Chiral oxazoline imine pyridine functionalized porous organic polymers and preparation and application thereof

Abstract

The application discloses a chiral oxazoline imine pyridine functionalized porous organic polymer and a preparation and application thereof; first, a styryl functionalized OIP monomer (VOIP) is designed and synthesized, and the VOIP, styrene and divinylbenzene are subjected to free radical polymerization under the initiation of azobisisobutyronitrile at a certain proportion to obtain a series of porous organic polymers (POP-OIP); the POP-OIP is used as a ligand to be coordinated with CoCl2 on line to obtain a corresponding POP-OIP-CoCl2 complex, and then the NaBHEt3 is used as an activator to be used for catalyzing an asymmetric borohydration reaction of 1,1-disubstituted olefin and pinacol borane; the heterogeneous catalyst system developed by the application has high catalytic activity, is easy to separate and recycle, and can be recycled, and has a good practical application prospect.

Description

Technical Field

[0001] This invention relates to a chiral oxazoline imine pyridine-functionalized porous organic polymer (POP-OIP) and its preparation method, as well as its application as a multiphase chiral ligand in Co-catalyzed asymmetric hydroboration of olefins, specifically involving the design, preparation and catalytic application of POP-OIP. Background Technology

[0002] Chiral organoboroesters are an important class of synthetic intermediates, whose carbon-boron bonds can be stereoselectively transformed into carbon-carbon, carbon-oxygen, carbon-nitrogen, and carbon-hydrogen bonds, thus yielding many chiral molecules with practical applications. Transition metal-catalyzed asymmetric hydroboration of alkenes is the main route for preparing chiral organoboroesters, and many transition metal (Rh, Ir, Cu, Co, Fe, etc.) chiral catalyst systems have been developed. Among them, the cobalt-chiral oxazoline imine pyridine (OIP-Co) developed in 2014 by Professor Huang Zheng's group at the Shanghai Institute of Organic Chemistry and Professor Lu Zhan's group at Zhejiang University is one of the most efficient catalyst systems. This catalyst system not only uses the inexpensive 3d transition metal Co as a catalyst but also exhibits excellent chiral recognition of 1,1-disubstituted alkenes, achieving excellent enantioselectivity (up to 99% ee value) and regioselectivity (anti-Markovnikov addition products) for hydroboration. The two reported chiral catalyst systems differ slightly. Huang Zheng's group reported the OIP methyl cobalt complex OIP-CoCH3 (J. Am. Chem. Soc., 2014, 136, 15501-15504), with the reaction carried out in THF medium. Lu Zhan's group reported the more stable OIP-CoCl2 complex, with OIP-CoCl2 as a pre-catalyst. In the reaction, sodium triethylborohydride is added for in-situ activation to generate active Co-H species (Org. Chem. Front., 2014, 1, 1306-1309), and the reaction is carried out in solvent-free or toluene medium.

[0003]

[0004] Although OIP-CoCH3 and OIP-CoCl2 / NaBHEt3 exhibit excellent catalytic activity in the asymmetric hydroboration of olefins, the reactions are carried out under homogeneous conditions, making catalyst recovery and reuse impossible. While Co is relatively inexpensive, the chiral ligand OIP requires a multi-step synthetic process, resulting in high preparation costs.

[0005] To overcome the aforementioned limitations, this invention designs and prepares an OIP-functionalized porous organic polymer (POP-OIP), which is then used as a chiral solid ligand to coordinate in-line with CoCl2 for the catalytic asymmetric hydroboration of olefins. Since the catalyst is insoluble in the reaction medium, the reaction proceeds under heterogeneous conditions. After the reaction, the catalyst can be separated from the product and recovered by simple centrifugation or filtration. The recovered catalyst can be reused multiple times while maintaining its catalytic activity. This not only significantly reduces production costs but also simplifies the post-processing and reduces waste emissions. Summary of the Invention

[0006] The present invention aims to provide a novel chiral oxazoline imine pyridine-functionalized porous organic polymer (POP-OIP) and its preparation method, as well as its application in Co-catalyzed asymmetric hydroboration of olefins.

[0007] This invention first designs and synthesizes a styrene-functionalized OIP monomer (VOIP), and then performs free radical polymerization of VOIP, styrene (ST), and divinylbenzene (DVB) in a certain ratio under the initiation of azobisisobutyronitrile (AIBN) to obtain a series of porous organic polymers (POP-OIP). Using POP-OIP as a ligand, it undergoes online coordination with CoCl2 to obtain the corresponding POP-OIP-CoCl2 complex. Then, using NaBHEt3 as an activator, it is used to catalyze the asymmetric hydroboration reaction of 1,1-disubstituted olefins with pinacol borane.

[0008] This heterogeneous catalyst system exhibits comparable catalytic activity to the homogeneous catalysts reported in the literature, and the catalyst is easily separated and recovered. The recovered catalyst can be recycled more than 10 times while still maintaining good catalytic activity.

[0009] The technical solution of the present invention is as follows:

[0010] A chiral oxazoline imine pyridine-functionalized porous organic polymer, denoted as POP-OIP, has the structural formula shown in Formula VIII:

[0011]

[0012] In formula VIII, x:y:z = 1:0~5:10~15, preferably x:y:z = 1:0:15, x:y:z = 1:2:13, x:y:z = 1:4:12 or x:y:z = 1:5:10;

[0013] "*" indicates a connection point.

[0014] A method for preparing a chiral oxazoline imine pyridine-functionalized porous organic polymer (POP-OIP) as shown in Formula VIII, wherein the method comprises:

[0015] Under a N2 atmosphere, the VOIP monomer, styrene, divinylbenzene, azobisisobutyronitrile and organic solvent shown in Formula VII are mixed evenly and polymerized at 60-100°C (preferably 80°C) for 24 hours. After post-treatment, POP-OIP shown in Formula VIII is obtained.

[0016]

[0017] The molar ratio of VOIP monomer, styrene and divinylbenzene is 1:0~5:10~15;

[0018] The mass ratio of azobisisobutyronitrile to VOIP monomer is 0.1–0.2:1, preferably 0.12:1;

[0019] The organic solvent is toluene, and the mass ratio of toluene to VOIP monomer is 6-9:1, preferably 7.5:1;

[0020] The specific post-processing method is as follows: after the reaction is completed, cool to room temperature, wash the obtained block solid with tetrahydrofuran using ultrasound, and dry under vacuum at 60°C to obtain POP-OIP as shown in Formula VIII.

[0021] The POP-OIP shown in Formula VIII of this invention can be used as a chiral solid ligand in the Co-catalyzed asymmetric hydroboration reaction of 1,1-disubstituted olefins with pinacol borane.

[0022] In this invention, the preparation method of the 4-styrene-functionalized chiral oxazoline imine pyridine monomer (VOIP monomer) represented by Formula VII is as follows:

[0023] (1) Mix methyl 4-bromopyridine-2-carboxylate, pyruvic acid, silver nitrate, sodium persulfate and sulfuric acid aqueous solution as shown in Formula I, stir at room temperature for 8-12 h, and then after post-treatment, to obtain the intermediate methyl 4-bromo-6-acetylpyridine-2-carboxylate as shown in Formula II.

[0024]

[0025] In step (1), the molar ratio of raw material I, pyruvic acid, silver nitrate and sodium persulfate is 1:1.0-3.0:0.05-0.2:1.0-3.0, preferably 1:2.0:0.1:2.0;

[0026] The concentration of the sulfuric acid aqueous solution is 0.2-0.6 mol / L, preferably 0.4 mol / L;

[0027] The specific post-processing method is as follows: After the reaction is completed, the insoluble matter is removed by filtration, the filtrate is extracted with dichloromethane, the organic layers are combined, dried with anhydrous sodium sulfate, filtered, the solvent is recovered by vacuum rotary evaporation, and the residue is recrystallized with ethanol to obtain intermediate II;

[0028] (2) Intermediate II, sodium hydroxide and organic solvent A are mixed and stirred at room temperature for 2-4 h (preferably 3 h). Then the pH is adjusted to 1 with hydrochloric acid aqueous solution and then post-treated to obtain intermediate 4-bromo-6-acetylpyridine-2-carboxylic acid as shown in Formula III.

[0029]

[0030] In step (2), the molar ratio of intermediate II to sodium hydroxide is 1:1.0-3.0, preferably 1:2.0;

[0031] Organic solvent A is methanol;

[0032] The concentration of the hydrochloric acid aqueous solution is 6 mol / L;

[0033] The specific post-processing method is as follows: the reaction solution is extracted with ethyl acetate, the organic layer is dried with anhydrous sodium sulfate, filtered, and the solvent is recovered by vacuum rotary evaporation to obtain intermediate III (this intermediate does not require further purification and can be used directly in the next step of the reaction);

[0034] (3) Dissolve intermediate III, oxalyl chloride, and catalyst in organic solvent B and react at room temperature for 4-8 h (preferably 6 h). Recover the solvent and oxalyl chloride by vacuum rotary evaporation to obtain acyl chloride derivative. Then dissolve acyl chloride derivative, L-valine, and triethylamine in organic solvent C and react at room temperature for 1-3 h (preferably 2 h). After post-treatment, the reaction solution is used to obtain intermediate (S)-N-(1-isopropyl-2-hydroxy)-(4-bromo-6-formyl)pyridine-2-carboxamide as shown in formula IV.

[0035]

[0036] In step (3), the molar ratio of intermediate III to oxalyl chloride is 1:1.0-3.0, preferably 1:2.0;

[0037] The catalyst is N,N-dimethylformamide;

[0038] The molar ratio of acyl chloride derivative, L-valine, and triethylamine is 1:1.0-1.5:1.0-3.0, preferably 1:1.1:2.0;

[0039] Organic solvent B and organic solvent C are both dichloromethane;

[0040] The specific post-processing method is as follows: the reaction solution is washed sequentially with 5% hydrochloric acid aqueous solution and 5% sodium bicarbonate aqueous solution, the organic phase is dried with anhydrous sodium sulfate, filtered, the solvent is recovered by vacuum rotary evaporation, and the residue is purified by column chromatography to obtain intermediate IV;

[0041] (4) Dissolve intermediate IV, 2,6-diisopropylaniline, and p-toluenesulfonic acid monohydrate in organic solvent D, heat to reflux, and dehydrate for 18-30 h (preferably 25 h). Then, the reaction solution is post-treated to obtain intermediate (S,E)-N-(1-isopropyl-2-hydroxy)-(4-bromo-6-(1-(2,6-diisopropylphenyl)imino)ethylpyridine-2-carboxamide as shown in formula V.

[0042]

[0043] In step (4), the molar ratio of intermediate IV, 2,6-diisopropylaniline and p-toluenesulfonic acid monohydrate is 1:1.0-2.0:0.05-1.0, preferably 1:1.5:0.08;

[0044] Organic solvent D is toluene;

[0045] The specific post-processing method is as follows: After the reaction is completed, the solvent is recovered by vacuum rotary evaporation of the reaction solution to obtain an oily substance, which is dissolved in dichloromethane, washed with saturated sodium bicarbonate aqueous solution, dried with anhydrous sodium sulfate, filtered, and the solvent is recovered by vacuum rotary evaporation. The residue is purified by column chromatography to obtain intermediate V.

[0046] (5) Under N2 atmosphere, intermediate V is dissolved in organic solvent E, cooled to -20℃, and then diethylaminosulfur trifluoride (DAST) is added dropwise. The reaction is carried out for 20-60 min (preferably 30 min). The reaction solution is then post-treated to obtain intermediate (S,E)-N-(1-(4-bromo-6-(4-isopropyl-4,5-dihydrooxazol-2-yl)pyridin-2-yl)ethylene)-2,6-diisopropylaniline as shown in Formula VI.

[0047]

[0048] In step (5), the molar ratio of intermediate V to diethylaminosulfur trifluoride is 1:1-4, preferably 1:2;

[0049] Organic solvent E is dichloromethane;

[0050] The specific post-processing method is as follows: After the reaction is completed, saturated sodium bicarbonate aqueous solution is added to the reaction solution to quench the reaction, the organic layer is separated, the aqueous layer is extracted with dichloromethane, the organic layers are combined, dried with anhydrous sodium sulfate, filtered, the solvent is recovered by vacuum rotary evaporation under reduced pressure, and the residue is purified by column chromatography to obtain intermediate VI.

[0051] (6) Under N2 atmosphere, intermediate VI, 4-vinylphenylboronic acid, palladium acetate, benzyl diadamantylphosphine (Ad2BnP) and potassium carbonate are mixed in solvent F, heated to 70°C, and stirred for 8-12 h (preferably 10 h). After post-treatment, (S,E)-N-(1-(4-(4-vinyl)phenyl-6-(4-isopropyl-4,5-dihydrooxazol-2-yl)pyridin-2-yl)ethylene)-2,6-diisopropylaniline (VOIP monomer) as shown in formula VII are obtained.

[0052]

[0053] In step (6), the molar ratio of intermediate VI, 4-vinylphenylboronic acid, palladium acetate, benzyldiadamantylphosphine and potassium carbonate is 1:1.0-3.0:0.02-0.05:0.02-0.05:1.0-2.0, preferably 1:1.5:0.03:0.04:1.5;

[0054] Solvent F is a mixture of toluene and water, with a toluene:water ratio of 20-40:1 (volume ratio), preferably 30:1;

[0055] The specific post-processing method is as follows: After the reaction is completed, diatomaceous earth is added to the reaction solution, stirred for 30 min, filtered, the filtrate is extracted with dichloromethane, the organic phase is dried with anhydrous sodium sulfate, filtered, the solvent is recovered by vacuum rotary evaporation, and the residue is purified by column chromatography to obtain the VOIP monomer shown in Formula VII.

[0056] In the above preparation method, organic solvents A to E and solvent F have no special meaning. They are simply labeled A to F to distinguish the solvents used in different operation steps.

[0057] The synthetic route for the chiral oxazoline imine pyridine-functionalized porous organic polymer (POP-OIP) involved in this invention is as follows:

[0058]

[0059] Compared with the prior art, the beneficial effects of the present invention are specifically reflected in:

[0060] A novel chiral oxazoline imine pyridine-functionalized porous organic polymer was designed and developed. This organic polymer serves as a chiral solid ligand for the Co-catalyzed asymmetric hydroboration reaction of 1,1-disubstituted olefins with pinacol borane. The developed heterogeneous catalyst system exhibits comparable catalytic activity to the homogeneous catalysts reported in the literature. Furthermore, the catalyst is easily separated and recovered, and the recovered catalyst can be recycled more than 10 times. This not only significantly reduces the preparation cost of chiral organoboroesters but also simplifies the post-processing and reduces waste, demonstrating promising prospects for practical applications. Attached Figure Description

[0061] Figure 1 : Aggregate single-unit VoIP 1 H NMR spectrum (500MHz).

[0062] Figure 2 : Aggregate single-unit VoIP 13 C NMR spectrum (125MHz).

[0063] Figure 3 N2 adsorption-desorption isotherms of polymers POP-OIP-1, 2, 3, and 4.

[0064] Figure 4 Pore ​​size distribution diagrams of polymers POP-OIP-1, 2, 3, and 4.

[0065] Figure 5 Physical images of polymers POP-OIP-1, 2, 3, and 4.

[0066] Figure 6 Solid state of polymer POP-OIP-3 13 C NMR spectrum (100MHz, rotation speed 8000Hz).

[0067] Figure 7 IR chromatograms of polymer POP-OIP-3 and monomer VOIP.

[0068] Figure 8 CD diagrams of polymers POP-OIP-3 and POP-OIP(R)-3.

[0069] Figure 9 TGA diagrams of polymer POP-OIP-3 and monomer VOIP.

[0070] Figure 10 SEM image of polymer POP-OIP-3.

[0071] Figure 11 TEM image of polymer POP-OIP-3.

[0072] Figure 12 The result of continuously cycling the catalyst system POP-OIP-3-Co 10 times. Detailed Implementation

[0073] The present invention is further described below through specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0074] Example 1: Preparation of styrene-functionalized chiral oxazoline imine pyridine ligand (VOIP)

[0075] Preparation of Intermediate II: In a 1000 mL round-bottom flask, methyl 4-bromopyridinecarboxylate I (10.8 g, 50 mmol) and 0.4 mol / L sulfuric acid aqueous solution were added sequentially. After complete dissolution, pyruvic acid (8.8 g, 100 mmol) and silver nitrate (0.85 g, 5 mmol) were added, and the reaction solution was cooled to 0 °C. Sodium persulfate (23.8 g, 100 mmol) was added slowly in portions under vigorous stirring. After the addition was complete, the reaction solution was brought to room temperature and stirred overnight. After the reaction was complete, the insoluble matter was removed by filtration, and the filtrate was extracted with 30 mL × 3 dichloromethane. The organic layers were combined, dried over anhydrous sodium sulfate, filtered, and the solvent was recovered by rotary evaporation under vacuum. The residue was recrystallized from ethanol to give 8.8 g of white solid, yield 68%. 1 H NMR (500MHz, CDCl3) δ8.40 (d, J = 1.5 Hz, 1H), 8.33 (d, J = 1.6 Hz, 1H), 4.02 (s, 3H), 2.76 (s, 3H) ppm; 13 C NMR (125MHz, CDCl3) δ198.4,164.2,154.3,148.7,135.1,131.5,128.0,53.4,25.8ppm.

[0076] Preparation of Intermediate III: Intermediate II (6.5 g, 25 mmol), sodium hydroxide aqueous solution (2.10 g dissolved in 5 mL of water, 50 mmol), and 250 mL of methanol were added sequentially to a 500 mL round-bottom flask. The mixture was stirred at room temperature for 3 hours. After the reaction was completed, the solvent was recovered by rotary evaporation under vacuum. The residue was dissolved in a small amount of water, and the pH of the reaction solution was adjusted to 1 with 6 mol / L hydrochloric acid. The mixture was then extracted with 30 mL × 3 dichloromethane. The organic phases were combined, dried over anhydrous sodium sulfate, filtered, and the solvent was recovered by rotary evaporation under vacuum to obtain 6.0 g of white solid, with a yield of 99%. This intermediate did not require further purification and could be used directly in the next reaction. 1 H NMR (500MHz, CDCl3) δ8.55 (d, J = 1.8Hz, 1H), 8.44 (d, J = 1.8Hz, 1H), 2.77 (s, 3H) ppm; 13 C NMR (125MHz, CDCl3) δ196.7,163.2,153.0,146.8,136.9,130.9,129.3,25.9ppm.

[0077] Preparation of Intermediate IV: Intermediate III (4.90 g, 20 mmol), DMF (2 drops), and 100 mL of dichloromethane were added to a 500 mL round-bottom flask and dissolved completely. Oxaloyl chloride (3.2 mL, 38.0 mmol) was then slowly added dropwise, and the mixture was stirred at room temperature for 6 hours. After the reaction was complete, the solvent was removed by rotary evaporation under reduced pressure to obtain the acylated product, which was dissolved in 15 mL of dichloromethane. In another 500 mL three-necked flask, L-valine (2.20 g, 21 mmol), triethylamine (5.6 mL, 38 mmol), and 200 mL of dichloromethane were added. The mixture was cooled to 0 °C, and under nitrogen protection, a dichloromethane solution of the acylated product was slowly added dropwise over 30 min. After the addition was complete, the reaction mixture was brought to room temperature and stirred for 3 hours. After the reaction was completed, the reaction solution was washed successively with 5% hydrochloric acid aqueous solution and 5% sodium bicarbonate aqueous solution. The organic layer was dried with anhydrous sodium sulfate, filtered, and the solvent was recovered by vacuum rotary evaporation. The residue was subjected to column chromatography to obtain 5.5 g of white solid, with a yield of 84%. 1 H NMR (500MHz, CDCl3) δ8.37(m,1H),8.30-8.08(m,2H),4.00-3.88(m,1H),3.86-3.67(m,2H),3.09(t,J= 5.3Hz,1H),2.71(d,J=3.1Hz,3H),2.12-1.96(m,1H),1.02(d,J=6.9Hz,3H),1.00(d,J=6.9Hz,3H)ppm; 13 C NMR (125MHz, CDCl3) δ197.4,163.1,153.1,150.7,147.6,136.1,129.1,127.5,126.1,124.4,63.7,57.5,29.3,25.7,19.8,18.5ppm.

[0078] Preparation of intermediate V: In a 100 mL two-necked flask, IV (3.90 g, 12 mmol), 2,6-diisopropylaniline (3.20 g, 18 mmol), p-toluenesulfonic acid monohydrate (182 mg, 0.96 mmol), and 50 mL of toluene were added sequentially, and the mixture was stirred under reflux for 24 hours. After the reaction was complete, the solvent was recovered by rotary evaporation under vacuum. The residual oily substance was dissolved in a small amount of dichloromethane, washed with saturated sodium bicarbonate solution, dried over anhydrous sodium sulfate, filtered, and the solvent was recovered by rotary evaporation under vacuum. The residue was purified by column chromatography to give 4.50 g of a yellow solid, with a yield of 77%. 1H NMR (500MHz, CDCl3) δ8.70-8.40(m,1H),8.28-8.19(m,1H),7.18(d,J=7.1Hz,2H),7.12(m,1H),4.06-3.92(m,1H),3.87-3.73(m,2H), 3.17(s,1H),2.71-2.65(m,2H),2.21(d,J=3.7Hz,3H),2.1-2.0(m,1H),1.51(m,12H),1.05(d,J=6.8Hz,3H),1.02(d,J=6.9Hz,3H)ppm; 13 C NMR (125MHz, CDCl3) δ164.9,163.8,156.1,150.3,149.9,146.8,145.8,135.7,127.0 ,124.2,123.9,123.2,64.0,57.5,29.3,28.4,27.0,23.3,23.0,19.8,18.5,17.1ppm.

[0079] Preparation of intermediate VI: Under a nitrogen atmosphere, intermediate V (1.90 g, 4.0 mmol) and 20 mL of dichloromethane were added to a 50 mL jacketed flask. The temperature was lowered to -20 °C, and DAST (1.0 mL, 8.0 mmol) was added dropwise. After the addition was complete, the reaction was stirred for 30 minutes. After the reaction was completed, the reaction was quenched with saturated sodium bicarbonate aqueous solution. The organic layer was separated, and the aqueous layer was extracted with 10 mL of dichloromethane. The organic layers were combined, dried over anhydrous sodium sulfate, filtered, and the solvent was recovered by rotary evaporation under vacuum. The residue was purified by column chromatography to give 1.60 g of yellow solid, with a yield of 85%. 1 H NMR(500MHz, CDCl3)δ8.5(m,1H),8.29(m,1H),7.17(d,J=7.3Hz,2H),7.11(m,1H),4.56(t,J=8.9Hz,1H),4.26(t,J=8.3Hz,1H),4.23-4 .16(m,1H),2.73-2.67(m,2H),2.27(d,J=3.7Hz,3H),1.95-1.88(m,1H),1.14(m,12H),1.08(d,J=6.7Hz,3H),0.97(d,J=6.8Hz,3H)ppm; 13C NMR (125MHz, CDCl3) δ166.0,161.9,157.6,157.2,147.5,147.3,146.0,145.4,135.8,134.0, 128.5,126.3,125.6,124.0,123.2,73.1,71.2,32.3,28.4,23.4,23.0,19.2,18.4,17.4ppm.

[0080] Preparation of VII (VOIP monomer): Under a nitrogen atmosphere, intermediate VI (470 mg, 1.0 mmol), 4-vinylphenylboronic acid (220 mg, 1.5 mmol), palladium acetate (11 mg, 0.05 mmol), benzyldiadamantylphosphine (21 mg, 0.054 mmol), potassium carbonate (310 mg, 2.2 mmol), and 10 mL of solvent (toluene:water = 30:1) were added sequentially to a 50 mL Young tube. The mixture was heated to 70 °C and stirred for 6 hours. After the reaction was complete, diatomaceous earth and anhydrous sodium sulfate were added to the reaction solution, and the mixture was stirred for 1 hour. The mixture was then filtered, and the solvent was recovered by rotary evaporation under vacuum. The residue was purified by column chromatography to give 400 mg of a yellow solid, with a yield of 81%. 1 H NMR (500MHz, CDCl3) δ8.79(d,J=1.3Hz,1H),8.48(d,J=1.4Hz,1H),7.81(d,J=7.0Hz,2H),7.56(d,J=7.0Hz ,2H),7.19(d,J=6.4Hz,2H),7.12(t,J=6.7Hz,1H),6.78(dd,J=9.1,14.7Hz,1H),5.86(d,J=14.7Hz,1H),5. 35(d,J=9.2Hz,1H),4.59(dd,J=6.9,8.0Hz,1H),4.30(t,J=6.9Hz,1H),4.27-4.19(m,1H),2.81-2.77(m,2 H),2.36(s,3H),1.97(m,1H),1.17(m,12H),1.14(m,12H),1.12(d,J=5.7Hz,3H),1.00(d,J=5.6Hz,3H)ppm; 13C NMR (125MHz, CDCl3) δ167.0,162.9,156.9,149.0,146.9,146.4,138.9,136.8,136.1,135.8,127.5,127.0,123 .8,123.1,123.0,120.5,115.3,73.1,71.0,33.0,28.3,23.4,23.1,19.3,18.3,17.6ppm; HRMS(EI-TOF)m / z:[M + ]calculated for C 33 H 39 N3O493.3124,found 493.3126;[α]D 20 -51.7 (c=0.5, CHCl3).

[0081] Example 2: Preparation of chiral oxazoline imine pyridine-functionalized porous organic polymer POP-OIP

[0082] Preparation of POP-OIP-X: Under a nitrogen atmosphere, monomers VOIP, styrene, divinylbenzene, azobisisobutyronitrile, and toluene were added sequentially to a 15 mL Young tube. The mixture was stirred at room temperature for 1 hour to ensure homogeneity, and then allowed to stand at 80°C for 24 hours for polymerization. After the reaction was complete, the block polymer was removed from the Young tube and ultrasonically washed three times with tetrahydrofuran. It was then vacuum dried at 60°C for 12 hours and ground to obtain a pale yellow powder.

[0083] The molar ratios of VOIP, styrene, and divinylbenzene are 1:0:15, 1:2:13, 1:4:12, and 1:5:10, and the corresponding polymers are labeled as POP-OIP-1, POP-OIP-2, POP-OIP-3, and POP-OIP-4, respectively.

[0084]

[0085] Furthermore, the nitrogen content of the prepared polymer POP-OIP-X (X = 1, 2, 3, 4) was analyzed to obtain the loading of OIP; the specific surface area, pore volume and pore size of POP-OIP-X were measured by nitrogen isothermal adsorption-desorption experiment, and the specific data are shown in Table 1.

[0086] Table 1. Hole structure properties and OIP loading of POP-OIP-X

[0087]

[0088]

[0089] Furthermore, a more detailed analysis was conducted on the optimal chiral polymer POP-OIP-3. 13 Analysis was performed using C NMR, IR, CD, TGA, SEM, and TEM. Specific spectra are shown in the attached figures.

[0090] Example 3: Asymmetric hydroboration of 1,1-disubstituted olefins with pinacol borane catalyzed by POP-OIP-3 / CoCl2 / NaBHEt3

[0091] Under nitrogen protection, POP-OIP-3 (32 mg, 2 mol%), CoCl2 (0.65 mg, 1 mol%), and 2 mL of anhydrous THF were added sequentially to a 15 mL Young tube. After stirring for 1 hour, the solid color changed from yellow to dark green, and the solution color changed from blue to colorless. Then, 1,1-disubstituted olefin (0.5 mmol), HBpin (0.5 mmol), and NaBHEt3 (10 μL, 0.01 mmol) were added sequentially. After the addition was complete, the reaction mixture was stirred at room temperature for 2–12 hours, and the reaction process was monitored by GC. After the reaction was complete, the mixture was centrifuged, the supernatant was collected, and the solid was washed with 2 mL × 3 mL of THF. The organic phases were combined, the solvent was recovered by rotary evaporation under reduced pressure, and the residue was purified by column chromatography to obtain the corresponding hydroboration addition product, and the yield was calculated. The structure of the product was determined by [further details needed]. 1 H NMR and 13 The results were confirmed by CNMR characterization, and the ee value was determined by HPLC using a chiral column Daicel Chiralpak OD-H (0.46 x 25 cm). The specific experimental results are shown in Table 2.

[0092] Table 2. Asymmetric hydroboration of 1,1-disubstituted olefins with HBpin catalyzed by POP-OIP-3 / CoCl2 / NaBHEt3.

[0093]

[0094]

[0095] Characterization data of the preparation products in Examples 3-20:

[0096] Example 3:

[0097] (S)-(+)-4,4,5,5-Tetramethyl-2-(2-phenylpropyl)-1,3,2-dioxocyclopentaborane, colorless oily liquid; 1 H NMR (500MHz, CDCl3) δ7.30-7.24(m,4H),7.19-7.14(m,1H),3.09-3.01(m,1H),1.29(d,J=7.0Hz,3H),1.19-1.15(m,14H)ppm.13 C NMR (125MHz, CDCl3) δ149.3,128.3,126.7,125.8,83.1,35.9,25.0,24.9,24.8ppm; Optical Rotation:[α]D 20 +19.9 (c=0.5, CHCl3).

[0098] Example 4:

[0099] (S)-(+)-4,4,5,5-Tetramethyl-2-(2-(p-tolyl)propyl)-1,3,2-dioxocyclopentaborane, colorless oily liquid; 1 H NMR (500MHz, CDCl3) δ7.13(d,J=8.1Hz,2H),7.08(d,J=7.9Hz,2H),3.10-2.89( m,1H),2.31(s,3H),1.26(d,J=6.9Hz,3H),1.18(s,12H),1.16-1.15(m,2H)ppm. 13 C NMR (125MHz, CDCl3) δ146.4,135.1,129.0,126.6,83.1,35.5,25.0,24.9,24.8,21.1ppm; Optical Rotation:[α]D 20 +24.5 (c=0.5, CHCl3).

[0100] Example 5:

[0101] (S)-(+)-4,4,5,5-Tetramethyl-2-(2-(m-tolyl)propyl)-1,3,2-dioxocyclopentaborane, colorless oily liquid; 1 H NMR(500MHz, CDCl3)δ7.16(t,J=7.5Hz,1H),7.08-7.02(m,2H),6.97(d,J=7.5Hz,1H), 3.06-2.93(m,1H),2.32(s,3H),1.27(d,J=7.0Hz,3H),1.17(s,12H),1.14(m,2H)ppm. 13 C NMR (125MHz, CDCl3) δ149.3,137.7,128.2,127.6,126.5,123.7,83.1,35.8,24.9,24.8,21.6ppm; Optical Rotation:[α]D 21 +18.9 (c=0.5, CHCl3).

[0102] Example 6:

[0103] (S)-(+)-4,4,5,5-Tetramethyl-2-(2-(o-tolyl)propyl)-1,3,2-dioxocyclopentaborane, colorless oily liquid; 1 H NMR(500MHz, CDCl3)δ7.24(d,J=7.7Hz,1H),7.15-7.05(m,1H),7.09(d,J=6.7Hz,1H),7.06-7.00(m,1H) ,3.39-3.18(m,1H),2.37(s,3H),1.23(d,J=6.9Hz,3H),1.18-1.15(m,1H),1.13(s,6H),1.11(s,6H)ppm. 13 C NMR (125MHz, CDCl3) δ147.3,135.0,130.1,126.2,125.5,125.3,83.0,30.8,24.8,24.7,24.4,19.7ppm; Optical Rotation:[α]D 21 +9.8 (c=0.5, CHCl3).

[0104] Example 7:

[0105] (S)-(+)-2-(2-(4-tert-butylphenyl)propyl)-4,4,5,5-tetramethyl-1,3,2-dioxocyclopentaborane, colorless oily liquid; 1 H NMR (500MHz, CDCl3) δ7.30 (d, J = 6.9 Hz, 2H), 7.18 (d, J = 6.9 Hz, 2H), 3.09-2.92 (m, 1H), 1.34-1.27 (m, 13H), 1.17 (m, 14H) ppm. 13 C NMR (125MHz, CDCl3) δ148.5,146.2,126.4,125.1,83.0,35.4,34.4,31.6,24.9,24.8ppm; Optical Rotation:[α]D 21 +23.3 (c=0.5, CHCl3).

[0106] Example 8:

[0107] (S)-(+)-2-(2-(4-fluorophenyl)propyl)-4,4,5,5-tetramethyl-1,3,2-dioxocyclopentaborane, colorless oily liquid; 1H NMR (500MHz, CDCl3) δ7.21-7.14(m,2H),6.97-6.90(m,2H),3.15-2.86(m,1H),1.24(d,J=6.9Hz,3H),1.15(d,J=1.6Hz,12H),1.12(d,J=7.9Hz,2H)ppm. 13 C NMR (125MHz, CDCl3) δ161.2 (d, J = 242.8Hz), 144.9 (d, J = 3.1Hz), 128.1 (d, J = 7.8Hz), 115.0 (d, J = 21.1Hz), 83.2, 35.3, 25.3, 24.9, 24.8ppm; Optical Rotation:[α]D 21 +19.3 (c=0.5, CHCl3).

[0108] Example 9:

[0109] (S)-(+)-2-(2-(4-chlorophenyl)propyl)-4,4,5,5-tetramethyl-1,3,2-dioxocyclopentaborane, colorless oily liquid; 1 H NMR (500MHz, CDCl3) δ7.22(d,J=8.5Hz,2H),7.16(d,J=8.4Hz,2H),3.11-2.91( m,1H),1.24(d,J=7.0Hz,3H),1.16(d,J=2.2Hz,12H),1.12(d,J=7.9Hz,2H)ppm. 13 C NMR (125MHz, CDCl3) δ147.8,131.3,128.4,128.2,83.2,35.4,25.0,24.9,24.8ppm; OpticalRotation:[α]D 21 +23.5 (c=0.5, CHCl3).

[0110] Example 10:

[0111] (S)-(+)-2-(2-(4-bromophenyl)propyl)-4,4,5,5-tetramethyl-1,3,2-dioxocyclopentaborane, colorless oily liquid; 1 H NMR(500MHz, CDCl3) δ7.37(d,J=8.4Hz,2H),7.11(d,J=8.4Hz,2H),3.03-2.95( m,1H),1.24(d,J=6.9Hz,3H),1.16(d,J=2.3Hz,12H),1.11(d,J=8.0Hz,2H)ppm. 13C NMR (125MHz, CDCl3) δ148.3,131.2,128.6,119.4,83.2,35.5,24.9,24.9,24.8ppm; OpticalRotation:[α]D 21 +27.1 (c=0.5, CHCl3).

[0112] Example 11:

[0113] (S)-(+)-4,4,5,5-Tetramethyl-2-(2-(4-(trifluoromethyl)phenyl)propyl)-1,3,2-dioxocyclopentaborane, colorless oily liquid; 1 H NMR (500MHz, CDCl3) δ7.51 (d, J = 8.1Hz, 2H), 7.34 (d, J = 8.2Hz, 2H), 3.14-3.04 (m, 1H), 1.28 (d, J = 6.9Hz, 3H), 1.17-1.12 (m, 14H) ppm. 13 C NMR (125MHz, CDCl3) δ153.4,128.2(q,J=32.0Hz),127.1,125.3(q,J=4.0Hz),124.5(q,J=271.2Hz),83.3,35.9,24.9,24.8,24.7ppm; Optical Rotation:[α]D 21 +20.9 (c=0.5, CHCl3).

[0114] Example 12:

[0115] (S)-(+)-4,4,5,5-Tetramethyl-2-(2-(naphth-2-yl)propyl)-1,3,2-dioxocyclopentaborane, colorless oily liquid; 1 H NMR (500MHz, CDCl3) δ7.81-7.70(m,3H),7.68(s,1H),7.48-7.37(m,3H),3. 29-3.19(m,1H),1.39(d,J=7.0Hz,3H),1.32-1.26(m,2H),1.16(s,12H)ppm. 13 C NMR (125MHz, CDCl3) δ146.8,133.7,132.2,127.9,127.7,127.6,126.0,125.8,125.0,124.5,83.1,36.0,24.9,24.9,24.8ppm; Optical Rotation:[α]D 21 +29.2 (c=0.5, CHCl3).

[0116] Example 13:

[0117] (S)-(+)-2-(2-(6-methoxynaphthyl-2-yl)propyl)-4,4,5,5-tetramethyl-1,3,2-dioxocyclopentaborane, colorless oily liquid; 1 H NMR(500MHz, CDCl3)δ7.68(dd,J=6.0,8.5Hz,2H),7.60(s,1H),7.39(dd,J=1.7,8.5Hz,1H),7.14-7.0 8(m,2H),3.91(s,3H),3.29-3.07(m,1H),1.37(d,J=6.9Hz,3H),1.28-1.23(m,2H),1.15(s,12H)ppm. 13 C NMR (125MHz, CDCl3) δ157.1,144.5,133.1,129.2,126.7,126.4,124.4,118.5,105.7,83.1,55.3,35.8,25.0,24.9,24.8ppm; Optical Rotation:[α]D 21 +32.0 (c=0.5, CHCl3).

[0118] Example 14:

[0119] (S)-(+)-2-(2-(benzo[d][1,3]dioxo-5-yl)propyl)-4,4,5,5-tetramethyl-1,3,2-dioxocyclopentaborane, colorless oily liquid; 1 H NMR (500MHz, CDCl3) δ6.74(d,J=1.4Hz,1H),6.71-6.66(m,2H),5.89(s,2H),3.01-2.91(m,1H),1.23(d,J=6.9Hz,3H),1.17(s, 12H),1.09(dd,J=1.9,7.4Hz,2H),3.91(s,3H),3.29-3.07(m,1H),1.37(d,J=6.9Hz,3H),1.28-1.23(m,2H),1.15(s,12H)ppm. 13 C NMR (125MHz, CDCl3) δ147.5,145.4,143.6,119.4,108.0,107.3,100.7,83.1,35.7,25.2,24.9,24.8ppm; Optical Rotation:[α]D 21 +31.6 (c=0.5, CHCl3).

[0120] Example 15:

[0121] (R)-(+)-4,4,5,5-Tetramethyl-2-(2-phenylbutyl)-1,3,2-dioxocyclopentaborane, colorless oily liquid; 1 H NMR (500MHz, CDCl3) δ7.27-7.23(m,2H),7.21-7.17(m,2H),7.16-7.11(m,1H),2.77-2.7 0(m,1H),1.68-1.55(m,2H),1.24-1.11(m,2H),1.09(s,12H),0.78(t,J=7.4Hz,3H)ppm. 13 C NMR (125MHz, CDCl3) δ147.4,128.1,127.6,125.8,83.0,43.4,32.4,24.8,24.8,12.4ppm; Optical Rotation:[α]D 21 +15.4 (c=0.5, CHCl3).

[0122] Example 16:

[0123] (R)-(+)-4,4,5,5-Tetramethyl-2-(2-phenylpentyl)-1,3,2-dioxocyclopentaborane, colorless oily liquid; 1 H NMR (500MHz, CDCl3) δ7.26-7.22(m,2H),7.21-7.18(m,2H),7.15-7.11(m,1H),2.84(m, 1H),1.57(q,J=7.7Hz,2H),1.23-1.10(m,4H),1.09(s,12H),0.84(t,J=7.3Hz,3H)ppm. 13 C NMR (125MHz, CDCl3) δ147.6,128.1,127.5,125.7,83.0,41.9,41.3,24.7,20.8,14.2ppm; Optical Rotation:[α]D 21 +10.5 (c=0.5, CHCl3).

[0124] Example 17:

[0125] (R)-(-)-2-(2,3-diphenylpropyl)-4,4,5,5-tetramethyl-1,3,2-dioxocyclopentaborane, a colorless oily liquid; 1H NMR (500MHz, CDCl3) δ7.25-7.11(m,8H),7.05(d,J=10Hz,2H),3.15(m,1H),2.94-2.80(m,2H),1.25-1.16(m,2H),1.08(s,6H)ppm. 13 C NMR (125MHz, CDCl3) δ146.6,140.9,129.5,128.1,128.1,127.7,126.0,125.8,83.1,46.3,43.7,24.8,24.7ppm; OpticalRotation:[α]D 21 -41.3 (c=0.5, CHCl3).

[0126] Example 18:

[0127] (R)-(+)-4,4,5,5-Tetramethyl-2-(2-methyl-4-phenylbutyl)-1,3,2-dioxocyclopentaborane, a colorless oily liquid; 1 H NMR (500MHz, CDCl3) δ7.29-7.25(m,2H),7.20-7.15(m,3H),2.68-2.55(m,2H),1.83-1.73(m,1H),1.66-1.46 (m,2H),1.26(s,12H),1.00(d,J=6.6Hz,3H),0.91(dd,J=5.9,15.3Hz,1H),0.73(dd,J=15.2,8.1Hz,1H)ppm. 13 C NMR (125MHz, CDCl3) δ143.3,128.5,128.4,125.6,83.0,41.7,33.9,29.5,25.0,24.9,22.4ppm; Optical Rotation:[α]D 21 +2.1 (c=0.5, CHCl3).

[0128] Example 19:

[0129] (R)-(-)-2-(1,2-diphenylethyl)-4,4,5,5-tetramethyl-1,3,2-dioxocyclopentaborane, a colorless oily liquid; 1H NMR(500MHz, CDCl3)δ7.28(d,J=3.6Hz,4H),7.25-7.21(m,4H),7.19-7.15(m,2H),3.19(dd,J=10.0, 13.5Hz, 1H), 3.00 (dd, J=13.1, 6.9Hz, 1H), 2.72 (dd, J=7.2, 9.9Hz, 1H), 1.14 (s, 6H), 1.13 (s, 6H) ppm. 13 C NMR (125MHz, CDCl3) δ142.7,141.9,129.0,128.5,128.4,128.2,125.9,125.5,83.5,39.0,24.7,24.6ppm; Optical Rotation:[α]D 21 -35.6 (c=0.5, CHCl3).

[0130] Example 20:

[0131] 2-((1S,2S,4S)-bicyclo[2.2.1]heptane-2-yl)-4,4,5,5-tetramethyl-1,3,2-dioxocyclopentaborane, colorless oily liquid; 1 H NMR (500MHz, CDCl3) δ2.26-2.23(m,1H),2.16-2.20(m,1H),1.58-1.43(m,3H),1.37-1.30(m,1H),1.26-1.11(m,16H),0.88-0.85(m,1H)ppm. 13 C NMR (125MHz, CDCl3) δ82.9,38.9,38.3,36.8,32.4,32.3,29.4,24.8ppm; Optical Rotation:[α]D 21 -4.5 (c=0.5, CHCl3).

[0132] Example 21: Asymmetric hydroboration of 1-methyl-1-phenylethylene with pinacol borane catalyzed by POP-OIP-1 / CoCl2 / NaBHEt3

[0133] Replacing POP-OIP-3 with POP-OIP-1 in Example 3, while keeping other conditions unchanged, yielded 109 mg of product (S)-(+)-4,4,5,5-tetramethyl-2-(2-phenylpropyl)-1,3,2-dioxocyclopentaborane, with a yield of 89% and an ee value of 94%.

[0134] Example 22: Asymmetric hydroboration of 1-methyl-1-phenylethylene with pinacol borane catalyzed by POP-OIP-2 / CoCl2 / NaBHEt3

[0135] Replacing POP-OIP-3 with POP-OIP-2 in Example 3, while keeping other conditions unchanged, yielded 116 mg of the product (S)-(+)-4,4,5,5-tetramethyl-2-(2-phenylpropyl)-1,3,2-dioxocyclopentaborane, with a yield of 94% and an ee value of 94%.

[0136] Example 23: Asymmetric hydroboration of 1-methyl-1-phenylethylene with pinacol borane catalyzed by POP-OIP-4 / CoCl2 / NaBHEt3

[0137] Replacing POP-OIP-3 with POP-OIP-4 in Example 3, while keeping other conditions unchanged, yielded 109 mg of product (S)-(+)-4,4,5,5-tetramethyl-2-(2-phenylpropyl)-1,3,2-dioxocyclopentaborane, with a yield of 89% and an ee value of 95%.

[0138] Example 24 Recovery and Recycling of Catalyst POP-OIP-3-Co

[0139] Under nitrogen protection, the POP-OIP-3-Co catalyst, after centrifugation and THF washing, was transferred to a 15 mL Young tube. Then, 1-methyl-1-phenylethylene (59 mg, 0.5 mmol), HBpin (0.5 mmol), and NaBHEt3 (10 μL, 0.01 mmol) were added sequentially. After the addition was complete, the reaction mixture was stirred at room temperature for 2 hours. GC analysis showed that the conversion of 1-methyl-1-phenylethylene was greater than 99%. After the same post-treatment, 118 mg of (S)-(+)-4,4,5,5-tetramethyl-2-(2-phenylpropyl)-1,3,2-dioxane was obtained, with a yield of 96% and an ee value of 96%. Under the same operation, the POP-OIP-3-Co catalyst could be continuously recycled more than 10 times while maintaining high catalytic activity. The results are shown in the attached figure. Figure 12 As shown.

Claims

1. A chiral oxazoline imine pyridine-functionalized porous organic polymer, denoted as POP-OIP, with the structural formula shown in Formula VIII: In equation VIII, x:y:z = 1:0~5:10~15; "*" indicates a connection point.

2. The method for preparing the chiral oxazoline imine pyridine-functionalized porous organic polymer as described in claim 1, characterized in that, The method is as follows: Under a N2 atmosphere, the VOIP monomer shown in Formula VII, styrene, divinylbenzene, azobisisobutyronitrile and organic solvent are mixed evenly and polymerized at 60-100°C for 24 hours. After post-treatment, POP-OIP shown in Formula VIII is obtained. The molar ratio of VOIP monomer, styrene and divinylbenzene is 1:0-5:10-15.

3. The method for preparing the chiral oxazoline imine pyridine-functionalized porous organic polymer as described in claim 2, characterized in that, The mass ratio of azobisisobutyronitrile to VOIP monomer is 0.1–0.2:

1.

4. The method for preparing the chiral oxazoline imine pyridine-functionalized porous organic polymer as described in claim 2, characterized in that, The organic solvent is toluene, and the mass ratio of toluene to VOIP monomer is 6 to 9:

1.

5. The application of the chiral oxazoline imine pyridine-functionalized porous organic polymer as described in claim 1 as a chiral solid ligand in the Co-catalyzed asymmetric hydroboration reaction of 1,1-disubstituted olefins with pinacol borane.

6. A 4-styrene-functionalized chiral oxazoline imine pyridine monomer, namely: VOIP monomer, with the structural formula shown in Formula VII:

7. The method for preparing the 4-styrene-functionalized chiral oxazoline imine pyridine monomer as described in claim 6, characterized in that, Includes the following steps: (1) Mix methyl 4-bromopyridine-2-carboxylate, pyruvic acid, silver nitrate, sodium persulfate and sulfuric acid aqueous solution as shown in Formula I, stir at room temperature for 8-12 h, and then after post-treatment, to obtain the intermediate methyl 4-bromo-6-acetylpyridine-2-carboxylate as shown in Formula II. In step (1), the molar ratio of raw material I, pyruvic acid, silver nitrate and sodium persulfate is 1:1.0-3.0:0.05-0.2:1.0-3.0; The concentration of the sulfuric acid aqueous solution is 0.2-0.6 mol / L; (2) Intermediate II, sodium hydroxide and organic solvent A are mixed and stirred at room temperature for 2-4 hours. Then the pH is adjusted to 1 with hydrochloric acid aqueous solution and then post-treated to obtain intermediate 4-bromo-6-acetylpyridine-2-carboxylic acid as shown in Formula III. In step (2), the molar ratio of intermediate II to sodium hydroxide is 1:1.0-3.0; Organic solvent A is methanol; The concentration of the hydrochloric acid aqueous solution is 6 mol / L; (3) Intermediate III, oxalyl chloride, and catalyst were dissolved in organic solvent B and reacted at room temperature for 4-8 h. The solvent and oxalyl chloride were recovered by vacuum rotary evaporation to obtain the acyl chloride derivative. The acyl chloride derivative, L-valine, and triethylamine were then dissolved in organic solvent C and reacted at room temperature for 1-3 h. The reaction solution was then post-treated to obtain intermediate (S)-N-(1-isopropyl-2-hydroxy)-(4-bromo-6-formyl)pyridine-2-carboxamide as shown in Formula IV. In step (3), the molar ratio of intermediate III to oxaloyl chloride is 1:1.0-3.0; The catalyst is N,N-dimethylformamide; The molar ratio of acyl chloride derivative, L-valine, and triethylamine is 1:1.0-1.5:1.0-3.0; Organic solvent B and organic solvent C are both dichloromethane; (4) Intermediate IV, 2,6-diisopropylaniline and p-toluenesulfonic acid monohydrate were dissolved in organic solvent D, heated to reflux, and dehydrated for 18-30 h. The reaction solution was then post-treated to obtain intermediate (S,E)-N-(1-isopropyl-2-hydroxy)-(4-bromo-6-(1-(2,6-diisopropylphenyl)imino)ethylpyridine-2-carboxamide as shown in formula V. In step (4), the molar ratio of intermediate IV, 2,6-diisopropylaniline and p-toluenesulfonic acid monohydrate is 1:1.0-2.0:0.05-1.0; Organic solvent D is toluene; (5) Under N2 atmosphere, intermediate V was dissolved in organic solvent E, cooled to -20℃, and then diethylamino sulfur trifluoride was added dropwise. The reaction was carried out for 20-60 min. After the reaction solution was post-treated, intermediate (S,E)-N-(1-(4-bromo-6-(4-isopropyl-4,5-dihydrooxazol-2-yl)pyridin-2-yl)ethylene)-2,6-diisopropylaniline was obtained as shown in formula VI. In step (5), the molar ratio of intermediate V to diethylaminosulfur trifluoride is 1:1-4; Organic solvent E is dichloromethane; (6) Under N2 atmosphere, intermediate VI, 4-vinylphenylboronic acid, palladium acetate, benzyldiadamantylphosphine and potassium carbonate are mixed in solvent F, heated to 70℃, and stirred for 8-12 h. After post-treatment, (S,E)-N-(1-(4-(4-vinyl)phenyl-6-(4-isopropyl-4,5-dihydrooxazol-2-yl)pyridin-2-yl)ethylene)-2,6-diisopropylaniline, i.e., VOIP monomer, is obtained; In step (6), the molar ratio of intermediate VI, 4-vinylphenylboronic acid, palladium acetate, benzyldiadamantylphosphine and potassium carbonate is 1:1.0-3.0:0.02-0.05:0.02-0.05:1.0-2.0; Solvent F is a mixture of toluene and water, with a toluene:water ratio of 20-40:1.

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