A method for preparing an alpha-bmida ester compound

Abstract

This invention provides a method for preparing α-BMIDA ester compounds. The method uses α-BMIDA propylene ester and potassium alkyl trifluoroborate as substrates, and generates α-BMIDA esters through intermolecular radical addition-protonation reaction under photocatalytic conditions. This achieves the goal of efficient and versatile synthesis of α-BMIDA esters with different functional groups. The use of α-BMIDA propylene ester as the core reaction unit effectively allows for reaction with various alkyl radicals from different sources or structures, enriching the variety of α-BMIDA esters. Furthermore, the method avoids the use of oxidants and diazo compounds. The yield of most synthesized α-BMIDA ester products is higher than 80%. It has the advantages of mild reaction conditions, simple steps, fast reaction rate, and high yield. The reactants used are readily available, and the catalyst is inexpensive, providing an economical and convenient solution and technical support for the large-scale preparation of α-BMIDA ester compounds.

Description

Technical Field

[0001] This invention belongs to the field of organic synthesis technology, specifically relating to a method for preparing α-BMIDA ester compounds. Background Technology

[0002] Organoboron compounds are widely used synthetic intermediates in organic chemistry, medicinal chemistry, and materials science. Given the rich reactivity of boron and carbonyl functional groups, the synthesis of α-boron carbonyl compounds has attracted considerable attention. Common synthetic methods include: transition metal or enzyme-catalyzed boron-hydrogen insertion reactions of boranes with diazo compounds, sulfoxide ylides, or alkyne derivatives; radical addition reactions of boranes with α,β-unsaturated carbonyl compounds and alkenyl trifluoromethanesulfonates; and oxidation or hydrolysis reactions of alkyne or propargyl borate esters. Among these compounds, N-methyliminodiacetylborate (MIDA borate) is particularly unique; the unique properties of the MIDA ligand allow it to transfer the boron center from the electron-deficient sp... 2 The hybridization state transitions to an electron-rich sp state. 3 Due to its hybrid state, MIDA borate esters possess characteristics such as coordination saturation, monomeric structure, chromatographic and air stability, and high crystallinity.

[0003]

[0004] MIDA boronic esters, as a special and more stable class of boronic ester building blocks, have been widely used in various fields, especially in the synthesis of natural products and new drugs. For example, the D. Burke group used an intermediate building block containing MIDA boronic ester to achieve the first stereo-controlled total synthesis of the natural product (-)-peridinin through only iterative Suzuki-Miyaura cross-coupling reactions. However, reports on α-BMIDA esters are relatively few. For instance, the Yudin group reported the conversion of α-BMIDA aldehydes to α-BMIDA esters via Pinnick oxidation and methyl esterification. Subsequently, they studied the introduction of a boron group into the α-position of acetoacetate esters under Lewis acid conditions through the reaction of acyl-BMIDA boronic esters with diazonium acetate, thus providing a new route for the synthesis of α-BMIDA esters.

[0005]

[0006]

[0007] Currently, the large-scale industrial production of α-BMIDA ester compounds generally faces severe challenges such as harsh reaction conditions and limited substrate applicability. Existing synthetic methods require oxidation processes, which may lead to poor compatibility with substrates with unstable functional groups, and require two-step reactions to prepare the target product, resulting in relatively low efficiency. In addition, although some research methods have achieved one-step synthesis of α-BMIDA esters, the diazo compounds used in these methods pose significant safety hazards in large-scale production due to their inherent instability and explosiveness, making them unsuitable for industrial application. Therefore, existing synthetic strategies often have significant limitations, restricting their widespread application in related fields. Summary of the Invention

[0008] Technical Problem to be Solved: To address the aforementioned technical problems, the present invention aims to provide a method for preparing α-BMIDA ester compounds. This method uses α-BMIDA propylene ester and potassium alkyl trifluoroborate as substrates, and generates α-BMIDA esters through intermolecular free radical addition-protonation reaction under photocatalytic conditions. This achieves the goal of efficient and universal synthesis of α-BMIDA esters with different functional groups. The present invention provides a simple, mild, high-yield, and low-cost method for synthesizing α-BMIDA esters, offering an economical and convenient solution and technical support for the large-scale preparation of α-BMIDA ester compounds.

[0009] Technical solution: A method for preparing an α-BMIDA ester compound, comprising the following steps: Step 1. Using α-BMIDA propylene ester and potassium alkyl trifluoroborate as substrates, Ir[dF(CF3)ppy]2(dtbbpy)PF6 is added to obtain a pre-reaction system; the molecular formula of the potassium alkyl trifluoroborate is selected from one of the following chemical molecular structures: ; Step 2. The pre-reaction system was reacted at room temperature, and then separated, purified, eluted, and dried to obtain the α-BMIDA ester compound; the reaction formula for its synthesis is as follows:

[0010] In step 2, the α-BMIDA ester compound has one of the following chemical molecular structures:

[0011] The principle of this reaction is as follows: potassium trifluoroborate (substrate S) undergoes single-electron oxidation with an excited-state photocatalyst to generate alkyl radical I-1, which then undergoes radical addition with α-BMIDA propylene ester (substrate S-2) to generate free intermediate I-2. Free radical intermediate I-2 is reduced to a carbanion by the photocatalyst and protonated to obtain α-BMIDA ester; its reaction mechanism diagram is shown below.

[0012]

[0013] Preferably, in step 1, the molar ratio of α-BMIDA propylene ester, alkyl trifluoroborate potassium salt, and Ir[dF(CF3)ppy]2(dtbbpy)PF6 is (0.3-0.4):0.2:(0.002-0.004); more preferably, the molar ratio of α-BMIDA propylene ester, alkyl trifluoroborate potassium salt, and Ir[dF(CF3)ppy]2(dtbbpy)PF6 is 0.3:0.2:0.002.

[0014] Preferably, the reaction conditions in step 2 are nitrogen gas, blue light with a wavelength of 455-465 nm, and a reaction time of 60-72 h. Beneficial effects

[0015] This invention utilizes a photocatalytic intermolecular radical addition-protonation reaction method using α-BMIDA propylene ester and potassium alkyl trifluoroborate as substrates. The potassium alkyl trifluoroborate undergoes single-electron oxidation to generate alkyl radicals. These alkyl radicals then react with α-BMIDA propylene ester through radical addition and protonation, effectively allowing for the efficient synthesis of α-BMIDA esters containing different functional groups.

[0016] The method described in this invention does not require the use of an oxidant, employs a photocatalytic method, and the product is compatible with various functional groups such as amino, alkoxy, and ester groups. It avoids the use of diazo compounds, simplifies the operation process to the greatest extent, and significantly improves the safety and environmental friendliness of the industrial production of α-BMIDA esters. The method described in this invention has the characteristics of simple process, mild conditions, high yield, and low cost. It can provide a new idea for the synthesis of polysubstituted alkyl MIDA borate esters and will lay a solid foundation for the widespread application of α-BMIDA compounds. Attached Figure Description

[0017] Figure 1 This is the proton spectrum of the target product P1 in Example 1; Figure 2 This is the carbon spectrum of the target product P1 in Example 1; Figure 3 This is the boron spectrum of the target product P1 in Example 1; Figure 4 This is the proton spectrum of the target product P2 in Example 2; Figure 5 This is the carbon spectrum of the target product P2 in Example 2; Figure 6 This is the boron spectrum of the target product P2 in Example 2; Figure 7 This is the proton spectrum of the target product P3 in Example 3; Figure 8 This is the carbon spectrum of the target product P3 in Example 3; Figure 9 This is the boron spectrum of the target product P3 in Example 3; Figure 10 This is the proton spectrum of the target product P4 in Example 4; Figure 11 This is the carbon spectrum of the target product P4 in Example 4; Figure 12 This is the boron spectrum of the target product P4 in Example 4; Figure 13 This is the proton spectrum of the target product P5 in Example 5; Figure 14 This is the carbon spectrum of the target product P5 in Example 5; Figure 15 This is the boron spectrum of the target product P5 in Example 5; Figure 16 This is the proton spectrum of the target product P6 in Example 6; Figure 17 This is the carbon spectrum of the target product P6 in Example 6; Figure 18 This is the boron spectrum of the target product P6 in Example 6; Figure 19 This is the proton spectrum of the target product P7 in Example 7; Figure 20 This is the carbon spectrum of the target product P7 in Example 7; Figure 21 This is the boron spectrum of the target product P7 in Example 7. Detailed Implementation

[0018] The present invention will be further described below with reference to embodiments. These embodiments are illustrative of the present invention, but the present invention is not limited to these embodiments: Example 1

[0019] A method for preparing an α-BMIDA ester compound includes the following steps: Step 1. Add 2.24 mg Ir[dF(CF3)ppy]2(dtbbpy)PF6 (0.002 mmol), 45.0 mg S1 (0.3 mmol), and 60.6 mg S-2 (0.2 mmol) to a 10 mL Schlenk tube; Step 2. Add 2 mL of CH3CN to a 10 mL Schlenk tube and degas. Irradiate the tube with a 3W blue LED lamp at room temperature and N2 for 60 h. After the reaction, separate and purify the product by chromatography column using a gradient elution with a mixed solvent of petroleum ether and acetone at volume ratios of 50:1, 40:1, 30:1, 20:1, and 10:1. Collect the fraction containing the target product P1, combine the fractions, and remove the solvent under vacuum to obtain the target product P1 (yield 82%). The molecular structure and chemical reaction formula of P1 are as follows.

[0020]

[0021]

[0022] Depend on Figure 1 , Figure 2 and Figure 3 The proton NMR spectrum of the target product P1 is as follows: 1 H NMR (400 MHz, CDCl3) δ = 7.39(t, J = 7.9 Hz, 2H), 7.24 (t, J = 7.4 Hz, 1H), 7.03 (d, J = 7.7 Hz, 2H), 3.94(dd, J = 16.7, 2.5 Hz, 2H), 3.76 (dd, J = 16.7, 11.4 Hz, 2H), 3.10 (s, 3H), 2.48 (dd, J = 11.5, 2.3 Hz, 1H), 2.10-1.95 (m, 1H), 1.83-1.71 (m, 1H), 1.49(ddd, J = 13.6, 9.1, 2.5 Hz, 1H), 0.99 (dd, J = 6.5, 3.8 Hz, 6H); Carbon spectrum of target product P1: 13C NMR (100 MHz, CDCl3) δ = 176.2, 167.3, 167.2, 150.6, 129.6, 126.0, 121.6, 62.9, 62.5, 46.0, 36.4, 28.3, 23.3, 21.4; Boron spectrum of target product P1: 11 B NMR (128MHz, CDCl3) δ = 12.7. Example 2

[0023] A method for preparing an α-BMIDA ester compound includes the following steps: Step 1. Add 2.24 mg Ir[dF(CF3)ppy]2(dtbbpy)PF6 (0.002 mmol), 52.8 mg S2 (0.3 mmol), and 60.6 mg S-2 (0.2 mmol) to a 10 mL Schlenk tube; Step 2. Add 2 mL of CH3CN to a 10 mL Schlenk tube and degas. Irradiate the tube with a 3W blue LED lamp at room temperature and N2 for 60 h. After the reaction, separate and purify the product by chromatography column using a gradient elution with a mixed solvent of petroleum ether and acetone at volume ratios of 50:1, 40:1, 30:1, 20:1, and 10:1. Collect the fraction containing the target product P1, combine the fractions, and remove the solvent under vacuum to obtain the target product P2 (yield 83%). The molecular structure and chemical reaction formula of P2 are as follows.

[0024]

[0025]

[0026] Depend on Figure 4 , Figure 5 and Figure 6 The proton NMR spectrum of the target product P2 is as follows: 1 H NMR (400 MHz, CDCl3) δ = 7.46-7.33 (m, 2H), 7.26-7.18 (m, 1H), 7.07-6.96 (m, 2H), 3.92 (dd, J = 16.7, 2.4Hz, 2H), 3.73 (dd, J = 16.5, 14.9 Hz, 2H), 3.07 (s, 3H), 2.42 (dd, J= 11.5, 2.5 Hz, 1H), 2.17-2.07 (m, 1H), 1.98-1.79 (m, 3H), 1.67-1.49 (m, 5H), 1.20-1.06 (m, 2H); Carbon spectrum of target product P2: 13 C NMR (100 MHz, CDCl3) δ = 176.3, 167.4, 167.2, 150.6, 129.6, 126.0, 121.6, 62.9, 62.5, 46.0, 40.6, 33.7, 33.1, 31.9, 25.2, 25.0; Boron spectrum of target product P2: 11 B NMR (128 MHz, CDCl3) δ = 12.24. Example 3

[0027] A method for preparing an α-BMIDA ester compound includes the following steps: Step 1. Add 2.24 mg Ir[dF(CF3)ppy]2(dtbbpy)PF6 (0.002 mmol), 49.2 mg S3 (0.3 mmol), and 60.6 mg S-2 (0.2 mmol) to a 10 mL Schlenk tube; Step 2. Add 2 mL of CH3CN to a 10 mL Schlenk tube and degas. Irradiate the tube with a 3W blue LED lamp at room temperature and N2 for 60 h. After the reaction, separate and purify the product by chromatographic column separation. Use a mixed solvent of petroleum ether and acetone for gradient elution with elution volume ratios of 50:1, 40:1, 30:1, 20:1, and 10:1. Collect the fraction containing the target product P1, combine the fractions, and remove the solvent under vacuum to obtain the target product P3 (yield 85%). The molecular structure and chemical reaction formula of P3 are as follows.

[0028]

[0029]

[0030] Depend on Figure 7 , Figure 8 and Figure 9 The proton NMR spectrum of the target product P3 is as follows: 1 H NMR (400 MHz, CDCl3) δ = 7.39(t, J = 7.9 Hz, 2H), 7.23 (t, J = 7.4 Hz, 1H), 7.03 (d, J= 7.7 Hz, 2H), 3.94(dd, J = 16.8, 4.1 Hz, 2H), 3.74 (dd, J = 16.7, 4.5 Hz, 2H), 3.11 (s, 3H), 2.52 (d, J = 10.7 Hz, 1H), 2.06 (dd, J = 13.7, 11.1 Hz, 1H), 1.58 (d, J =14.0 Hz, 1H), 0.99 (s, 9H); Carbon spectrum of target product P3: 13 C NMR (100 MHz, CDCl3) δ =177.6, 166.7, 166.33, 150.7, 129.6, 126.0, 121.4, 62.9, 62.8, 46.0, 40.9, 32.0, 29.7, 29.1; Boron spectrum of target product P3: 11 B NMR (128 MHz, CDCl3) δ = 11.6. Example 4

[0031] A method for preparing an α-BMIDA ester compound includes the following steps: Step 1. Add 2.24 mg Ir[dF(CF3)ppy]2(dtbbpy)PF6 (0.002 mmol), 58.2 mg S4 (0.3 mmol), and 60.6 mg S-2 (0.2 mmol) to a 10 mL Schlenk tube; Step 2. Add 2 mL of CH3CN to a 10 mL Schlenk tube and degas. React at room temperature and under N2 conditions with a 3W blue LED lamp for 60 h. After the reaction, separate and purify by chromatographic column separation using a mixed solvent of petroleum ether and acetone for gradient elution at volume ratios of 50:1, 40:1, 30:1, 20:1, and 10:1. Collect the fraction containing the target product P1, combine them, and remove the solvent under vacuum to obtain the target product P4 (yield 86%). The molecular structure and chemical reaction formula of P4 are as follows.

[0032]

[0033]

[0034] Depend on Figure 10 , Figure 11 and Figure 12 The proton NMR spectrum of the target product P4 is as follows: 1H NMR (400 MHz, CDCl3) δ =7.42-7.31 (m, 2H), 7.23-7.17 (m, 1H), 7.03 (dd, J = 8.5, 1.0 Hz, 2H), 3.93(dd, J = 16.8, 3.1 Hz, 2H), 3.76 (d, J = 16.8 Hz, 2H), 3.55-3.40 (m, 2H), 3.08 (s, 3H), 2.54 (dd, J = 10.8, 2.6 Hz, 1H), 2.26–2.14 (m, 1H), 1.95–1.81 (m, 1H), 1.18 (s, 9H); Carbon spectrum of target product P4: 13 C NMR (100 MHz, CDCl3) δ = 175.6, 167.4, 167.3, 150.6, 129.5, 125.9, 121.7, 72.8, 62.9, 62.5, 60.8, 46.2, 28.2, 27.6; Boron spectrum of target product P4: 11 B NMR (128 MHz, CDCl3) δ = 12.3. Example 5

[0035] A method for preparing an α-BMIDA ester compound includes the following steps: Step 1. Add 2.24 mg Ir[dF(CF3)ppy]2(dtbbpy)PF6 (0.002 mmol), 61.8 mg S5 (0.3 mmol), and 60.6 mg S-2 (0.2 mmol) to a 10 mL Schlenk tube; Step 2. Add 2 mL of CH3CN to a 10 mL Schlenk tube and degas. Irradiate the tube with a 3W blue LED lamp at room temperature and N2 for 60 h. After the reaction, separate and purify the product by chromatographic column separation. Use a mixed solvent of petroleum ether and acetone for gradient elution with elution volume ratios of 50:1, 40:1, 30:1, 20:1, and 10:1. Collect the fraction containing the target product P1, combine the fractions, and remove the solvent under vacuum to obtain the target product P5 (yield 80%). The molecular structure and chemical reaction formula of P5 are as follows.

[0036]

[0037]

[0038] Depend on Figure 13 , Figure 14 and Figure 15 The proton NMR spectrum of the target product P5 is as follows: 1 H NMR (400 MHz, CDCl3) δ =7.44-7.34 (m, 2H), 7.23 (t, J = 7.4 Hz, 1H), 7.09-7.02 (m, 2H), 4.04-3.88 (m,3H), 3.78 (d, J = 16.7 Hz, 2H), 3.60-3.47 (m, 2H), 3.09 (s, 3H), 2.52 (dd, J = 10.7, 2.7 Hz, 1H), 2.24 (dtd, J = 16.3, 11.0, 5.6 Hz, 1H), 2.03-1.92 (m, 1H), 1.78-1.58 (m, 6H), 1.57-1.47 (m, 2H); Carbon spectrum of target product P5: 13 C NMR (100 MHz, CDCl3) δ = 175.6, 167.4, 167.3, 150.6, 129.5, 125.9, 121.6, 81.4, 68.0, 63.0, 62.5, 46.2, 32.3, 32.1, 27.7, 23.5, 23.46; Boron spectrum of target product P5: 11 B NMR (128 MHz, CDCl3) δ = 12.5. Example 6

[0039] A method for preparing an α-BMIDA ester compound includes the following steps: Step 1. Add 2.24 mg Ir[dF(CF3)ppy]2(dtbbpy)PF6 (0.002 mmol), 96.4 mg S6 (0.3 mmol), and 60.6 mg S-2 (0.2 mmol) to a 10 mL Schlenk tube; Step 2. Add 2 mL of CH3CN to a 10 mL Schlenk tube and degas. React at room temperature and under N2 conditions with a 3W blue LED lamp for 60 h. After the reaction, separate and purify by chromatographic column separation using a mixed solvent of petroleum ether and acetone for gradient elution at volume ratios of 50:1, 40:1, 30:1, 20:1, and 10:1. Collect the fraction containing the target product P1, combine them, and remove the solvent under vacuum to obtain the target product P6 (yield 70%). The molecular structure and chemical reaction formula of P6 are as follows.

[0040]

[0041]

[0042] Depend on Figure 16 , Figure 17 and Figure 18 The proton NMR spectrum of the target product P6 is as follows: 1 H NMR (400 MHz, CDCl3) δ =7.36 (t, J = 7.9 Hz, 2H), 7.21 (t, J = 7.4 Hz, 1H), 7.00 (d, J = 7.7 Hz, 2H), 3.90 (dd, J = 16.5, 9.3 Hz, 2H), 3.83-3.70 (m, 4H), 3.60 (t, J = 6.1 Hz, 2H),3.50-3.39 (m, 1H), 3.16-2.98 (m, 5H), 2.52 (dd, J = 10.3, 2.5 Hz, 1H), 2.31-2.17 (m, 1H), 2.05-1.97 (m, 1H), 1.85-1.76 (m, 2H), 1.52-1.45 (m, 2H), 1.44 (s, 9H); Carbon spectrum of target product P6: 13 C NMR (100 MHz, CDCl3) δ = 175.5, 167.1, 166.9, 154.8, 150.6, 129.6, 126.0, 121.5, 79.4, 74.8, 67.2, 63.1, 62.5, 46.2, 41.3, 31.2, 31.0, 28.4, 27.8; Boron spectrum of target product P6: 11 B NMR (128 MHz, CDCl3) δ = 10.7. Example 7

[0043] A method for preparing an α-BMIDA ester compound includes the following steps: Step 1. Add 2.24 mg Ir[dF(CF3)ppy]2(dtbbpy)PF6 (0.002 mmol), 70.8 mg S7 (0.3 mmol), and 60.6 mg S-2 (0.2 mmol) to a 10 mL Schlenk tube; Step 2. Add 2 mL of CH3CN to a 10 mL Schlenk tube and degas. React at room temperature and under N2 conditions with a 3W blue LED lamp for 60 h. After the reaction, separate and purify by chromatographic column separation using a mixed solvent of petroleum ether and acetone for gradient elution at volume ratios of 50:1, 40:1, 30:1, 20:1, and 10:1. Collect the fraction containing the target product P1, combine them, and remove the solvent under vacuum to obtain the target product P7 (yield 80%). The molecular structure and chemical reaction formula of P7 are as follows.

[0044]

[0045]

[0046] Depend on Figure 19 , Figure 20 and Figure 21 The proton NMR spectrum of the target product P7 is as follows: 1 H NMR (400 MHz, CDCl3) δ =7.36 (t, J = 7.9 Hz, 2H), 7.21 (t, J = 7.4 Hz, 1H), 7.01 (d, J = 7.6 Hz, 2H), 3.90 (d, J = 16.4 Hz, 2H), 3.73 (dd, J = 16.6, 6.3 Hz, 2H), 3.64 (s, 3H), 3.14 (s, 3H), 2.51 (d, J = 10.4 Hz, 1H), 2.38-2.25 (m, 2H), 2.12-2.01 (m, 1H), 1.70-1.56 (m, 3H), 0.94 (s, 3H), 0.93 (s, 3H); Carbon spectrum of target product P7: 13 C NMR (100 MHz, CDCl3) δ = 177.0, 174.7, 167.1, 166.8, 150.7, 129.6, 126.0, 121.5, 62.9, 62.7, 51.6, 46.1, 38.6, 36.1, 34.1, 29.2, 26.3, 26.2; Boron spectrum of target product P7: 11 B NMR (128 MHz, CDCl3) δ = 11.71. Comparative Example 1

[0047] The difference between this comparative example and Example 1 is that blue light treatment is not used.

[0048] A method for preparing an α-BMIDA ester compound includes the following steps: Step 1. Add 2.24 mg Ir[dF(CF3)ppy]2(dtbbpy)PF6 (0.002 mmol), 45.0 mg S1 (0.3 mmol), and 60.6 mg S-2 (0.2 mmol) to a 10 mL Schlenk tube; Step 2. Add 2 mL of CH3CN to a 10 mL Schlenk tube and degas. React at room temperature and under N2 conditions for 60 h. After the reaction, separate and purify by chromatographic column separation. Use a mixed solvent of petroleum ether and acetone for gradient elution with elution volume ratios of 50:1, 40:1, 30:1, 20:1, and 10:1 respectively. Collect the fraction containing the target product P1, combine them, and remove the solvent under vacuum to obtain the target product P1 (yield 0%). Comparative Example 2

[0049] The difference between this comparative example and Example 1 is that Ir[dF(CF3)ppy]2(dtbbpy)PF6 is replaced with 4-CzIPN.

[0050] A method for preparing an α-BMIDA ester compound includes the following steps: Step 1. Take 0.58mg of 4-CzIPN 0.002 mmol, 45.0 mg S1 (0.3 mmol), and 60.6 mg S-2 (0.2 mmol) were added to a 10 mL Schlenk tube; Step 2. Add 2 mL of CH3CN to a 10 mL Schlenk tube and degas. Incubate at room temperature and under N2 conditions with a 3W blue LED lamp for 60 h. After the reaction, separate and purify by chromatographic column separation using a mixed solvent of petroleum ether and acetone for gradient elution at volume ratios of 50:1, 40:1, 30:1, 20:1, and 10:1. Collect the fraction containing the target product P1, combine them, and remove the solvent under vacuum to obtain the target product P1 (yield 50%). Comparative Example 3

[0051] The difference between this comparative example and Example 1 is that nitrogen is replaced with air.

[0052] A method for preparing an α-BMIDA ester compound includes the following steps: Step 1. Add 2.24 mg Ir[dF(CF3)ppy]2(dtbbpy)PF6 (0.002 mmol), 45.0 mg S1 (0.3 mmol), and 60.6 mg S-2 (0.2 mmol) to a 10 mL Schlenk tube; Step 2. Add 2 mL of CH3CN to a 10 mL Schlenk tube and degas. Irradiate the tube with a 3W blue LED lamp at room temperature for 60 h. After the reaction, separate and purify the product by chromatography column using a gradient elution with a mixed solvent of petroleum ether and acetone at volume ratios of 50:1, 40:1, 30:1, 20:1, and 10:1. Collect the fraction containing the target product P1, combine the fractions, and remove the solvent under vacuum to obtain the target product P1 (yield 4%).

[0053] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention, or modify them into equivalent embodiments, without departing from the spirit and technical essence of the present invention. Therefore, any simple modifications, equivalent substitutions, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the content of the technical solutions of the present invention, shall still fall within the scope of protection of the present invention.

Claims

1. A method for preparing an α-BMIDA ester compound, characterized in that, Includes the following steps: Step 1. Using α-BMIDA propylene ester and alkyl trifluoroborate potassium salt as substrates, Ir[dF(CF3)ppy]2(dtbbpy)PF6 was added to obtain a pre-reaction system; Step 2. The pre-reaction system was reacted at room temperature, and then separated, purified, eluted and dried to obtain the α-BMIDA ester compound.

2. The method for preparing an α-BMIDA ester compound according to claim 1, characterized in that: In step 1, the molecular formula of the potassium alkyl trifluoroborate salt is selected from one of the following chemical molecular structures: 。 3. The method for preparing an α-BMIDA ester compound according to claim 1, characterized in that: In step 1, the molar ratio of α-BMIDA propylene ester, potassium alkyl trifluoroborate, and Ir[dF(CF3)ppy]2(dtbbpy)PF6 is (0.3-0.4):0.2:(0.002-0.004).

4. The method for preparing an α-BMIDA ester compound according to claim 1, characterized in that: The reaction conditions in step 2 are nitrogen gas, blue light with a wavelength of 455-465 nm, and a reaction time of 60-72 h.

5. The method for preparing an α-BMIDA ester compound according to claim 1, characterized in that: The α-BMIDA ester compound in step 2 has one of the following chemical molecular structures: 。 6. An α-BMIDA ester compound prepared by the method according to any one of claims 1-5.

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