A preparation method and application of polysubstituted oxazole compounds

Abstract

This patent application discloses a method for preparing a polysubstituted oxazole compound and its application. The method is a polysubstituted oxazole compound obtained by multiple dehydrogenation 1,1-difunctionalization reactions of trivalent metal-catalyzed N-(1-aryl vinyl) amides with various aromatic heterocyclic nucleophiles such as thiophene, indole, and aromatic hydrocarbons. This method has atomic and step economy, and directly uses common and readily available nucleophiles as raw materials. The entire conversion avoids the participation of aryl halides and aryl metal reagents as active sites in the reaction, which meets the development requirements of sustainable chemistry; the substrate for this conversion has a wide range of applications, and the simple and readily available N-(1-aryl vinyl) amide is used as a reaction substrate, while participating in the construction of nitrogen-containing condensed heterocycles as a traceless guiding group; the patent applicant also applies the obtained heterocyclic substrate to the hole transport layer of perovskite solar cells.

Description

Technical Field

[0001] The present patent application relates to the technical field of organic compound synthesis, and more specifically, to a preparation method of a polysubstituted oxazole compound and its application. Background Art

[0002] How to accurately, efficiently and greenly synthesize target structure molecules, and simply build molecular complexity to enrich the molecular library in its application field, has always been a problem that needs to be faced in the field of synthetic chemistry. On this basis, the difunctionalization of olefins has been proven to be a powerful strategy to quickly introduce two different functional groups on the carbon-carbon double bond, thereby simply building molecular complexity. The 2001 Nobel Prize was awarded to K. Barry Sharpless, Ryoji Noyori and William Standish Knowles in recognition of their contributions to the field of chiral catalysis. Among them, the osmium-catalyzed olefin epoxidation and dihydroxylation reactions developed by Sharpless and others can quickly achieve the rapid construction of related biologically active molecules. Inspired by this, the 1,1-difunctionalization and 1,2-difunctionalization reactions of olefins catalyzed by transition metals such as palladium, nickel and copper have made great progress and have been applied to the fields of biomedicine and materials (Org. Biomol. Chem., 2020, 18, 6983–7001).

[0003] In order to achieve the reactivity and site selectivity of olefin difunctionalization, the main strategies adopted by chemists include: 1) using nucleophilic metalation to initiate Wacker-type reactions for 1,2-difunctionalization of olefins. For example, Liu Guosheng's group explored the difunctionalization reactions of olefins including the extremely challenging CF and C-OCF3 bond formation by high-valent metal species (see review: Acc.Chem.Res.2016,49,2413-2423); 2) site-selective CH activation of olefins with the participation of directing groups to achieve 1,2-difunctionalization. In recent years, the Engle group at the Scripps Research Institute has developed a series of olefin 1,2-difunctionalizations, quickly obtained target molecules, and greatly expanded the diversity of potential substrates (see review: Chem.Commun.,2021,57,7610-7624).

[0004] Compared with 1,2-difunctionalization, the development of 1,1-difunctionalization is relatively slow. The reason may be that it is difficult to control the site selectivity of the substrate, so the catalyst usually activates the π bond of the olefin through trans nucleometalation. Therefore, the 1,1-difunctionalization reaction of olefins is very challenging. For example, by using different types of halogenation reagents for oxidative interception of Heck reaction intermediates, Sanford reported adjustable 1,2- and 1,1-arylation of olefins with excellent stereoselectivity (J.Am.Chem.Soc.,2008,130,2150-2151.). Toste achieved the enantioselective 1,1-fluoroarylation of aminoolefins catalyzed by Pd(II) / bisoxazoline (J.Am.Chem.,Soc.2015,137,38,12207–12210). Sigman developed a series of intermolecular olefin 1,1-difunctionalizations with electrophiles and nucleophiles under Pd(0) catalysis (J.Am.Chem.Soc.,2011,133,5784–5787). Recently, Baik and Hong achieved a cationic palladium-catalyzed 1,1-difunctionalization in which two nucleophiles, an electron-rich aromatic and an internal hydroxyl, were realized from N-quinoline amides, providing synthetically valuable and challenging oxygenated quaternary carbon centers (J.Am.Chem.Soc.,2019,141,10048–10059).

[0005] There are even fewer reports on the more challenging 1,1-difunctionalization of olefins based on multiple dehydrogenation strategies.

[0006] Patent application content

[0007] In order to overcome at least one of the problems existing in the above-mentioned prior art, the present patent application provides a method for preparing a polysubstituted oxazole compound: with the assistance of an easily available and traceless weakly coordinating directing group, 1,1-dehydrogenation difunctionalization of olefins is achieved under trivalent metal catalysis, and a variety of electron-rich aromatic rings are directly used as coupling reagents to construct a polycyclic aromatic heterocyclic molecular skeleton.

[0008] Another purpose of this patent application is to provide the application of the above-mentioned multi-substituted oxazole compounds. This patent application simply synthesizes a material molecule based on a diphenylamine synthetic building block through the dehydrogenation 1,1-difunctionalization strategy of olefins. According to the frontier orbital distribution diagram obtained by DFT calculation, it is found that its energy level matches the perovskite solar hole transport material. After UV absorption, fluorescence emission, cyclic voltammetry scanning and other performance characterizations, it is further verified that the material molecule meets the requirements of the hole transport layer of the perovskite solar cell.

[0009] In order to solve the above technical problems, the technical solution adopted by this patent application is:

[0010] A method for preparing a polysubstituted oxazole compound: in an inert solvent and under the action of a trivalent metal catalyst, an N-(1-aryl vinyl)amide compound (Formula II) is reacted with an aromatic heterocyclic compound (Formula III) to obtain a polysubstituted oxazole compound (Formula I). ​​The reaction equation is as follows:

[0011]

[0012] Wherein Ar is an o-, m- or p-substituted benzene ring or condensed ring compound; R is a saturated alkane; and Het is a thiophene compound, a polysubstituted indole compound, an electron-rich condensed ring aromatic compound and a benzene ring compound.

[0013] Preferably, the inert solvent is any one or more of toluene, tetrahydrofuran, 1,4-dioxane, ethylene glycol dimethyl ether, N,N'-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, acetonitrile, 1,2-dichloroethane, ethanol, and water.

[0014] Preferably, the trivalent metal catalyst is any one of pentamethylcyclopentadienylrhodium chloride dimer and pentamethylcyclopentadienyliridium chloride dimer, or a combination thereof.

[0015] Preferably, the halide ion extractor is any one of silver hexafluoroantimonate and silver bistrifluoromethanesulfonyl imide or a combination thereof.

[0016] Preferably, the oxidant is any one or more of silver acetate, silver carbonate, silver oxide, and copper acetate.

[0017] Preferably, the additive is any one of pivalic acid and sodium 2,4,6-trimethylbenzoate or a combination thereof.

[0018] Preferably, the amount of the trivalent metal catalyst used is 2 mol% of the amount of the N-(1-aryl vinyl)amide compound (Formula II) used.

[0019] Preferably, the reaction is carried out at 120-140° C.; the reaction is carried out for 12-24 hours.

[0020] The preparation method of the polysubstituted oxazole compound in some preferred embodiments of the present patent application comprises the following specific steps:

[0021] S1: In a reactor, 2.5 mg of pentamethylcyclopentadiene iridium dichloride dimer, 3.9 mg of silver trifluoromethanesulfonimide, 69.5 mg of silver oxide, 30.6 mg of pivalic acid, 1.0 mL of toluene solvent, 35.2 mg of N-(1-(2,4-dichlorophenyl)vinyl)propionamide, and 49.8 mg of 2,2'-bithiophene were added in sequence in air;

[0022] S2: reacting the reaction solution at 140°C for 12 hours;

[0023] S3: After the reaction is completed, the mixture is separated by column chromatography to obtain the target compound.

[0024] The present patent application also provides a solar cell, which is a perovskite solar cell, and the hole transport material in the perovskite solar cell is a multi-substituted oxazole compound prepared by the above-mentioned preparation method.

[0025] This patent application realizes multiple dehydrogenation 1,1 difunctionalization of olefins under the conditions of inert solvents by the joint promotion of trivalent metal catalysts and silver salt oxidants: Specifically, firstly, N-(1-aryl vinyl) amide) is used as an easily available and easily converted raw material, and amide is used as a weakly coordinated traceless directing group to realize the C SP2 -H activated arylation, and then the amide undergoes enol tautomerism, and once again undergoes intramolecular oxidative cyclization with the olefin, thereby constructing carbon-carbon bonds and carbon-hetero bonds, and obtaining multiple dehydrogenation 1,1 difunctionalized products of the olefin. This method has high atom economy (the product is obtained by multiple cross-dehydrogenation couplings, and the byproduct is H2O or H2) and step economy (no need to pre-halogenate or metallate the raw materials). It uses nucleophilic reagents that are abundant in nature as raw materials, and the substrate has a wide range of applicability. The simple and easily available N-(1-aryl vinyl) amide is used as a reaction substrate, and at the same time, it participates in the construction of nitrogen-containing fused heterocycles as a traceless directing group. The obtained heterocyclic substrate can be used in the hole transport layer of perovskite solar cells.

[0026] Compared with the prior art, the beneficial effects of this patent application are:

[0027] The preparation method of the polysubstituted oxazole compound provided in the present patent application has the characteristics of easy availability of raw materials, multiple dehydrogenation, efficient atom economy and step economy, and the obtained heterocyclic substrate can be applied to hole transport materials of perovskite solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The hydrogen nuclear magnetic resonance spectrum of compound 1a prepared in Example 1 of the present patent application;

[0029] Figure 2The carbon NMR spectrum of compound 1a prepared in Example 1 of the present patent application;

[0030] Figure 3 This is the hydrogen nuclear magnetic resonance spectrum of compound 1b prepared in Example 2 of this patent application;

[0031] Figure 4 The carbon NMR spectrum of compound 1b prepared in Example 2 of the present patent application;

[0032] Figure 5 The NMR fluorine spectrum of compound 1b prepared in Example 2 of the present patent application;

[0033] Figure 6 This is the hydrogen nuclear magnetic resonance spectrum of compound 1c prepared in Example 3 of this patent application;

[0034] Figure 7 The carbon NMR spectrum of compound 1c prepared in Example 3 of the present patent application;

[0035] Figure 8 This is the hydrogen nuclear magnetic resonance spectrum of compound 1d prepared in Example 4 of this patent application;

[0036] Fig. 9 The carbon NMR spectrum of compound 1d prepared in Example 4 of the present patent application;

[0037] Fig.10 This is the hydrogen nuclear magnetic resonance spectrum of compound 1e prepared in Example 4 of this patent application;

[0038] Fig.11 The carbon NMR spectrum of compound 1e prepared in Example 5 of the present patent application;

[0039] Fig.12 This is the hydrogen nuclear magnetic resonance spectrum of compound 1f prepared in Example 4 of this patent application;

[0040] Fig.13 The carbon NMR spectrum of compound 1f prepared in Example 5 of the present patent application;

[0041] Fig.14 This is the hydrogen nuclear magnetic resonance spectrum of compound 1g prepared in Example 4 of this patent application;

[0042] Fig.15 The carbon NMR spectrum of compound 1g prepared in Example 5 of the present patent application;

[0043] Fig.16 This is the hydrogen nuclear magnetic resonance spectrum of compound 1h prepared in Example 4 of this patent application;

[0044] Fig.17The carbon NMR spectrum of compound 1h prepared in Example 5 of the present patent application;

[0045] Fig.18 This is the hydrogen nuclear magnetic resonance spectrum of compound 1i prepared in Example 4 of this patent application;

[0046] Fig.19 The carbon NMR spectrum of compound 1i prepared in Example 5 of the present patent application;

[0047] Fig. 20 The hydrogen nuclear magnetic resonance spectrum of compound 1j prepared in Example 4 of the present patent application;

[0048] Fig.21 The carbon NMR spectrum of compound 1j prepared in Example 5 of the present patent application;

[0049] Fig. 22 The frontier orbital distribution diagram of compound 1j prepared in Example 5 of the present patent application;

[0050] Fig.23 The normalized UV absorption spectrum and fluorescence emission spectrum of compound 1j prepared in Example 5 of the present patent application;

[0051] Fig.24 This is the cyclic voltammetry scan of compound 1j prepared in Example 5 of this patent application. DETAILED DESCRIPTION

[0052] The embodiments of the present patent application will be described in detail below in conjunction with the examples, but those skilled in the art will appreciate that the following examples are only used to illustrate the present patent application and should not be considered to limit the scope of the present patent application. If the specific conditions are not specified in the examples, they are carried out according to the normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0053] It should be noted that:

[0054] In this patent application, unless otherwise specified, all implementation methods and preferred implementation methods mentioned herein can be combined with each other to form a new technical solution.

[0055] In this patent application, unless otherwise specified, each reaction or operation step can be carried out sequentially or in a sequential manner. Preferably, the reaction method herein is carried out sequentially.

[0056] Unless otherwise specified, the professional and scientific terms used herein are the same as those familiar to those skilled in the art. In addition, any method or material similar or equivalent to the described content may also be applied to this patent application.

[0057] The present patent application provides a method for preparing a polysubstituted oxazole compound: in an inert solvent and under the action of a trivalent metal catalyst, an N-(1-aryl vinyl)amide compound (Formula II) is reacted with an aromatic heterocyclic compound (Formula III) to obtain a polysubstituted oxazole compound (Formula I). ​​The reaction equation in the preparation method is as follows:

[0058]

[0059] Wherein Ar is an o-, m- or p-substituted benzene ring or condensed ring compound; R is a saturated alkane; and Het is a thiophene compound, a polysubstituted indole compound, an electron-rich condensed ring aromatic compound and a benzene ring compound.

[0060] The preparation method disclosed in this patent application achieves the 1,1-dehydrogenation difunctionalization of olefins under trivalent metal catalysis with the assistance of the easily available and traceless weakly coordinating directing group N-(1-aryl vinyl) amide, and directly uses various types of electron-rich aromatic rings as coupling reagents to construct a polycyclic aromatic heterocyclic molecular skeleton.

[0061] Based on this, the patent applicant also simply synthesized a material molecule based on diphenylamine synthetic building blocks through the dehydrogenation 1,1-difunctionalization strategy of olefins. According to the frontier orbital distribution diagram obtained by DFT calculation, it was found that its energy level matched the perovskite solar hole transport material. After performance characterization such as ultraviolet absorption, fluorescence emission, and cyclic voltammetry scanning, it was further verified that the material molecule met the requirements of the hole transport layer of the perovskite solar cell.

[0062] Next, the preparation method of the polysubstituted oxazole compound of the present patent application is described in detail with specific examples.

[0063] 1. Preparation Example

[0064] Example 1 5-([2,2'-bithiophene]-5-yl)-4-(2,4-dichlorophenyl)-2-ethyloxazole (1a)

[0065] Under an atmospheric pressure air atmosphere, N-(1-(2,4-dichlorophenyl)vinyl)propionamide 2a (35.2 mg, 0.20 mmol), trivalent iridium catalyst [Cp*IrCl2]2 (2.5 mg, 0.004 mmol), 2,2'-bithiophene 3a (49.8 mg, 0.30 mmol), silver trifluoromethanesulfonimide (3.9 mg, 0.01 mmol), silver oxide (69.5 mg, 0.30 mmol), pivalic acid (30.6 mg, 0.30 mmol), and toluene (Tol, 1.0 mL) were added sequentially into a 15 mL Schlenk reaction tube and reacted at 140 °C for 12 hours. The crude product was separated by chromatography using the prepared silica gel plate, and the selected developing solvent or eluent was a volume ratio of petroleum ether to ethyl acetate of 20:1, and the product 5-([2,2'-bithiophene]-5-yl)-4-(2,4-dichlorophenyl)-2-ethyloxazole (1a) was obtained with a yield of 72%. The chemical reaction equation corresponding to this example is as follows:

[0066]

[0067] The H NMR and C NMR spectra of the compound prepared in Example 1 are as follows: Figure 1 and Figure 2 As shown. Figure 1 It can be seen that: 1 H NMR (400MHz, CDCl3) δ7.53 (d, J = 2.1Hz, 1H), 7.45 (d, J = 8.2Hz, 1H), 7.34 (dd, J = 2.1Hz, 8.3Hz, 1H), 7.21 (dd, J = 1.1Hz, 5.1Hz, 1H), 7.13 (dd, J = 1.1Hz, 3.7Hz, 1H), 7.03 (d, J = 3.9Hz, 1H), 6.99 (dd, J = 3.6Hz, 5.1Hz, 1H), 6.93 (d, J = 3.8Hz, 1H), 2.93–2.86 (m, 2H), 1.42 (dd, J = 5.2Hz, 8.2Hz, 3H). The molecular hydrogen spectrum peaks can correspond to the target product one by one, and the quantity is reasonable. Figure 2 It can be seen 13C NMR (100MHz, CDCl3) δ164.3, 142.6, 137.9, 136.6, 135.5, 135.2, 132.9, 130.9, 130.0, 129.8, 129.1, 128.2, 128.2, 127.9, 127.5, 125.4, 125.3, 125.0, 124.2, 124.1, 21.7, 11.2. The molecular carbon spectrum peaks can correspond to the target product one by one, and the quantity is reasonable. Combined with the results of the above nuclear magnetic hydrogen spectrum and carbon spectrum, it can be seen that the product obtained in Example 1 is 5-([2,2'-bithiophene]-5-yl)-4-(2,4-dichlorophenyl)-2-ethyloxazole (1a).

[0068] In this example, N-(1-(2,4-dichlorophenyl)vinyl)propionamide 2a and electron-rich aromatic compound 2,2'-bithiophene 3a were subjected to multiple cross-dehydrogenation coupling reactions to obtain a polysubstituted oxazole compound 5-([2,2'-bithiophene]-5-yl)-4-(2,4-dichlorophenyl)-2-ethyloxazole (1a).

[0069] The polysubstituted oxazole compound synthesis reaction in this embodiment has efficient atomic and step economy, and directly uses the common and readily available nucleophilic reagent N-(1-(2,4-dichlorophenyl)vinyl)propionamide 2a as a raw material, while participating in the construction of nitrogen-containing fused heterocycles as a traceless directing group, and the entire conversion avoids the participation of aryl halides and aryl metal reagents as active sites in the reaction. In addition, the chemical conversion in this embodiment uses the synthetic building block bithiophene (2,2'-bithiophene 3a) as a raw material, which can be applied to the fields of organic optoelectronic materials.

[0070] Example 2 2-Methyl-5-(5-methylthiophen-2-yl)-4-(4-(trifluoromethyl)phenyl)oxazole (1b)

[0071] Under an atmospheric pressure air atmosphere, N-(1-(4-(trifluoromethyl)phenyl)vinyl)acetamide 2b (45.8 mg, 0.20 mmol), 5-methylthiophene 3b (29.4 mg, 0.30 mmol), trivalent rhodium catalyst [Cp*Rh(CH3CN)3Cl2]2 (3.3 mg, 0.004 mmol), silver trifluoromethanesulfonimide (3.9 mg, 0.01 mmol), silver oxide (69.5 mg, 0.30 mmol), pivalic acid (30.6 mg, 0.30 mmol), and toluene (1.0 mL) were added sequentially to a 15 mL Schlenk reaction tube and reacted at 140 °C for 12 hours. The crude product was separated by chromatography using the prepared silica gel plate, and the selected developing solvent or eluent was a volume ratio of petroleum ether to ethyl acetate of 10:1, and the product 2-methyl-5-(5-methylthiophen-2-yl)-4-(4-(trifluoromethyl)phenyl)oxazole (1b) was obtained with a yield of 65%. The chemical reaction equation corresponding to this example is as follows:

[0072]

[0073] The NMR hydrogen spectrum, NMR carbon spectrum and NMR fluorine spectrum of the compound prepared in Example 2 are as follows: Figure 3 , Figure 4 and Figure 5 As shown. Figure 3 It can be seen that: 1 H NMR (400MHz, CDCl3) δ7.58 (d, J = 6.7Hz, 1H), 7.38 (d, J = 5.2Hz, 1H), 7.33 (d, J = 8.9Hz, 1H), 7.23 (s, 1H), 7.19 (dd, J = 5.3Hz, 0.7Hz, 1H), 2.58 (s, 3H). The molecular hydrogen spectrum peaks can correspond to the target product one by one, and the quantity is reasonable. Figure 4 It can be seen that: 13 C NMR (100MHz, CDCl3) δ160.2, 156.8 (d, J = 250.0Hz), 143.3, 139.5, 132.5, 131.6, 131.1, 130.6, 130.4, 129.8, 128.5, 119.7, 119.5, 119.3, 117.2, 13.9. The molecular carbon spectrum peaks can correspond to the target product one by one, and the quantity is reasonable. Figure 5 It can be seen that: 19 F NMR (300MHz, CDCl3) δ-118.2. Combining the results of the above nuclear magnetic hydrogen spectrum, carbon spectrum and fluorine spectrum, it can be seen that the product prepared in Example 2 is 2-methyl-5-(5-methylthiophen-2-yl)-4-(4-(trifluoromethyl)phenyl)oxazole (1b).

[0074] In this embodiment, the acetylamino group in N-(1-(4-(trifluoromethyl)phenyl)vinyl)acetamide 2b is used as a reaction substrate with a traceless directing group, and the electron-rich aromatic ring 5-methylthiophene 3b is used as a coupling reagent. Under the catalysis of the trivalent iridium catalyst [Cp*IrCl2]2, the 1,1-dehydrogenation difunctionalization of olefins is achieved, and the polycyclic aromatic heterocyclic molecular skeleton 2-methyl-5-(5-methylthiophene-2-yl)-4-(4-(trifluoromethyl)phenyl)oxazole (1b) is constructed. The chemical transformation in this embodiment has efficient step economy and atom economy, and is compatible with the fluorine element widely used in the fields of materials and medicine.

[0075] Example 3 Methyl 4-(5-([2,2:5',2'-terthiophene]-5-yl)-2-methyloxazol-4-yl)benzoate (1c)

[0076] Under an atmospheric pressure air atmosphere, methyl 4-(1-acetamidovinyl)benzoate 2c (43.8 mg, 0.20 mmol), 2,2':5,2'-terthiophene 3c (74.4 mg, 0.30 mmol), trivalent iridium catalyst [Cp*IrCl2]2 (2.5 mg, 0.004 mmol), silver trifluoromethanesulfonimide (3.9 mg, 0.01 mmol), silver oxide (69.5 mg, 0.30 mmol), pivalic acid (30.6 mg, 0.30 mmol), and ethylene glycol dimethyl ether (DME, 1.0 mL) were added sequentially into a 15 mL Schlenk reaction tube and reacted at 140 °C for 12 hours. The crude product was separated by chromatography using the prepared silica gel plate, and the selected developing solvent or eluent was a volume ratio of petroleum ether to ethyl acetate of 10:1, and the product 4-(5-([2,2:5',2'-terthiophene]-5-yl)-2-methyloxazol-4-yl)benzoic acid methyl ester (1c) was obtained with a yield of 61%. The chemical reaction equation corresponding to this example is as follows:

[0077]

[0078] The H NMR spectrum and C NMR spectrum of the compound prepared in Example 3 are as follows: Figure 6 and Figure 7 As shown. Figure 6 It can be seen that: 1H NMR (400MHz, CDCl3) δ7.74 (d, J = 8.4Hz, 2H), 7.49 (d, J = 8.4Hz, 2H), 7.23 (d, J = 5.1Hz, 1H), 7.19 (dd, J = 6.0Hz, 3.9Hz, 2H), 7.08 (d, J = 4.0Hz, 3H), 7.03 (dd, J = 5.0Hz, 3.7Hz, 1H), 2.54 (s, 3H). The molecular hydrogen spectrum peaks can correspond to the target product one by one, and the quantity is reasonable from Figure 7 It can be seen that: 13 CNMR (100MHz, CDCl3) δ 160.4, 140.5, 138.3, 137.7, 136.9, 135.2, 134.4, 131.3, 130.4, 129.5, 128.4, 127.9, 126.6, 124.8, 124.7, 124.4, 123.9, 123.8, 94.0, 13.9. The molecular carbon spectrum peaks can correspond to the target product one by one, and the quantity is reasonable. Combined with the results of the above nuclear magnetic hydrogen spectrum and carbon spectrum, it can be seen that the product obtained in Example 3 is methyl 4-(5-([2,2:5', 2'-trithiophene]-5-yl)-2-methyloxazol-4-yl)benzoate (1c).

[0079] The synthesis reaction in this embodiment has high atom economy and step economy, and uses the electron-rich aromatic heterocyclic nucleophile 2,2':5,2'-terthiophene 3c which is abundant in nature as a raw material, and (4-(1-acetamidovinyl)benzoic acid methyl ester 2c as a reaction substrate, while also participating in the construction of the nitrogen-containing fused heterocycle as a traceless directing group. The entire transformation avoids the use of aromatic halides and aromatic metal reagents, which meets the development requirements of sustainable chemistry.

[0080] The chemical conversion in this embodiment uses terthiophene as a raw material. Terthiophene has multiple functions. It is a monomer precursor of polythiophene, a photosensitizer, a polycarbonate dopant, and a very important chemical intermediate. The product synthesized in this embodiment can be applied to various material fields such as electronic liquid crystals and organic electroluminescence.

[0081] Example 4 5-(Benzothiophen-2-yl)-4-(2,4-dichlorophenyl)-2-methyloxazole (1d)

[0082] Under an atmospheric pressure air atmosphere, N-(1-(2,4-dichlorophenyl)vinyl)acetamide 2d (45.8 mg, 0.20 mmol), benzothiophene 3d (40.2 mg, 0.30 mmol), trivalent rhodium catalyst [Cp*RhCl2]2 (2.5 mg, 0.004 mmol), silver trifluoromethanesulfonimide (3.9 mg, 0.01 mmol), silver oxide (69.5 mg, 0.30 mmol), pivalic acid (30.6 mg, 0.30 mmol), and toluene (Tol, 1.0 mL) were added sequentially to a 15 mL Schlenk reaction tube and reacted at 140 °C for 12 hours. The crude product was separated by chromatography using the prepared silica gel plate, and the selected developing solvent or eluent was a volume ratio of petroleum ether to ethyl acetate of 20:1, and the product 5-(benzothiophene-2-yl)-4-(2,4-dichlorophenyl)-2-methyloxazole (1d) was obtained with a yield of 49%. The chemical reaction equation corresponding to this example is as follows:

[0083]

[0084] The H NMR spectrum and C NMR spectrum of the compound prepared in Example 4 are as follows: Figure 8 and Fig. 9 As shown. Figure 8 It can be seen that: 1 H NMR (400MHz, CDCl3) δ7.73(t,J=8.8Hz,2H),7.56(d,J=2.1Hz,1H),7.46(d,J=8.3Hz,1H), 7.37(dd,J=8.2Hz,2.1Hz,1H),7.33(dd,J=7.0Hz,1.7Hz,1H),7.31(s,1H),2.61(s,3H). From Fig. 9 It can be seen that: 13 C NMR (100MHz, CDCl3) δ160.6, 139.4, 135.8, 135.3, 132.9, 132.7, 130.0, 129.5, 129.2, 127.4, 127.4, 125.0, 124.8, 123.9, 122.1, 121.0, 120.8, 14.1. Combining the results of the above H NMR spectrum and C NMR spectrum, it can be seen that the product obtained in Example 4 is 5-(benzothiophene-2-yl)-4-(2,4-dichlorophenyl)-2-methyloxazole (1d).

[0085] The chemical synthesis method in this embodiment has atom and step economy, and directly uses the common and readily available electron-rich aromatic heterocyclic nucleophile benzothiophene 3d and as raw materials, and the easily available N-(1-(2,4-dichlorophenyl)vinyl)acetamide 2d amide as a reaction substrate and participates in the construction of nitrogen-containing fused heterocycles as a traceless directing group. .

[0086] The chemical conversion in this embodiment uses benzothiophene, a star molecule in the field of biomedicine and materials, as a raw material, and the synthesized product can be used in the field of materials such as photochromic materials and optical recording media.

[0087] Example 5 5-(5'-bromo-[2,2'-bithiophene]-5-yl)-4-(2,4-dichlorophenyl)-2-methyloxazole (1e)

[0088] Under an atmospheric pressure air atmosphere, N-(1-(2,4-dichlorophenyl)vinyl)acetamide 2d (45.8 mg, 0.20 mmol), 5-bromo-2,2'-bithiophene 3e (73.2 mg, 0.30 mmol), trivalent iridium catalyst [Cp*IrCl2]2 (2.5 mg, 0.004 mmol), silver trifluoromethanesulfonimide (3.9 mg, 0.01 mmol), silver oxide (69.5 mg, 0.30 mmol), sodium 2,4,6-trimethylbenzoate (55.8 mg, 0.30 mmol), and toluene (Tol, 1.0 mL) were added sequentially to a 15 mL Schlenk reaction tube and reacted at 140 °C for 12 hours. The crude product was separated by chromatography using the prepared silica gel plate, and the selected developing solvent or eluent was a volume ratio of petroleum ether to ethyl acetate of 20:1, and the product 5-(5'-bromo-[2,2'-bithiophene]-5-yl)-4-(2,4-dichlorophenyl)-2-methyloxazole (1e) was obtained with a yield of 68%. The chemical reaction equation corresponding to this example is as follows:

[0089]

[0090] The H NMR spectrum and C NMR spectrum of the compound prepared in Example 5 are as follows: Fig.10 and Fig.11 As shown. Fig.10 It can be seen that: 1 H NMR (400MHz, CDCl3) δ7.56(d,J=2.1Hz,1H),7.46(d,J=8.3Hz,1H),7.37(dd,J=8.3Hz,2.1Hz,1 H), 6.97 (dd, J = 7.3Hz, 3.9Hz, 2H), 6.94 (d, J = 3.8Hz, 1H), 6.88 (d, J = 3.9Hz, 1H), 2.60 (s, 3H). From Fig.11It can be seen that: 13 C NMR (100MHz, CDCl3) δ160.1, 142.7, 138.0, 136.8, 135.7, 135.1, 132.8, 131.2, 130.7, 130.0, 129.5, 129.0, 127.5, 125.5, 124.3, 124.2, 111.6, 13.9. Combining the results of the above H NMR spectrum and C NMR spectrum, it can be seen that the product obtained in Example 5 is 5-(5'-bromo-[2,2'-bithiophene]-5-yl)-4-(2,4-dichlorophenyl)-2-methyloxazole (1e).

[0091] In this embodiment, multiple dehydrogenation 1,1 difunctionalization of olefins is achieved under the conditions of inert solvent toluene, by the co-promotion of trivalent iridium catalyst [Cp*IrCl2]2 and silver oxide. This method has high atom economy and step economy, and uses the naturally abundant nucleophilic reagent 5-bromo-2,2'-bithiophene 3e as a raw material, and the substrate has a wide range of applicability. The simple and easily available N-(1-(2,4-dichlorophenyl)vinyl)acetamide 2d is used as a reaction substrate, and at the same time, it participates in the construction of nitrogen-containing polysubstituted oxazole compounds as a traceless directing group.

[0092] The chemical transformation in this embodiment is compatible with a variety of aryl halide groups that are difficult to be compatible with conventional carbon-hydrogen bond activation reactions. Aryl halide groups have good chemical activity, such as palladium-catalyzed coupling reactions, Ullmann coupling reactions, etc., thereby providing a platform for the construction of more complex molecules.

[0093] Example 6 4-(2,4-dichlorophenyl)-2-methyl-5-(1-methyl-2-phenyl-1H-indol-3-yl)oxazole (1f)

[0094] Under an atmospheric pressure air atmosphere, N-(1-(2,4-dichlorophenyl)vinyl)acetamide 2d (45.8 mg, 0.20 mmol), 1-methyl-2-phenyl-1H-indole 3f (62.2 mg, 0.30 mmol), trivalent rhodium catalyst [Cp*RhCl2]2 (2.5 mg, 0.004 mmol), silver hexafluoroantimonate (3.6 mg, 0.01 mmol), silver oxide (69.5 mg, 0.30 mmol), pivalic acid (30.6 mg, 0.30 mmol), and toluene (Tol, 1.0 mL) were added sequentially to a 15 mL Schlenk reaction tube and reacted at 140 °C for 12 hours. The crude product was separated by chromatography using the prepared silica gel plate, and the selected developing solvent or eluent was a volume ratio of petroleum ether to ethyl acetate of 10:1, and the product 4-(2,4-dichlorophenyl)-2-methyl-5-(1-methyl-2-phenyl-1H-indol-3-yl)oxazole (1f) was obtained with a yield of 65%. The chemical reaction equation corresponding to this example is as follows:

[0095]

[0096] The H-NMR spectrum and C-NMR spectrum of the compound prepared in Example 6 are as follows: Fig.12 and Fig.13 As shown. Fig.12 It can be seen that: 1 H NMR (400MHz, CDCl3) δ7.76(d,J=7.9Hz,1H),7.42(d,J=8.2Hz,1H),7.38-7.34(m,1H),7.30-7.27(m,2H),7.25-7.24( m,1H),7.23-7.20(m,2H),7.13(d,J=1.8Hz,1H),7.04-7.01(m,2H),6.93(d,J=1.9Hz,1H),3.61(s,3H),2.61(s,3H).From Fig.13 It can be seen that: 13 C NMR (100MHz, CDCl3) δ160.3, 144.3, 140.2, 137.7, 137.3, 133.9, 133.3, 132.3, 130.5, 130.3, 129.8, 129.2, 128.9, 128.2, 126.4, 125.2, 122.6, 120.8, 119.9, 109.7, 102.1, 30.9, 14.0. Combining the results of the above H NMR and C NMR spectra, it can be seen that the product obtained in Example 6 is 4-(2,4-dichlorophenyl)-2-methyl-5-(1-methyl-2-phenyl-1H-indol-3-yl)oxazole (1f).

[0097] In this embodiment, multiple dehydrogenation 1,1 difunctionalization of olefins is achieved under the conditions of inert solvent toluene, by the co-promotion of trivalent iridium catalyst [Cp*IrCl2]2 and silver oxide. This method has high atom economy and step economy, and uses the electron-rich aromatic heterocyclic nucleophile 1-methyl-2-phenyl-1H-indole 3f, which is abundant in nature, as a raw material. The substrate has a wide range of applications, and the simple and easily available N-(1-(2,4-dichlorophenyl)vinyl)acetamide 2d is used as a reaction substrate, and at the same time, it participates in the construction of multi-substituted oxazole compounds as a traceless directing group.

[0098] The chemical transformation in this embodiment can modify indole compounds with high biological activity and containing easily convertible halogen functional groups, thereby providing a platform for the construction of more complex molecules.

[0099] Example 7 4-(4-Bromophenyl)-2-methyl-5-(1-methyl-1H-indol-3-yl)oxazole (1 g)

[0100] Under an atmospheric pressure air atmosphere, N-(1-(4-bromophenyl)vinyl)acetamide 2e (47.8 mg, 0.20 mmol), 1-methyl-1H-indole 3g (39.3 mg, 0.30 mmol), trivalent iridium catalyst [Cp*IrCl2]2 (2.5 mg, 0.004 mmol), silver trifluoromethanesulfonimide (3.9 mg, 0.01 mmol), silver oxide (69.5 mg, 0.30 mmol), pivalic acid (30.6 mg, 0.30 mmol), and toluene (Tol, 1.0 mL) were added sequentially to a 15 mL Schlenk reaction tube and reacted at 140 ° C for 12 hours. The crude product was separated by chromatography on a prepared silica gel plate, and the selected developing solvent or eluent was a volume ratio of petroleum ether to ethyl acetate of 10:1, and the product 4-(4-bromophenyl)-2-methyl-5-(1-methyl-1H-indol-3-yl)oxazole (1 g) was obtained with a yield of 65%. The chemical reaction equation corresponding to this example is as follows:

[0101]

[0102] The H-NMR spectrum and C-NMR spectrum of the compound prepared in Example 7 are as follows: Fig.14 and Fig.15 As shown. Fig.14 It can be seen that: 1H NMR (400MHz, CDCl3) δ7.76(d,J=7.9Hz,1H),7.42(d,J=8.2Hz,1H),7.38-7.34(m,1H),7.30-7.27(m,2H),7.25-7.24( m,1H),7.23-7.20(m,2H),7.13(d,J=1.8Hz,1H),7.04-7.01(m,2H),6.93(d,J=1.9Hz,1H),3.61(s,3H),2.61(s,3H).From Fig.15 It can be seen that: 13 C NMR (100MHz, CDCl3) δ160.3, 144.3, 140.2, 137.7, 137.3, 133.9, 133.3, 132.3, 130.5, 130.3, 129.8, 129.2, 128.9, 128.2, 126.4, 125.2, 122.6, 120.8, 119.9, 109.7, 102.1, 30.9, 14.0. Combining the results of the above nuclear magnetic hydrogen spectrum and carbon spectrum, it can be seen that the product obtained in Example 7 is 4-(4-bromophenyl)-2-methyl-5-(1-methyl-1H-indol-3-yl)oxazole (1g).

[0103] In this embodiment, multiple dehydrogenation 1,1 difunctionalization of olefins is achieved under the conditions of inert solvent toluene, by the co-promotion of trivalent iridium catalyst [Cp*IrCl2]2 and silver oxide. This method has high atom economy and step economy. The entire transformation avoids the participation of aryl halides and aryl metal reagents as active sites in the reaction, and uses the electron-rich aromatic heterocyclic nucleophile 1-methyl-1H-indole 3g, which is abundant in nature, as a raw material. The substrate has a wide range of applications. The simple and easily available N-(1-(4-bromophenyl)vinyl)acetamide 2e is used as a reaction substrate and participates in the construction of multi-substituted oxazole compounds as a traceless directing group.

[0104] Example 8 2-Methyl-5-(1-methyl-1H-indol-3-yl)-4-(naphthalen-2-yl)oxazole (1h)

[0105] Under an atmospheric pressure air atmosphere, N-(1-(naphthalene-2-yl)vinyl)acetamide 2f (42.4 mg, 0.20 mmol), 1-methyl-1H-indole 3g (39.3 mg, 0.30 mmol), trivalent iridium catalyst [Cp*IrCl2]2 (2.5 mg, 0.004 mmol), silver hexafluoroantimonate (3.6 mg, 0.01 mmol), silver oxide (69.5 mg, 0.30 mmol), pivalic acid (30.6 mg, 0.30 mmol), and toluene (Tol, 1.0 mL) were added sequentially to a 15 mL Schlenk reaction tube and reacted at 140°C for 12 hours. The crude product was separated by chromatography on a prepared silica gel plate, and the selected developing solvent or eluent was a volume ratio of petroleum ether to ethyl acetate of 10:1, and the product 2-methyl-5-(1-methyl-1H-indol-3-yl)-4-(naphthalene-2-yl)oxazole (1h) was obtained with a yield of 63%. The chemical reaction equation corresponding to this example is as follows:

[0106]

[0107] The H-NMR and C-NMR spectra of the compound prepared in Example 8 are as follows: Fig.16 and Fig.17 As shown. Fig.16 It can be seen that: 1 HNMR (400MHz, CDCl3) δ8.26 (s, 1H), 7.79 (dd, J = 3.3Hz, 6.2Hz, 2H), 7.73 (d, J = 2.1Hz, 1H), 7.56 (d, J = 8.0Hz, 1H), 7.4 4(dd,J=3.2Hz,6.2Hz,2H),7.41-7.35(m,3H),7.31-7.29(m,1H),7.10(t,J=1.1Hz,1H),3.83(s,3H),2.64(s,3H). From Fig.17 It can be seen that: 13 C NMR (100MHz, CDCl3) δ160.0, 142.3, 136.9, 133.5, 133.2, 132.7, 129.8, 128.2, 128.2, 127.9, 127.6, 126.1, 126.0, 125.9, 125.8, 125.1, 122.5, 121.1, 120.5, 109.6, 103.9, 33.1, 14.1. Combining the results of the above nuclear magnetic hydrogen spectrum and carbon spectrum, it can be seen that the product obtained in Example 8 is 2-methyl-5-(1-methyl-1H-indol-3-yl)-4-(naphthalene-2-yl)oxazole (1h).

[0108] In this embodiment, multiple dehydrogenation 1,1 difunctionalization of olefins is achieved under the conditions of inert solvent toluene, by the co-promotion of trivalent iridium catalyst [Cp*IrCl2]2 and silver oxide. This method has high atom economy and step economy, and uses the electron-rich aromatic heterocyclic nucleophile 1-methyl-1H-indole 3g, which is abundant in nature, as a raw material. The substrate has a wide range of applications, and the easily available N-(1-(naphthalene-2-yl)vinyl)acetamide 2f is used as a reaction substrate, and participates in the construction of nitrogen-containing fused heterocycles as a traceless directing group.

[0109] The chemical transformation in this embodiment can be applied to fused ring materials and bioactive molecules.

[0110] Example 9 3-(4-(2,4-dichlorophenyl)-2-methyloxazol-5-yl)-10-methyl-10H-phenoxazine (1i)

[0111] Under an atmospheric pressure air atmosphere, N-(1-(2,4-dichlorophenyl)vinyl)acetamide 2d (45.8 mg, 0.20 mmol), 10-methyl-10H-phenoxazine 3h (59.2 mg, 0.30 mmol), trivalent iridium catalyst [Cp*IrCl2]2 (2.5 mg, 0.004 mmol), silver trifluoromethanesulfonimide (3.9 mg, 0.01 mmol), silver carbonate (82.5 mg, 0.30 mmol), sodium 2,4,6-trimethylbenzoate (55.8 mg, 0.30 mmol), and toluene (Tol, 1.0 mL) were added sequentially to a 15 mL Schlenk reaction tube and reacted at 140 °C for 12 hours. The crude product was separated by chromatography using the prepared silica gel plate, and the selected developing solvent or eluent was a volume ratio of petroleum ether to ethyl acetate of 10:1, and the product 3-(4-(2,4-dichlorophenyl)-2-methyloxazol-5-yl)-10-methyl-10H-phenoxazine (1i) was obtained with a yield of 46%. The chemical reaction equation corresponding to this example is as follows:

[0112]

[0113] The H-NMR spectrum and C-NMR spectrum of the compound prepared in Example 9 are shown in the following order: Fig.18 and Fig.19 As shown. Fig.18 It can be seen that: 1H NMR (400MHz, CDCl3) δ7.51(d,J=2.1Hz,1H),7.41(d,J=8.3Hz,1H),7.32(dd,J=2.1Hz,8.3Hz,1H),6.86–6.80 (m,2H),6.73–6.67(m,3H),6.52(dd,J=1.3Hz,7.9Hz,1H),6.42(d,J=8.4Hz,1H),3.04(s,3H),2.55(s,3H). From Fig.19 It can be seen that: 13 C NMR (100MHz, CDCl3) δ159.5, 145.5, 135.0, 134.9, 132.8, 130.7, 130.0, 129.1, 128.2, 127.5, 126.9, 125.3, 123.9, 123.6, 123.3, 121.4, 121.0, 116.3, 113.9, 111.6, 111.3, 14.0. Combining the results of the above H NMR and C NMR spectra, it can be seen that the product obtained in Example 9 is 3-(4-(2,4-dichlorophenyl)-2-methyloxazol-5-yl)-10-methyl-10H-phenoxazine (1i).

[0114] In this embodiment, multiple dehydrogenation 1,1 difunctionalization of olefins is achieved under the conditions of inert solvent toluene, by the co-promotion of trivalent iridium catalyst [Cp*IrCl2]2 and silver carbonate. This method has high atom economy and step economy, and uses the electron-rich aromatic heterocyclic nucleophile 10-methyl-10H-phenoxazine 3h, which is abundant in nature, as a raw material. The substrate has a wide range of applications. The simple and easily available N-(1-(2,4-dichlorophenyl)vinyl)acetamide 2d is used as a reaction substrate and participates in the construction of multi-substituted oxazole compounds as a traceless directing group.

[0115] The chemical conversion in this embodiment uses the synthetic material intermediate phenoxazine as a raw material and can be applied to the fields of organic optoelectronic materials.

[0116] Example 10 4-(4-(2,4-dichlorophenyl)-2-methyloxazol-5-yl)-N,N-diphenylaniline (1j)

[0117] Under an atmospheric pressure air atmosphere, N-(1-(2,4-dichlorophenyl)vinyl)acetamide 2d (45.8 mg, 0.20 mmol), triphenylamine 3c (73.6 mg, 0.30 mmol), trivalent iridium catalyst [Cp*IrCl2]2 (2.5 mg, 0.004 mmol), silver trifluoromethanesulfonimide (3.9 mg, 0.01 mmol), silver oxide (69.5 mg, 0.30 mmol), pivalic acid (30.6 mg, 0.30 mmol), and ethylene glycol dimethyl ether (DME, 1.0 mL) were added sequentially into a 15 mL Schlenk reaction tube and reacted at 140 °C for 12 hours. The crude product was separated by chromatography using the prepared silica gel plate, and the selected developing solvent or eluent was a volume ratio of petroleum ether to ethyl acetate of 10:1, and the product 4-(4-(2,4-dichlorophenyl)-2-methyloxazol-5-yl)-N,N-diphenylaniline (1j) was obtained with a yield of 53%. The chemical reaction equation corresponding to this example is as follows:

[0118]

[0119] The H-NMR spectrum and C-NMR spectrum of the compound prepared in Example 10 are shown in the following order: Fig. 20 and Fig.21 As shown. Fig. 20 It can be seen that: 1 H NMR(400MHz, CDCl3)δ7.48(d,J=2.1Hz,1H),7.40(d,J=8.3Hz,1H),7.30–7.27(m,2H),7.2 3–7.16(m,5H),7.10–7.06(m,4H),7.06–7.02(m,2H),6.96(d,J=8.8Hz,2H),2.55(s,3H). Fig.21 It can be seen that: 13 CNMR (100MHz, CDCl3) δ159.6,147.9,147.2,147.0,135.0,135.0,132.8,131.0,130.2,130.2,129.9,129.4,129.1,128 .5,128.3,127.6,127.4,126.9,126.4,125.9,125.3,125.0,123.6,122.3,121.6,114.3,108.5,77.4,77.1,76.8,14.1. Combining the results of the above H-NMR spectrum and C-NMR spectrum, it can be seen that the product obtained in Example 10 is 4-(4-(2,4-dichlorophenyl)-2-methyloxazol-5-yl)-N,N-diphenylaniline (1j).

[0120] In this embodiment, multiple dehydrogenation 1,1 difunctionalization of olefins is achieved under the conditions of inert solvent ethylene glycol dimethyl ether, by the co-promotion of trivalent iridium catalyst [Cp*IrCl2]2 and silver oxide. This method has high atom economy and step economy. The entire transformation avoids the participation of aryl halides and aryl metal reagents as active sites in the reaction, and uses triphenylamine 3j, an electron-rich aromatic heterocyclic nucleophile abundant in nature, as a raw material. The substrate has a wide range of applications. The simple and easily available N-(1-(2,4-dichlorophenyl)vinyl)acetamide 2d is used as a reaction substrate and participates in the construction of multi-substituted oxazole compounds as a traceless directing group.

[0121] 2. Application examples

[0122] When characterizing the material of 1j molecule, we found that it exhibited good hole transport material properties. Specifically, Fig. 22 It is known that the highest occupied molecular orbital (HOMO) of 1j is delocalized in the entire molecule, which is beneficial to charge transfer, and the lowest unoccupied molecular orbital (LUMO) is mainly located on the core skeleton. The overlap of the HOMO orbital and the LUMO orbital is beneficial to hole extraction. The E of 1j calculated by density functional theory (DFT) is HOMO or E LUMO The value is -5.05 / -1.33eV, which meets the requirements of hole transport materials for perovskite solar cells.

[0123] When characterizing the UV absorption and fluorescence emission of 1j molecules, Fig.23 It can be seen that its maximum ultraviolet absorption wavelength is 341nm, and the maximum fluorescence emission wavelength is 461nm, and then E is estimated. 0-0 is 3.12eV; Fig.24 It can be concluded that the actual HOMO value is -5.09eV; thus, the actual LUMO value is -1.97eV, which is consistent with the value obtained by DFT calculation. The above characterization can further verify the feasibility of 1j molecules as perovskite solar cells.

[0124]

[0125] Note: a) is CV measurement. Ferrocene is used as external standard to obtain the actual HOMO value from the oxidation onset potential; b) is E LUMO Calculate = E HOMO +E 0-0 . Where E 0-0 Estimated by the intersection of normalized UV absorption and fluorescence emission spectra; c) estimated by DFT calculation.

[0126] In the above, multi-substituted oxazole compounds are obtained by multiple cross-dehydrogenation coupling reactions of trivalent metal-catalyzed N-(1-aryl vinyl)amides with four different electron-rich aromatic rings; specifically, under inert solvent conditions, multiple dehydrogenation 1,1-difunctionalization of olefins is achieved by the joint promotion of trivalent metal catalysts and silver salt oxidants. This method has atomic and step economy, and directly uses common and readily available nucleophilic reagents as raw materials, which meets the development requirements of sustainable chemistry; the substrates of this transformation have a wide range of applications, and the simple and readily available N-(1-aryl vinyl)amide is used as a reaction substrate, while participating as a traceless directing group in the construction of nitrogen-containing fused heterocycles; in addition, the obtained heterocyclic substrate is also used in the hole transport layer of perovskite solar cells.

[0127] In summary, this patent application involves a multiple dehydrogenation 1,1-difunctionalization reaction of N-(1-aryl vinyl) amide catalyzed by a trivalent metal catalyst with various types of nucleophiles such as thiophene, indole, and aromatic hydrocarbons, thereby realizing the construction of nitrogen-containing fused heterocycles, and then developing its application in the field of optoelectronic materials. Specifically, under the conditions of an inert solvent, the multiple dehydrogenation 1,1 difunctionalization of olefins is achieved by the joint promotion of a trivalent metal catalyst and a silver salt oxidant. This method has high atomic economy and step economy, and uses nucleophiles that are abundant in nature as raw materials. The substrate has a wide range of applications. The simple and easily available N-(1-aryl vinyl) amide is used as a reaction substrate, and at the same time, it participates in the construction of nitrogen-containing fused heterocycles as a traceless directing group; the obtained heterocyclic substrate can be further applied to the hole transport layer of perovskite solar cells. In addition, the 1,1-dehydrogenation difunctionalization reaction of olefins has more potential advantages. The realization of this method can provide a basis for further multifunctionalization of subsequent products, thereby greatly enriching the molecular complexity. It can not only quickly construct polycyclic aromatic heterocyclic skeletons, but also reduce the use of halogenated reagents and metal reagents, providing new ideas for the green and efficient construction of functional drug molecules and material molecules.

[0128] The olefin dehydrogenation 1,1-difunctionalization reaction disclosed in this patent application has good functional group compatibility and wide substrate applicability. It can not only quickly construct polycyclic aromatic heterocyclic skeletons, but also reduce the use of halogenating reagents and metal reagents, providing a new idea for the green and efficient construction of functional drug molecules and material molecules.

[0129] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of this patent application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0130] Although several embodiments of the present patent application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present patent application, and the scope of the present patent application is defined by the claims and their equivalents.

Claims

1. A method for preparing a polysubstituted oxazole compound, characterized in that: In an inert solvent and under the action of a trivalent metal catalyst, the N-(1-aryl vinyl)amide compound represented by formula II is reacted with the aromatic heterocyclic compound represented by formula III to obtain a polysubstituted oxazole compound represented by formula I. The reaction equation is as follows: Wherein, the amount of the trivalent metal catalyst is 3 mol% of the amount of the compound of formula II; The amount of the halide ion extractor is 5 mol% of the amount of the compound of formula II; The additive is any one of pivalic acid and sodium 2,4,6-trimethylbenzoate or a combination thereof; The compound of formula II is selected from any one of the following structural formulas: Het is one of 2,2'-bithiphenyl, 5-methylthienyl, 2,2:5,2'-terthienyl, benzothienyl, 5-bromo-2,2'-bithiphenyl, 1-methyl-2-phenyl-1H-indole, 1-methyl-1H-indolyl, 10-methyl-10H-phenoxazinyl and triphenylamine, The inert solvent is one of toluene and ethylene glycol dimethyl ether; The trivalent metal catalyst is one of: [Cp*Rh(CH3CN)3Cl2]2, [Cp*IrCl2]2, [Cp*RhCl2]2; The halide ion extractor is one of silver hexafluoroantimonate and silver trifluoromethanesulfonimide; The oxidant is one of silver carbonate and silver oxide; The additive is one of pivalic acid and sodium 2,4,6-trimethylbenzoate.

2. The method for preparing a polysubstituted oxazole compound according to claim 1, characterized in that: The reaction was carried out at 140°C; the reaction was carried out for 12 hours.

3. The method for preparing a polysubstituted oxazole compound according to claim 1, characterized in that: The specific steps include: S1: In a reactor, 2.5 mg of pentamethylcyclopentadiene iridium dichloride dimer, 3.9 mg of silver trifluoromethanesulfonimide, 69.5 mg of silver oxide, 30.6 mg of pivalic acid, 1.0 mL of toluene solvent, 35.2 mg of N-(1-(2,4-dichlorophenyl)vinyl)propionamide, and 49.8 mg of 2,2'-bithiophene were added in sequence in air; S2: reacting the reaction solution at 140°C for 12 hours; S3: After the reaction is completed, the mixture obtained in S2 is separated by column chromatography to obtain the target compound.

4. A solar cell, characterized in that: The solar cell is a perovskite solar cell, and the hole transport material in the perovskite solar cell is a multi-substituted oxazole compound prepared by the preparation method according to claim 1, and the structural formula of the substituted oxazole compound is as follows:

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