Tetra-coordinated boron-oxygen heterocyclic compound and preparation method thereof

Abstract

The invention discloses a tetra-coordinated boron-oxygen heterocyclic compound and a preparation method thereof, and belongs to the technical field of pharmaceutical and chemical intermediates and related chemistry. The method comprises the following steps: by taking a bis (pentafluorophenyl) borane dimethyl sulfide complex [(C6F5) 2BHSMe2] as a boron source, firstly carrying out hydroboronation reaction on the bis (pentafluorophenyl) borane dimethyl sulfide complex [(C6F5) 2BHSMe2] and an eneyne compound to generate a three-coordination alkenyl boron dienophile intermediate in situ, and then carrying out reverse electron demand Diels-Alder reaction on the three-coordination alkenyl boron dienophile intermediate and an acetylenic ketone compound to synthesize a series of tetra-coordination boron-oxygen heterocyclic compounds. The method has the advantages of mild reaction conditions, good selectivity, high yield, wide substrate application range, environmental friendliness, simplicity and convenience in operation and the like, opens up a new way for synthesis of the tetra-coordinated organoboron compound, and has higher application value and social and economic benefits.

Description

Technical Field

[0001] This invention relates to a novel method for preparing a four-coordinate boron-oxygen heterocyclic compound, belonging to the fields of pharmaceutical and chemical intermediates and related chemical technologies; specifically, it relates to a method for preparing a four-coordinate boron-oxygen heterocyclic compound based on the reverse electron-demanding Diels-Alder reaction of bis(pentafluorophenyl)enylboron and acetylene ketones, using bis(pentafluorophenyl)enylboron intermediates and acetylene ketone compounds as raw materials. Background Technology

[0002] Tetracoordinate organoboron compounds, due to their unique electronic structure and reactivity, show broad application prospects in organic synthesis, materials science, and medicinal chemistry. Compared with common tricoordinate boron esters, tetracoordinate boron compounds exhibit higher stability and unique reaction modes. The negative charge on their boron atoms can be delocalized through a conjugated system to form "boron-centered anion" species with specific reactivity. Among them, bis(pentafluorophenyl)borane derivatives possess unique electronic properties due to their strongly electron-withdrawing pentafluorophenyl groups, providing possibilities for regulating reactivity. The reverse electron-demand Diels-Alder reaction, as an important method for efficiently constructing six-membered cyclic skeletons, demonstrates unique application value in organic synthesis. Unlike the normal electron-demand Diels-Alder reaction, the IEDDA reaction involves a [4+2] cycloaddition between an electron-deficient diene and an electron-rich dienophile. This reversal of electron demand makes it complementary to classical reactions in terms of reaction mode and product structure, providing a unique synthetic strategy for constructing complex polycyclic skeletons. However, no studies have been reported to date on the IEDDA reaction of bis(pentafluorophenyl)enylboron as a dienophile with acetylacetonates, and its reactivity, regioselectivity, and stereoselectivity remain unclear. Therefore, developing an efficient, mild, and selective method for preparing tetracoordinated boron-oxygen heterocyclic compounds is of great significance. Summary of the Invention

[0003] To address the problems existing in the prior art, this invention provides a four-coordinate boron-oxygen heterocyclic compound and its preparation method. This method uses a bis(pentafluorophenyl)borane dimethyl sulfide complex as the boron source, first reacting it with an enyne to generate a three-coordinate alkenylboron intermediate, and then reacting it with an alkynone via a reverse electron-demanding Diels-Alder reaction to synthesize the four-coordinate boron-oxygen heterocyclic compound. This method has advantages such as mild reaction conditions, good selectivity, high yield, wide substrate applicability, and environmental friendliness. This invention has significant application value and socio-economic benefits.

[0004] The technical solution adopted in this invention is: a four-coordinated boron-oxygen heterocyclic compound, the general structural formula of which is:

[0005]

[0006] Among them, R 1 Selected from phenyl, substituted phenyl, or cycloalkyl; R 2 Selected from C1-C6 alkyl, phenyl, substituted phenyl, cycloalkyl, aryl, heteroaryl, -NR 3 R 4 Among them, R 3 R 4 Each is independently selected from hydrogen and C1-C6 alkyl groups.

[0007] Furthermore, the substituted phenyl group is a C1-C6 alkyl group, a halogen, or a C1-C6 alkoxy-substituted phenyl group; the cycloalkyl group is a 3-8 member cycloalkyl group; the aryl group is naphthyl, anthraceneyl, or phenanthryl; and the heteroaryl group is pyridyl, pyrroleyl, furanyl, thiopheneyl, imidazolyl, pyrazolyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, or benzothiopheneyl.

[0008] Furthermore, R 1 It is selected from one of phenyl, bromophenyl, chlorophenyl, p-methylphenyl, p-propylphenyl, p-methoxyphenyl, o-methoxyphenyl, bonded methoxyphenyl, cyclopropyl, cyclobutyl, and cyclohexyl;

[0009] R 2 Selected from methyl, ethyl, tert-butyl, phenyl, bromophenyl, chlorophenyl, p-methylphenyl, p-propylphenyl, p-methoxyphenyl, o-methoxyphenyl, bonded methoxyphenyl, cyclopropyl, cyclobutyl, cyclohexyl, naphthyl, furanyl, thiophene, and dimethylamino.

[0010] A method for preparing four-coordinate boron-oxygen heterocyclic compounds involves using bis(pentafluorophenyl)enylboron intermediates and acetylacetonates as raw materials to synthesize a series of four-coordinate boron-oxygen heterocyclic compounds:

[0011] The synthesis route is as follows:

[0012] ; In compound 1, R 1 and R 2 Definition and R in compound 2 1 and R 2 The definitions are the same.

[0013] Furthermore, the preparation method is as follows: bis(pentafluorophenyl)borane dimethyl sulfide complex [(C6F5)2BH·SMe2] is dissolved in an organic solvent, 2-methyl-1-buten-3-yne is added, and the reaction is stirred at room temperature to generate a tricoordinated alkenylboron intermediate. Then, compound 1 of the acetylacetonate class is added, and the reaction is carried out at 20℃-100℃ for 8-20 hours. After the reaction is completed, the target product is obtained by post-treatment.

[0014] Furthermore, the molar ratio of the bis(pentafluorophenyl)borane dimethyl sulfide complex, 2-methyl-1-buten-3-yne to compound 1 is 1:(1-1.2):(1-1.2).

[0015] Furthermore, the organic solvent is selected from one or more of dichloromethane, trichloromethane, 1,2-dichloroethane, toluene, and tetrahydrofuran.

[0016] Furthermore, the post-processing steps are as follows: after the reaction is completed, the solvent is removed under vacuum, a mixed solvent of ethanol and n-hexane is added to the system under inert gas protection, the solid is stirred to precipitate, filtered, washed with n-hexane, and dried to obtain the pure target product.

[0017] Specifically, a novel method for preparing four-coordinate boron-oxygen heterocyclic compounds is described, using bis(pentafluorophenyl)enylboron intermediates and acetylacetonates as raw materials, to synthesize a series of four-coordinate boron-oxygen heterocyclic compounds via a Diels-Alder reaction with reverse electron demand. The synthetic route is as follows:

[0018]

[0019] The specific steps include: dissolving the bis(pentafluorophenyl)borane dimethyl sulfide complex [(C6F5)2BH·SMe2] in an organic solvent, adding an alkenyne compound, stirring at room temperature to generate a tricoordinated alkenylboron intermediate, then adding an alkenylone compound, reacting at 25-100℃ for 8-20 hours, and finally obtaining the target product after post-treatment.

[0020] The molar ratio of the bis(pentafluorophenyl)borane dimethyl sulfide complex to the enyne compound is 1:1 to 1:1.2, and the molar ratio to the acetylenoid compound is 1:1 to 1:1.2.

[0021] The enyne compound is 2-methyl-1-buten-3-yne.

[0022] The organic solvent is selected from one or more of dichloromethane, trichloromethane, 1,2-dichloroethane, toluene, and tetrahydrofuran.

[0023] The preferred reaction temperature is 45℃, and the preferred reaction time is 12 hours.

[0024] The post-processing steps include: removing the solvent under vacuum after the reaction is complete, adding a mixed solvent of ethanol and n-hexane to the system under inert gas protection, stirring to precipitate the solid, filtering, washing with n-hexane, and drying to obtain the pure target product.

[0025] R in acetylene compounds 1 Selected from one or more of phenyl, 4-methoxyphenyl, 4-methylphenyl, 4-propylphenyl, 4-chlorophenyl, 4-bromophenyl, and cyclopropyl; R2 It is selected from one or more of phenyl, cyclopropyl, 2-naphthyl, 2-furanyl, 2-thienyl, 4-methoxyphenyl, tert-butyl, and N,N-dimethyl.

[0026] The reaction list is as follows:

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033] Beneficial effects: The method for synthesizing tetracoordinate boron-oxygen heterocyclic compounds of the present invention has the advantages of mild reaction conditions, good selectivity, high yield, wide substrate applicability, and environmental friendliness, specifically:

[0034] (1) This method uses bis(pentafluorophenyl)borane dimethyl sulfide complex as boron source, the raw materials are inexpensive and readily available, and the post-reaction processing is simple; it avoids the problems of high cost and environmental pollution caused by using precious metal catalysts.

[0035] (2) This method is the first to apply bis(pentafluorophenyl)enylboron as a dienophile to the inverse electron demand Diels-Alder reaction, which expands the types of dienophiles for the IEDDA reaction and opens up a new route for the synthesis of tetracoordinate organoboron compounds.

[0036] (3) The reaction conditions of this method are mild, and the reaction can be carried out smoothly at 45℃. The product can be obtained as an analytical grade product through simple precipitation purification. The operation is simple and easy to industrialize.

[0037] (4) This method has a wide range of substrates and good tolerance to various substituents. It can synthesize more than 20 novel tetracoordinate boron-oxygen heterocyclic compounds that have not been reported in the literature, with a yield of 44-66%.

[0038] In summary, this invention provides a novel method for preparing four-coordinate boron-oxygen heterocyclic compounds. This method uses a bis(pentafluorophenyl)borane dimethyl sulfide complex as the boron source, which undergoes a hydroboration reaction with an alkenyne to generate a three-coordinate alkenylboron dienophile intermediate in situ. This intermediate then undergoes a reverse electron-demanding Diels-Alder reaction with an alkyne ketone, successfully constructing a novel four-coordinate boron-oxygen heterocyclic framework. This method features mild reaction conditions (45°C), simple operation, good selectivity, and a wide range of substrate compatibility (compatible with various R...). 1 / R 2 This invention offers significant advantages, including the use of substituents and good yields (44-66%). The product can be purified to analytical grade through simple precipitation. This invention not only opens up new pathways for the synthesis of tetracoordinate organoboron compounds and enriches the types of dienophiles in the IEDDA reaction, but also lays a solid foundation for the further application of these compounds in organic synthesis, medicinal chemistry, and materials science. It possesses significant academic value and potential industrial application potential. Attached Figure Description

[0039] Figure 1 For compound 2-2 1 H-NMR.

[0040] Figure 2 For compound 2-2 13 C-NMR.

[0041] Figure 3 For compound 2-2 11 B-NMR.

[0042] Figure 4 For compound 2-2 19 F-NMR.

[0043] Figure 5 For compound 2-1 1 H-NMR.

[0044] Figure 6 For compound 2-1 13 C-NMR.

[0045] Figure 7 For compounds 2-5 1 H-NMR.

[0046] Figure 8 For compounds 2-5 13 C-NMR.

[0047] Figure 9 For compound 2-10 1 H-NMR.

[0048] Figure 10 For compound 2-1013 C-NMR.

[0049] Figure 11 For compound 2-19 1 H-NMR.

[0050] Figure 12 For compound 2-19 13 C-NMR.

[0051] Figure 13 For compound 2-20 1 H-NMR.

[0052] Figure 14 For compound 2-20 13 C-NMR.

[0053] Figure 15 For compound 2-21 1 H-NMR.

[0054] Figure 16 For compound 2-21 13 C-NMR. Detailed Implementation

[0055] The present invention will be further illustrated below with reference to specific embodiments. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Simple substitutions or modifications made to the present invention by those skilled in the art are all within the scope of the technical solutions protected by the present invention.

[0056] Example 1: Synthesis of Compound 2-2:

[0057]

[0058] Accurately weigh 0.5 mmol of bis(pentafluorophenyl)borane dimethyl sulfide complex [(C6F5)2BH·SMe2] into a side-mounted flask containing a magnetic flask. Dissolve the mixture in 5 mL of DCM, then add a DCM solution of 0.5 mmol of 2-methyl-1-buten-3-yne. Stir the mixture at room temperature for 2 hours, then add the acetylacetone substrate 1-2 (R 1 = Ph, R 2 A DCM solution (pH 0.5 mmol) was prepared and reacted at 45 °C for 12 hours. After the reaction was complete, the solvent was removed under vacuum, and approximately 0.5 mL of ethanol and 1.5 mL of n-hexane were slowly added to the system under N2 protection. With stirring, a large amount of solid gradually precipitated as n-hexane was added. Stirring continued until no more solid precipitated in the system. The solid was settled, and the supernatant was filtered off. The lower solid was washed three times with n-hexane, and the residual solvent was removed under reduced pressure to obtain the pure target product 2-2, with a yield of 47%. 1H NMR (500 MHz, CDCl3) δ 7.66 (d, J = 7.7 Hz, 2H), 7.43 (t, J = 7.5 Hz, 1H), 7.12 (dt, J = 29.9, 7.3 Hz, 6H), 5.98 (s, 1H), 3.86 - 3.60 (m, 2H), 2.90 (dd, J = 21.8, 5.6 Hz, 1H), 1.71 (s, 3H); 13 C NMR(126 MHz, CDCl3) δ 207.55, 157.79, 149.35, 147.78, 147.31, 145.92, 139.30,138.25, 137.73, 136.27, 136.17, 136.05, 132.22, 130.77, 129.34, 128.41,128.39, 128.23, 121.77, 77.23, 45.38, 40.31, 31.62, 22.68, 22.55, 14.13; 11 BNMR (160 MHz, CDCl3) δ 7.51; 19 F NMR (471 MHz, CDCl3) δ -133.65 (dd, J = 24.2,9.1 Hz), -135.20 (dd, J = 24.7, 8.9 Hz), -157.67 (t, J = 20.1 Hz), -158.02(t, J = 20.4 Hz), -163.76 (ddd, J = 23.7, 19.4, 8.8 Hz), -164.26 (td, J =22.9, 9.4 Hz).

[0059] Example 2 Synthesis of compound 2-1:

[0060]

[0061] Following the method of Example 1, the acetylene substrate was replaced with 1-1 (R 1 = Ph, R 2 = Cyclopropyl), to obtain the target product 2-1, with a yield of 52%. 1H NMR (500 MHz, CDCl3) δ 7.60 - 7.06 (m, 6H), 5.82 (s, 1H), 3.57 - 3.29 (m, 2H), 2.83 (dd, J = 21.5, 5.3 Hz, 1H), 1.87 (dp, J = 8.6, 4.1Hz, 1H), 1.61 (t, J = 8.5 Hz, 2H), 1.32 (tq, J = 9.2, 5.3 Hz, 1H), 1.19 (qd,J = 8.2, 3.4 Hz, 1H); 13 C NMR (126 MHz, CDCl3) δ 218.16, 157.00, 149.09,147.78, 147.19, 145.90, 139.85, 139.66, 138.17, 138.04, 137.89, 136.18,136.04, 135.92, 129.51, 129.03, 128.81, 121.94, 77.21, 41.89, 40.91, 22.44,20.39, 20.35, 20.29; 11 B NMR (160 MHz, CDCl3) δ 7.11; 19 F NMR (471 MHz, CDCl3) δ-133.79 (dd, J = 24.2, 9.1 Hz), -135.20 (dd, J = 24.6, 8.9 Hz), -158.12 (dt,J = 101.8, 20.3 Hz), -163.87 (td, J = 23.0, 8.8 Hz), -164.42 (td, J = 22.7,9.5 Hz).

[0062] Example 3 Synthesis of compounds 2-5:

[0063]

[0064] Following the method of Example 1, the acetylene substrate was replaced with 1-5 (R 1 = Ph, R 2 = 4-methoxyphenyl), to obtain target products 2-5, with a yield of 64%. 1H NMR (500 MHz, CDCl3) δ 7.69 (d, J = 8.5 Hz, 1H), 7.25 (s, 0H), 7.12 (d, J = 6.7 Hz, 1H), 6.61 (d, J = 8.6 Hz, 1H), 5.98 (s, 0H), 3.80 (s, 1H), 3.74 - 3.58 (m, 1H); 13 C NMR (126 MHz, CDCl3) δ 204.06, 166.53,154.35, 139.75, 137.06, 135.62, 128.89, 128.34, 128.00, 122.97, 121.84,121.80, 114.03, 55.79, 40.11, 22.53; 11 B NMR (160 MHz, CDCl3) δ 6.57; 19 F NMR(471 MHz, CDCl3) δ -133.67 (dd, J = 24.2, 9.3 Hz), -135.13 (dd, J = 25.0, 9.0Hz), -158.03 (t, J = 20.2 Hz), -158.41 (t, J = 20.4 Hz), -164.06 (ddd, J =24.1, 19.8, 9.1 Hz), -164.19 - -164.51 (m).

[0065] Example 4 Synthesis of compounds 2-10:

[0066]

[0067] Following the method of Example 1, the acetylene substrate was replaced with 1-10 (R 1 = 4-propylphenyl, R 2 = 4-methoxyphenyl), to obtain the target product 2-10, with a yield of 63%. 1H NMR (500 MHz, CDCl3) δ 7.67 (d, J = 8.5 Hz,2H), 7.15 - 6.55 (m, 6H), 5.98 (s, 1H), 3.78 (s, 3H), 3.74 - 3.56 (m, 2H),2.84 (dd, J = 21.0, 5.1 Hz, 1H), 2.45 (td, J = 7.2, 4.4 Hz, 2H), 1.70 (s,3H), 1.49 (qd, J = 7.2, 4.7 Hz, 2H), 0.81 (t, J = 7.4 Hz, 3H); 13 C NMR (126MHz, CDCl3) δ 204.16, 166.32, 154.92, 143.89, 138.18, 137.17, 136.79, 136.20,135.50, 128.43, 128.15, 123.17, 121.87, 113.94, 113.48, 77.22, 55.67, 45.44,40.05, 37.50, 24.39, 22.57, 14.11, 13.36; 11 B NMR (160 MHz, CDCl3) δ 6.46; 19 FNMR (471 MHz, CDCl3) δ -132.90 (dd, J = 23.8, 8.8 Hz), -133.66 (dd, J = 24.3,9.3 Hz), -135.13 (dd, J = 24.9, 8.9 Hz), -158.11 (t, J = 20.1 Hz), -158.51(t, J = 20.3 Hz), -163.89 (td, J = 22.9, 9.1 Hz), -164.12 (ddd, J = 23.9,19.7, 9.0 Hz), -164.45 (td, J = 22.8, 9.2 Hz).

[0068] Example 5 Synthesis of Compounds 2-19:

[0069]

[0070] Following the method of Example 1, the acetylene substrate was replaced with 1-19 (R 1 = 4-Methoxyphenyl, R 2 = Cyclopropyl), to obtain the target product 2-2s, yield 66%.1 H NMR (500 MHz, CDCl3) δ 7.28 (s, 2H), 6.96 (d,J = 8.1 Hz, 2H), 5.82 (s, 1H), 3.86 (s, 3H), 3.54 - 3.32 (m, 2H), 2.81 (dd, J= 21.0, 5.0 Hz, 1H), 1.88 (dq, J = 7.5, 4.5 Hz, 1H), 1.75 (tt, J = 8.0, 4.4Hz, 1H), 1.61 (tt, J = 6.4, 2.7 Hz, 1H), 1.36 - 1.23 (m, 2H); 13 C NMR (126 MHz, CDCl3) δ 217.71, 160.91, 157.13, 149.09, 147.75, 147.18, 145.85, 139.35,138.09, 137.87, 136.03, 131.85, 129.49, 122.00, 77.23, 55.41, 42.61, 40.87,22.53, 20.22, 20.12, 19.78, 14.13; 11 B NMR (160 MHz, CDCl3) δ 6.98; 19 F NMR (471MHz, CDCl3) δ -133.77 (dd, J = 24.3, 9.3 Hz), -135.28 (dd, J = 24.2, 9.0 Hz), -158.09 (t, J = 20.2 Hz), -158.34 (t, J = 20.4 Hz), -163.87 (ddd, J = 24.2, 20.0, 8.8 Hz), -164.44 (ddd, J = 23.8, 19.7, 9.3 Hz).

[0071] Example 6 Synthesis of Compounds 2-20:

[0072]

[0073] Following the method of Example 1, the acetylene substrate was replaced with 1-20 (R 1 = p-Tolyl, R 2 = phenyl), to obtain the target product 2-20, with a yield of 66%. 1H NMR (500 MHz, CDCl3) δ 7.65 (d, J = 7.7 Hz, 2H), 7.44(t, J = 7.5 Hz, 1H), 7.16 (t, J = 7.7 Hz, 2H), 6.88 (s, 3H), 5.98 (s, 1H),3.83 - 3.59 (m, 2H), 2.88 (dd, J = 21.5, 5.4 Hz, 1H), 2.18 (s, 3H), 1.71 (s,3H); 13 C NMR (126 MHz, CDCl3) δ 207.39, 158.18, 149.20, 147.78, 147.30, 145.87,139.71, 139.10, 138.13, 137.28, 136.46, 136.11, 135.71, 132.17, 130.88,128.80, 128.57, 128.34, 121.79, 77.22, 45.54, 40.27, 22.59, 21.14; 11 B NMR (160MHz, CDCl3) δ 7.22; 19 F NMR (471 MHz, CDCl3) δ -133.64 (dd, J = 24.1, 9.3 Hz), -135.23 (dd, J = 24.5, 9.0 Hz), -157.75 (t, J = 20.3 Hz), -158.10 (t, J =20.4 Hz), -163.81 (ddd, J = 24.5, 20.1, 9.0 Hz), -164.28 (ddd, J = 24.0, 20.0, 9.4 Hz).

[0074] Example 7 Synthesis of Compounds 2-21:

[0075]

[0076] Following the method of Example 1, the acetylene substrate was replaced with 1-21 (R 1 = Cyclopropyl, R 2 = phenyl), to obtain the target product 2-21 in 55% yield. 1H NMR (500 MHz, CDCl3) δ 8.15 (d, J = 7.7 Hz, 2H), 7.77(t, J = 7.5 Hz, 1H), 7.59 (t, J = 7.5 Hz, 2H), 5.87 (s, 1H), 3.64 (t, J = 8.3Hz, 1H), 2.66 (dd, J = 21.9, 11.1 Hz, 1H), 2.28 (dd, J = 21.9, 5.7 Hz, 1H), 1.93 (tt, J = 8.5, 5.0 Hz, 1H), 1.63 (s, 4H), 0.97 (dt, J = 8.0, 4.7 Hz, 1H),0.93 - 0.79 (m, 1H), 0.73 (d, J = 8.6 Hz, 2H); 13 C NMR (126 MHz, CDCl3) δ206.81, 161.89, 147.31, 138.00, 136.76, 136.51, 135.98, 132.62, 132.33,129.17, 126.84, 122.43, 45.60, 32.18, 31.61, 22.59, 18.09, 14.13, 9.27, 9.05; 11 B NMR (160 MHz, CDCl3) δ 6.92; 19 F NMR (471 MHz, CDCl3) δ -133.66 (dd, J =23.7, 9.3 Hz), -135.68 (dd, J = 24.9, 8.9 Hz), -157.96 (t, J = 20.3 Hz), -158.51 (t, J = 20.4 Hz), -164.26 (ddd,J = 24.1, 19.9, 9.1 Hz), -164.41 (td,J = 22.8, 9.4 Hz).

[0077] Example 8: Application of the compound:

[0078] The novel tetracoordinated bis(pentafluorophenyl)boron fused heterocyclic compound provided by this invention has potential applications in multiple fields, as specifically demonstrated below:

[0079] 1. In the field of organic optoelectronic materials: The aromatized products of novel four-coordinate bis(pentafluorophenyl)boron fused heterocyclic compounds possess extended π-conjugated skeletons and strongly electron-withdrawing pentafluorophenyl substituents, exhibiting typical electron donor-acceptor structural characteristics. These compounds exhibit strong fluorescence emission in both solution and solid states, and can be used as emissive layer materials or electron transport materials in organic light-emitting diodes (OLEDs). Similar boron-containing fused ring compounds have been shown in the literature to possess excellent photophysical properties and thermal stability (such as BODIPY fluorescent dyes), and the compounds of this invention are expected to play similar roles in optoelectronic devices.

[0080] 2. Medicinal Chemistry and Synthesis of Bioactive Molecules: Boron-containing compounds play an important role in drug design; for example, marketed drugs such as bortezomib and criborone contain tetracoordinate boron structures. The compounds of this invention can be used to construct diverse biaryl, phenolic, or amine derivatives through subsequent transformations of the CB bond (such as Suzuki-Miyaura coupling, oxidation, reduction, etc.). These structural units are widely found in natural products and drug molecules. Literature indicates that compounds with similar boron heterocyclic structures have shown inhibitory activity against various tumor cells (such as the cytotoxicity of spirocyclic compounds against MHCC-97H, UM-1, and A549 cell lines reported by Sun et al.). The compounds of this invention are structurally similar and hold promise for discovering new lead compounds through further bioactivity screening.

[0081] 3. Lewis acid catalysts: The four-coordinate boron center possesses stable electron-deficient properties, making it suitable as a Lewis acid catalyst for organic conversion reactions, such as carbonyl activation, olefin polymerization, and cycloaddition reactions. Compared to traditional three-coordinate boron catalysts, four-coordinate boron compounds exhibit higher stability and recyclability, demonstrating potential applications in green catalysis.

[0082] 4. Functional material precursors: The compounds of this invention can be further nucleophilically substituted with pentafluorophenyl or functionalized with CB bonds to introduce other functional groups (such as polar groups, chiral groups, polymeric groups, etc.), thereby preparing functional materials with specific properties, such as chiral separation materials, ion exchange membranes, fluorescent probes, etc.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A tetracoordinated boron-oxygen heterocyclic compound, characterized in that: The general structural formula of the compound is: ； Among them, R 1 Selected from phenyl, substituted phenyl, or cycloalkyl; R 2 Selected from C1-C6 alkyl, phenyl, substituted phenyl, cycloalkyl, aryl, heteroaryl, -NR 3 R 4 Among them, R 3 R 4 Each is independently selected from hydrogen and C1-C6 alkyl groups.

2. The tetracoordinated boron-oxygen heterocyclic compound according to claim 1, characterized in that: The substituted phenyl group is a C1-C6 alkyl, halogen, or C1-C6 alkoxy-substituted phenyl group; the cycloalkyl group is a 3-8 member cycloalkyl group; the aryl group is naphthyl, anthracene, or phenanthryl; the heteroaryl group is pyridyl, pyrroleyl, furanyl, thiopheneyl, imidazolyl, pyrazolyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, or benzothiopheneyl.

3. The tetracoordinated boron-oxygen heterocyclic compound according to claim 2, characterized in that: R 1 It is selected from one of phenyl, bromophenyl, chlorophenyl, p-methylphenyl, p-propylphenyl, p-methoxyphenyl, o-methoxyphenyl, bonded methoxyphenyl, cyclopropyl, cyclobutyl, and cyclohexyl; R 2 Selected from methyl, ethyl, tert-butyl, phenyl, bromophenyl, chlorophenyl, p-methylphenyl, p-propylphenyl, p-methoxyphenyl, o-methoxyphenyl, bonded methoxyphenyl, cyclopropyl, cyclobutyl, cyclohexyl, naphthyl, furanyl, thiophene, and dimethylamino.

4. The tetracoordinated boron-oxygen heterocyclic compound according to claim 3, characterized in that: R 1 Selected from phenyl, 4-methoxyphenyl, 4-methylphenyl, 4-propylphenyl, 4-chlorophenyl, 4-bromophenyl, cyclopropyl; R 2 Selected from phenyl, cyclopropyl, 2-naphthyl, 2-furanyl, 2-thienyl, 4-methoxyphenyl, N,N-dimethyl, and tert-butyl.

5. The method for preparing the tetracoordinate boron-oxygen heterocyclic compound according to any one of claims 1-4, characterized in that, A series of four-coordinate boron-oxygen heterocyclic compounds were synthesized using bis(pentafluorophenyl)enylboron intermediates and acetylaceton compounds as starting materials; the synthetic route is as follows: ； In compound 1, R 1 and R 2 Definition and R in compound 2 1 and R 2 The definitions are the same.

6. The method for preparing the four-coordinate boron-oxygen heterocyclic compound according to claim 5, characterized in that, The specific preparation method is as follows: bis(pentafluorophenyl)borane dimethyl sulfide complex [(C6F5)2BH·SMe2] is dissolved in an organic solvent, 2-methyl-1-buten-3-yne is added, and the reaction is stirred at room temperature to generate a tricoordinated alkenylboron intermediate. Then, compound 1 of the acetylacetonate class is added, and the reaction is carried out at 20℃-100℃ for 8-20 hours. After the reaction is completed, the target product is obtained by post-treatment.

7. The method for preparing the four-coordinate boron-oxygen heterocyclic compound according to claim 6, characterized in that, The molar ratio of the bis(pentafluorophenyl)borane dimethyl sulfide complex, 2-methyl-1-buten-3-yne to compound 1 is 1:(1-1.2):(1-1.2).

8. The method for preparing the four-coordinate boron-oxygen heterocyclic compound according to claim 6, characterized in that, The organic solvent is selected from one or more of dichloromethane, trichloromethane, 1,2-dichloroethane, toluene, and tetrahydrofuran.

9. The method for preparing the four-coordinate boron-oxygen heterocyclic compound according to claim 6, characterized in that, The post-processing steps are as follows: after the reaction is completed, the solvent is removed under vacuum, a mixed solvent of ethanol and n-hexane is added to the system under inert gas protection, the solid is stirred to precipitate, filtered, washed with n-hexane, and dried to obtain the pure target product.

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