of 4-chlorobenzaldehyde, and 1 mL of anhydrous tetrahydrofuran were added to a reaction tube. After stirring thoroughly, the reaction tube was transferred to a high-pressure reactor, purged with hydrogen gas (2 MPa), and stirred at 50°C for 72 hours. After the reaction was completed, the product was purified by column chromatography using 200-300 mesh silica gel as packing material and a 5:1 (v / v) mixture of petroleum ether and ethyl acetate as eluent, yielding 64.7 mg of a white solid, with a yield of 91%.

[0148] The product identification results are as follows:

[0149] 1 H NMR (400MHz, CDCl3): δ (ppm) 7.36-7.24 (m, 4H), 4.63 (s, 2H), 2.14 (s, 1H).

[0150] 13 C NMR (100MHz, CDCl3): δ (ppm) 139.3, 133.4, 128.8, 128.4, 64.6.

[0151] HRMS(ESI)calcd.for C7H6OCl - [MH] - :141.0113,Found:141.0102.

[0152] Example 10

[0153] Preparation of 4-phenyl-2-butanol:

[0154] In a glove box at room temperature, 11.5 mg of triarylborane (0.025 mmol) of formula (II-1) prepared in Example 5 of this invention, 74.1 mg of 4-phenyl-2-butanone (0.5 mmol), and 1 mL of anhydrous diethyl ether were added to a reaction tube. After stirring thoroughly, the reaction tube was transferred to a high-pressure reactor, purged with hydrogen gas (5 MPa), and stirred at 70°C for 24 hours. After the reaction was completed, the product was purified by column chromatography using 200-300 mesh silica gel as packing material and a 5:1 (v / v) mixture of petroleum ether and ethyl acetate as eluent, yielding 46.4 mg of colorless oil, with a yield of 62%.

[0155] The product identification results are as follows:

[0156] 1 H NMR (400MHz, CDCl3): δ (ppm) 7.32-7.26 (m, 2H), 7.23-7.16 (m, 3H), 3.88-3.78 (m, 1H), 2.81-2.62 (m, 2H), 1.85-1.71 (m, 2H), 1.23 (d, J = 6.2Hz, 3H).

[0157] 13 C NMR (100MHz, CDCl3): δ (ppm) 142.2, 128.5, 126.0, 67.7, 41.0, 32.3, 29.9, 23.8.

[0158] HRMS(APCI)calcd.for C 10 H 15 O + [M+H] +:151.1117,Found:151.1117.

[0159] Example 11

[0160] Preparation of N-(1-([1,1'-biphenyl]-4-yl)ethyl)aniline:

[0161] In a glove box at room temperature, 15.6 mg (0.025 mmol) of triarylborane (Formula II-3) prepared in Example 6 of this invention, 135.6 mg (0.5 mmol) of 1-([1,1'-biphenyl]-4-yl)-N-phenylethane-1-imine, and 2 mL of anhydrous toluene were added to a reaction tube. After stirring thoroughly, the reaction tube was transferred to a high-pressure reactor, purged with hydrogen (5 MPa), and stirred at 120°C for 24 hours. After the reaction was completed, the product was purified by column chromatography using 200-300 mesh silica gel as packing material and a mixture of petroleum ether and ethyl acetate (volume ratio 20:1) as eluent. 117.5 mg of a pale yellow solid was obtained, with a yield of 86%.

[0162] The product identification results are as follows:

[0163] 1 H NMR (400MHz, CDCl3): δ (ppm) 7.62-7.53 (m, 4H), 7.48-7.40 (m, 4H), 7.37-7.30 (m, 1H), 7.16-7.09 (m, 2 H),6.71-6.64(m,1H),6.59-6.53(m,2H),4.55(q,J=6.7Hz,1H),4.09(br,1H),1.57(d,J=6.7Hz,3H).

[0164] 13 C NMR (100MHz, CDCl3): δ (ppm) 147.4, 144.4, 141.1, 139.9, 129.3, 128.8, 127.5, 127.3, 127.2, 126.4, 117.5, 113.5, 53.3, 25.1.

[0165] HRMS(APCI)calcd.for C 20 H 20 N + [M+H] + :247.1590,Found:247.1589.

[0166] As demonstrated in Examples 1-3 above, this invention utilizes an arylborane dimethyl sulfide complex reacting with an in-situ generated aryl metal reagent in diethyl ether. After treatment with trimethylchlorosilane, methanol, and potassium hydrogen fluoride, potassium diaryl difluoroborate of Formula I is obtained. This salt is stable to water and oxygen, can be stored in air for extended periods, and can be used as a precursor for the synthesis of triarylboranes, avoiding the complex preparation and difficult storage problems associated with such precursors.

[0167] As demonstrated in Examples 4-8 above, the present invention uses the aforementioned potassium diaryl difluoroborate of Formula I to react with an aryl metal reagent in diethyl ether, followed by treatment with trimethylchlorosilane to obtain the triarylborane shown in Formula II. This method has a short synthetic procedure, mild reaction conditions, and good functional group compatibility.

[0168] As demonstrated in Examples 9-11 above, the various triarylboranes of Formula II prepared by this invention can be used for the catalytic hydrogenation of aldehydes, ketones, or imines in different solvents. The synthetic method provided by this invention allows for flexible adjustment of the aryl substituents on boron to obtain a variety of triarylboranes suitable for catalytic hydrogenation of different substrates in different solvent systems.

Claims

1. A compound having the structural formula shown in Formula I: In Equation I, R1, R5, R6 and R 10 R2, R3, R4, R7, R8 and R9 are each independently selected from hydrogen, halogen, substituted or unsubstituted alkyl groups having 1 to 4 carbon atoms, or substituted or unsubstituted phenyl groups. in, R1 and R6, R2 and R7, R3 and R8, R4 and R9, R5 and R 10 The five groups cannot be the same at the same time, and R1 and R 10 The five pairs of R2 and R9, R3 and R8, R4 and R7, and R5 and R6 cannot be the same at the same time.

2. A compound having the structural formula shown in Formula II: In formula II, R1, R2, R3, R4, R5, R6, R7, R8, R9, R 10 R 11 R 12 R 13 R 14 and R 15 Each is independently selected from hydrogen, halogen, substituted or unsubstituted alkyl groups having 1 to 4 carbon atoms, or substituted or unsubstituted phenyl groups; in, R1, R6 and R 11 R2, R7 and R 12 R3, R8 and R 13 R4, R9 and R 14 R5, R 10 With R 15 The five groups cannot be the same at the same time, and R1, R6 and R... 15 R2, R7 and R 14 R3, R8 and R 13 R4, R9 and R 12 R5, R 10 With R 11 The five groups cannot be the same at the same time, and R1 and R2 are also different. 10 With R 11 R2, R9 and R 12 R3, R8 and R 13 R4, R7 and R 14 R5, R6 and R 15 The five groups cannot be the same at the same time, and R1 and R2 are also different. 10 With R 15 R2, R9 and R 14 R3, R8 and R 13 R4, R7 and R 12 R5, R6 and R 11 The five groups cannot be the same at the same time.

3. A method for preparing the compound of formula I as described in claim 1, comprising the following steps: Under an inert atmosphere and at -78°C, a solution of brominated or iodoaromatic hydrocarbons in diethyl ether was stirred and a solution of n-butyllithium in hexane was added dropwise. After the addition was complete, the reaction was stirred. Then, a solution of monoarylborane dimethyl sulfide complex in diethyl ether was added and stirred. Trimethylchlorosilane was then added and stirred. Finally, methanol was added and stirred. The solvent was then removed by filtration, and the residue was dissolved in methanol. Potassium hydrogen fluoride was then added and stirred to obtain the compound shown in Formula I, also known as potassium diaryldifluoroborate.

4. The preparation method according to claim 3, characterized in that, The molar ratio of the bromoaromatic hydrocarbon or iodoaromatic hydrocarbon to the n-butyllithium, the monoarylborane dimethyl sulfide complex, the trimethylchlorosilane, the methanol, and the potassium hydrogen fluoride is 1:1-1.2:1-1.2:1-2:3-6:1-1.5; The stirring time after the addition of n-butyllithium is completed is 0.5 to 2 hours; The ether solution of the monoarylborane dimethyl sulfide complex was added and stirred for 1 to 3 hours; The trimethylchlorosilane was added and stirred for 1 to 2 hours; The methanol is added and stirred for 1 to 2 hours; The potassium hydrogen fluoride was added and stirred for 12 to 24 hours; The inert atmosphere is a nitrogen atmosphere.

5. The preparation method according to claim 3 or 4, characterized in that, The treatment process after adding the potassium hydrogen fluoride and stirring the reaction is as follows: filter, remove the solvent and slurry with dichloromethane petroleum ether at a volume ratio of 1:1, filter, and dry the filter cake at 60-80°C for 2-5 hours.

6. A method for preparing the compound of formula II as described in claim 2, comprising the following steps: in the inert atmosphere, stirring and dropwise adding an ether solution of isopropyl magnesium chloride to a brominated aromatic hydrocarbon or an iodoaromatic hydrocarbon, and continuing to stir the reaction after the addition is complete to obtain a mixed solution; In the inert atmosphere, the mixed solution is mixed and stirred with an ether suspension of the compound of formula I as described in claim 1; the solvent is removed from the mixture, the residue is dissolved in toluene, and trimethylchlorosilane is added and stirred to obtain the compound of formula II, also known as triarylborane.

7. The preparation method according to claim 6, characterized in that, The molar ratio of the bromoaromatic or iodoaromatic hydrocarbon, isopropyl magnesium chloride, potassium diaryldifluoroborate, and trimethylchlorosilane is 1:1 to 1.1:1 to 1.1:1 to 3. The stirring time after adding the isopropyl magnesium chloride is 1 to 3 hours; The stirring time after adding the potassium diaryl difluoroborate is 12 to 24 hours.

8. The preparation method according to claim 6 or 7, characterized in that, The post-treatment after the reaction of the added trimethylchlorosilane is complete is as follows: remove the solvent by vacuum distillation, add n-hexane and ultrasonically break up the blocky residue, transfer to a glove box for filtration, remove the solvent by vacuum distillation, recrystallize the residue with n-hexane at -20°C, filter the crystals and wash with n-hexane and air dry.

9. The use of the compound of formula II as claimed in claim 2 as a hindered Lewis acid-base pair catalyst in hydrogenation reactions.

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