2-alkyl-1, 2, 3, 4-tetrahydroquinoline compound and synthesis method thereof

Abstract

The invention belongs to the technical field of organic synthesis, and particularly relates to a synthesis method of a 2-alkyl-1, 2, 3, 4-tetrahydroquinoline compound as shown in a formula I. The invention further relates to a preparation method of the 2-alkyl-1, 2, 3, 4-tetrahydroquinoline compound. According to the method, under the nitrogen protection condition, a tetrahydroquinoline compound as shown in a formula II and an olefin compound as shown in a formula III are taken as raw materials, and a C-H bond direct alkylation reaction is realized by adopting a non-metal photocatalytic system under blue light irradiation. The single-step synthesis method has the following advantages: (1) a free radical reaction path is constructed in a reaction system with additives, and a noble metal catalyst and a stoichiometric oxidant are not needed; (2) the limitation of traditional multi-step synthesis is broken through, and atom economy conversion is realized through light energy driving; (3) the reaction conditions are mild, the operation is simple and convenient, and the regioselectivity is excellent. The obtained compound shown in the formula I is stable in structure, can be used as a key skeleton of a natural product, pesticide active molecules and an organic semiconductor material precursor, is particularly suitable for efficiently constructing a 2-alkyl tetrahydroquinoline drug intermediate with biological activity by a one-pot method, and has a remarkable application value in green synthesis and drug process development. # imgabs0 #

Description

Technical Field

[0001] The present invention relates to a 2-alkyl-1,2,3,4-tetrahydroquinoline compound and a method for synthesizing the same, belonging to the field of organic synthesis. Background Art

[0002] The 1,2,3,4-tetrahydroquinoline (THQ) skeleton is a privileged structure in medicinal chemistry, and its 2-alkyl substituted derivatives (such as Angustureine, Guspareine, Galipenine, etc.) have attracted much attention due to their unique biological activities (such as antibacterial, antimalarial, etc.). Currently, the synthesis of 2-alkyl-1,2,3,4-tetrahydroquinoline compounds mainly relies on two strategies: one is to prepare by catalytic hydrogenation of 2-alkylquinoline precursors, but this method requires the pre-synthesis of 2-alkylquinolines, and the acquisition of such raw materials usually relies on multiple steps of reactions (such as metal-catalyzed coupling reactions or radical alkylation reactions), resulting in a long synthetic route and the need for repeated purification of intermediates (Angew. Chem. Int. Ed. 2019, 58, 13666–13699.); meanwhile, the hydrogenation step often requires high-temperature and high-pressure conditions and noble metal catalysts, which not only have high equipment costs but also cause side reactions of sensitive functional groups due to harsh reaction conditions, restricting the substrate scope (Angew. Chem. Int. Ed. 2020, 59, 17408–17412.). The other is to directly perform C-H bond alkylation on the tetrahydroquinoline skeleton. Although such methods reduce the number of reaction steps, they still face problems such as excessive use of oxidants, metal catalyst residues, and difficulties in regioselectivity control. In particular, the radical reaction pathway is prone to produce ortho- or para-competitive alkylation by-products. Therefore, how to directly construct the 2-alkyl-1,2,3,4-tetrahydroquinoline skeleton through a simple, efficient, mild and environmentally friendly method while achieving broad functional group compatibility and high regioselectivity is still a technical bottleneck that has not been broken through in this field. Summary of the Invention

[0003] Therefore, the object of the present invention is to provide a 2-alkyl substituted 1,2,3,4-tetrahydroquinoline compound.

[0004] Another object of the present invention is to provide a method for synthesizing a 2-alkyl substituted 1,2,3,4-tetrahydroquinoline compound, which has the advantages of simple reaction conditions, no need for metal catalysts, convenient operation, high yield and good regioselectivity.

[0005] Thus, a 2-alkyl substituted 1,2,3,4-tetrahydroquinoline compound of the present invention has the general formula of formula I:

[0006]

[0007] Wherein:

[0008] R 1 is selected from hydrogen, alkyl, alkoxy, ester, halogen, aryl, heteroaryl, cyano, and nitro;

[0009] R 2 is selected from alkyl, aryl, and heteroaryl;

[0010] R 3 is selected from aryl, heteroaryl, alkenyl, alkyl, ester, cyano, amide, and sulfonamide;

[0011] R 4 Selected from hydrogen atom, aryl group, heteroaryl group, alkenyl group and alkyl group.

[0012] The present invention also provides a method for synthesizing 2-alkyl substituted 1,2,3,4-tetrahydroquinoline compounds, which comprises the following steps under the irradiation of a non-metallic photocatalyst and blue light:

[0013] (I) adding a tetrahydroquinoline compound, an olefin compound, a photocatalyst, an additive, and an organic solvent into a reaction vessel;

[0014] (II) mixing the reactants thoroughly, irradiating with blue light and heating under nitrogen or argon protection to react;

[0015] (III) Purification to obtain the product.

[0016] Preferably, in the method of the present invention, the general formula of the tetrahydroquinoline compound is Formula II:

[0017]

[0018] in:

[0019] R 1 is selected from hydrogen, alkyl, alkoxy, ester, halogen, aryl, heteroaryl, cyano, and nitro;

[0020] R 2 Selected from alkyl, aryl, and heteroaryl.

[0021] Preferably, in the method of the present invention, the tetrahydroquinoline compounds are selected from: N-phenyltetrahydroquinoline, N-naphthyltetrahydroquinoline, N-phenyl-5-methyltetrahydroquinoline, N-phenyl-6-methyltetrahydroquinoline, N-phenyl-6-methoxytetrahydroquinoline, N-phenyl-6-fluorotetrahydroquinoline, N-phenyl-6-chlorotetrahydroquinoline, N-phenyl-6-bromotetrahydroquinoline, N-phenyl-6-nitrotetrahydroquinoline, N-phenyl-6-cyanotetrahydroquinoline, N-phenyl-6-nitrotetrahydroquinoline, N-phenyl-6-phenyltetrahydroquinoline, N-phenyl-6-methyltetrahydroquinoline carboxylate, N-phenyl-7-methyltetrahydroquinoline, N-phenyl-8-methyltetrahydroquinoline, N-methyltetrahydroquinoline, N-benzyltetrahydroquinoline, N-thienyltetrahydroquinoline, N-pyridyltetrahydroquinoline, N-(4-methylphenyl)tetrahydroquinoline, N-(3-methylphenyl)tetrahydroquinoline, N-(2-methylphenyl)tetrahydroquinoline, N-(3,5-dimethylphenyl)tetrahydroquinoline, N-(4-fluorophenyl)tetrahydroquinoline, N-(4-chlorophenyl)tetrahydroquinoline, N-(4-bromophenyl)tetrahydroquinoline, N-(4-methoxyphenyl)tetrahydroquinoline, N-(2-methoxy)tetrahydroquinoline, N-(2,5-dimethoxyphenyl)tetrahydroquinoline, N-(2-isopropylphenyl)tetrahydroquinoline, N-(4-trifluoromethylphenyl)tetrahydroquinoline.

[0022] Preferably, in the method of the present invention, the general formula of the olefin compounds is III:

[0023]

[0024] Wherein:

[0025] R 3 is selected from aryl, heteroaryl, alkenyl, alkyl, ester group, cyano group, amide, sulfonamide;

[0026] R 4 is selected from a hydrogen atom, aryl, heteroaryl, alkenyl, alkyl.

[0027] Preferably, in the method of the present invention, the olefin compounds are selected from: styrene, 4-methylstyrene, 4-methoxystyrene, 4-fluorostyrene, 4-chlorostyrene, 4-bromostyrene, 4-trifluoromethylstyrene, 4-hydroxystyrene, methyl 4-vinylbenzoate, 4-vinylphenyl pivalate, 4-vinylphenyl benzoate, 4-hydroxystyrene, 2-methylstyrene, 3-methylstyrene, 2-methoxystyrene, 3-methoxystyrene, 1-naphthylethylene, 2-naphthylethylene, 2-vinylpyridine, 2-vinylthiophene, acrylonitrile, methyl acrylate, ethyl acrylate, 2-cyclohexenone, N,N-dimethylacrylamide, stilbene, 2-phenyl-1-propene, 1-phenyl-1,3-butadiene.

[0028] Preferably, in the method of the present invention, the general formula of the non-metallic photocatalyst is IV:

[0029]

[0030] Wherein:

[0031] R 5 is selected from a hydrogen atom, an alkyl group, an alkoxy group, an ester group, a halogen, a cyano group, an acetylamino group, a trifluoromethyl group, an aryl group, a heteroaryl group;

[0032] R 6 is selected from a hydrogen atom, an alkyl group, an alkoxy group, an ester group, a trifluoromethyl group, a halogen, an aryl group, a heteroaryl group.

[0033] Preferably, in the method of the present invention, the non-metallic photocatalyst is selected from one of the following compounds:

[0034]

[0035] Preferably, in the method of the present invention, the additive is an inorganic base or an organic salt, and is selected from one of K3PO4, KOAc, Na3PO4, Na2CO3, NaOAc, Cs2CO 3， potassium bis(3,5-dimethylpyrazol-1-yl)borate (KTp*).

[0036] Preferably, in the method of the present invention, the organic solvent is one of DCM, MeCN, CHCl3, DCE, Acetone, 1,4-Dioxane, DMSO, DMA, DMF, NMP; the amount of the solvent used is: 0 - 2.0 mL.

[0037] Preferably, in the method of the present invention, the molar ratio of the tetrahydroquinoline compound, the olefin compound, the photocatalyst, and the additive is 1.0:1.0 - 3.0:0.01 - 0.2:0.02 - 0.2; the reaction temperature is 20°C - 60°C; the inert gas is nitrogen or argon; the reaction duration is 2 h - 48 h

[0038] The beneficial effects of the present invention compared with the prior art:

[0039] Under the irradiation of blue light by a non-metallic photocatalyst and an additive, the present invention realizes the hydroamination alkylation reaction of tetrahydroquinoline compounds and olefins in a nitrogen atmosphere, and efficiently constructs 2-alkyl-substituted 1,2,3,4-tetrahydroquinoline derivatives in one step. Compared with the traditional method, its core advantages are reflected in:

[0040] (1) The synthesis route is significantly simplified: breaking through the limitation of the prior art relying on multiple steps of reactions (such as pre-synthesizing 2-alkylquinoline and subsequent hydrogenation), and directly completing C(sp 3)-H bond selective alkylation, eliminating the intermediate separation and purification steps, significantly reducing time and equipment costs;

[0041] (2) Mild and controllable reaction conditions: Replacing high temperature and high pressure conditions with blue light, the reaction can be driven at room temperature and atmospheric pressure, avoiding substrate decomposition or side reactions of sensitive functional groups, greatly improving functional group compatibility and having a very wide substrate applicability;

[0042] (3) Outstanding green economy: Without precious metal catalysts or excessive oxidants, only catalytic amounts of organic photosensitizers and cheap additives are required. The reaction system has high atom economy, and the product can meet the purity requirements of pharmaceutical intermediates without complex post-treatment;

[0043] (4) Precise regulation of regioselectivity: Through the photocatalytic radical relay mechanism, high-selectivity alkylation of the α-C(sp 3 )-H site of tetrahydroquinoline is achieved (ortho / para product ratio > 20:1), which is significantly better than traditional radical alkylation methods;

[0044] (5) Wide application compatibility: The obtained 2-alkyl-1,2,3,4-tetrahydroquinoline derivatives can be directly used as key intermediates for pesticides (such as fungicide precursors), pharmaceuticals (such as Galipenine analogs for antimalarial drugs), and bioactive natural products, especially suitable for industrial continuous flow production.

[0045] The present invention will be further described in detail below with reference to the accompanying drawings and examples. Description of the Drawings

[0046] Figure 1 Synthetic route diagram of the compounds of the present invention.

[0047] Figure 1a and 1b NMR spectra of the product of Example 2.

[0048] Figure 2a and 2b NMR spectra of the product of Example 3.

[0049] Figure 3a and 3b NMR spectra of the product of Example 7.

[0050] Figure 4a and 4b NMR spectra of the product of Example 8.

[0051] Figure 5a and 5b NMR spectra of the product of Example 9.

[0052] Among them, a is the hydrogen spectrum and b is the carbon spectrum. Detailed Embodiments

[0053] The present invention will now be further described in detail with reference to the following drawings. These drawings are all simplified schematic diagrams, only illustrating the basic structure of the present invention in a schematic manner, so they only show the components related to the present invention:

[0054]

[0055] Examples 1 - 18

[0056] comprising the following steps:

[0057] ⑴ Add a tetrahydroquinoline compound, an olefin compound, a photocatalyst, an additive, and an organic solvent into a reaction vessel;

[0058] ⑵ After fully mixing the reactants, uniformly heat the reaction vessel (such as by oil bath heating) to the temperature described in Table 1 and irradiate under blue light. The tetrahydroquinoline compound and the olefin compound react in the solvent and continue for the time described in Table 1; it should be noted that the reaction atmosphere is selected to be protected by nitrogen or argon;

[0059] ⑶ Purify after the reaction to obtain the product.

[0060] The reaction conditions are shown in Table 1:

[0061] Table 1: Molar ratios of tetrahydroquinoline compounds, olefin compounds, photocatalysts, additives, solvents, (tetrahydroquinoline compounds, olefin compounds, photocatalysts, additives), reaction temperatures, and reaction times in Examples 1 - 18.

[0062]

[0063]

[0064] Table 2: Conversion rates and products of the reactions in Examples 1 - 18

[0065]

[0066] Perform NMR characterization on the substances in the reaction vessel after step 3. The results of some examples are as follows:

[0067] The NMR data of the product in Example 2 are as follows:

[0068] 1 H NMR(400MHz,Chloroform - d)δ7.33–7.26(m,2H),7.22–7.17(m,2H),7.16–7.11(m,2H),7.10–7.00(m,4H),6.97–6.89(m,1H),6.78–6.67(m,2H),3.79–3.77(m,1H),2.94–2.57(m,4H),2.10–1.87(m,3H),1.83 - 1.74(m,1H). 1313C NMR (100 MHz, Chloroform-d) δ 148.78, 143.37, 140.48, 131.61, 129.75, 129.52, 129.50, 128.55, 126.50, 125.34, 124.55, 123.65, 118.85, 118.48, 58.75, 33.85, 31.97, 24.56, 23.68.

[0069] The NMR data of the product of Example 3 are as follows:

[0070] 1 1H NMR (400 MHz, Chloroform-d) δ 7.94–7.88 (m, 2H), 7.33–7.27 (m, 2H), 7.19–7.12 (m, 4H), 7.09–7.04 (m, 2H), 6.96–6.91 (m, 1H), 6.76–6.67 (m, 2H), 3.89 (s, 3H), 3.81–3.77 (m, 1H), 2.88–2.70 (m, 4H), 2.06 - 1.90 (m, 3H), 1.86–1.79 (m, 1H). 13 13C NMR (100 MHz, Chloroform-d) δ 167.24, 148.78, 147.64, 143.35, 129.84, 129.52, 128.45, 127.94, 126.52, 125.34, 124.54, 123.68, 118.88, 118.52, 58.82, 52.13, 33.57, 32.69, 24.55, 23.67.

[0071] The NMR data of the product of Example 7 are as follows:

[0072] 1 1H NMR (400 MHz, Chloroform-d) δ 7.30 (dd, J=8.4, 7.2 Hz, 2H), 7.18–7.12 (m, 2H), 7.09–7.02 (m, 2H), 6.97–6.91 (m, 1H), 6.78–6.70 (m, 2H), 3.82–3.76 (m, 1H), 3.65 (s, 3H), 2.93–2.74 (m, 2H), 2.55–2.36 (m, 2H), 2.04 - 1.93 (m, 2H), 1.86 - 1.76 (m, 2H). 1313C NMR (100 MHz, Chloroform-d) δ 174.02, 149.29, 143.01, 129.58, 129.47, 126.45, 124.98, 124.91, 123.43, 119.56, 119.34, 58.66, 51.76, 31.06, 27.22, 24.24, 23.42.

[0073] The NMR data of the product of Example 8 are as follows:

[0074] 1 1H NMR (400 MHz, Chloroform-d) δ 7.31–7.24 (m, 2H), 7.15 (s, 2H), 7.09–6.99 (m, 2H), 6.97–6.91 (m, 1H), 6.76 (td, J = 8.0, 7.1, 1.7 Hz, 2H), 3.92 - 3.86 (m, 1H), 2.92 (d, J = 2.4 Hz, 6H), 2.89–2.74 (m, 2H), 2.51–2.36 (m, 2H), 2.06–1.80 (m, 4H). 13 13C NMR (100 MHz, Chloroform-d) δ 172.79, 149.41, 142.87, 129.65, 129.41, 126.35, 125.48, 124.32, 122.98, 119.74, 119.48, 58.58, 37.32, 35.53, 30.21, 27.36, 24.66, 23.51.

[0075] The NMR data of the product of Example 9 are as follows:

[0076] 1 1H NMR (400 MHz, Chloroform-d) δ 7.29–7.18 (m, 8H), 7.18–7.09 (m, 4H), 7.03 (dd, J = 16.0, 7.4 Hz, 2H), 6.95 (dd, J = 13.4, 7.5 Hz, 3H), 6.80–6.70 (m, 2H), 4.06 (dd, J = 9.2, 6.8 Hz, 1H), 3.72 - 3.67 (m, 1H), 2.95 - 2.86 (m, 1H), 2.77 (dt, J = 13.5, 3.2 Hz, 1H), 2.40 (td, J = 8.8, 4.6 Hz, 1H), 2.23 (dt, J = 14.4, 7.4 Hz, 1H), 1.97 - 1.91 (m, 2H). 1313C NMR (100 MHz, Chloroform-d) δ 148.83, 144.64, 144.24, 143.06, 129.59, 129.31, 128.67, 127.95, 126.45, 126.41, 124.87, 124.77, 123.16, 119.05, 118.92, 57.05, 47.95, 37.90, 24.16, 23.43.

[0077] The NMR data of the product of Example 13 are as follows:

[0078] 1 1H NMR (400 MHz, Chloroform-d) δ 8.45 (d, J = 4.1 Hz, 1H), 7.51 (td, J = 7.7, 1.9 Hz, 1H), 7.29–7.23 (m, 1H), 7.19–7.14 (m, 1H), 7.07–7.04 (m, 1H), 7.00–6.93 (m, 4H), 6.78 (dd, J = 8.8, 2.6 Hz, 1H), 6.11 (d, J = 8.8 Hz, 1H), 3.72 (s, 3H), 3.65 (dq, J = 8.8, 4.3 Hz, 1H), 2.91 (dt, J = 16.3, 8.2 Hz, 1H), 2.85–2.63 (m, 3H), 2.08–1.97 (m, 3H), 1.93–1.84 (m, 1H). 13 13C NMR (100 MHz, Chloroform-d) δ 161.94, 156.67, 149.29, 143.63, 136.38, 134.35, 128.56, 127.72, 126.41, 123.49, 122.60, 121.26, 121.06, 120.92, 115.10, 112.72, 57.44, 55.63, 34.76, 32.97, 29.84, 24.27, 24.24.

[0079] The NMR data of the product of Example 15 are as follows:

[0080] 11H NMR (400 MHz, Chloroform-d) δ 8.44 (d, J = 3.1 Hz, 1H), 7.49 (td, J = 7.7, 1.9 Hz, 1H), 7.29–7.14 (m, 2H), 7.09–7.00 (m, 1H), 7.00–6.85 (m, 4H), 6.42 (dd, J = 7.6, 1.7 Hz, 1H), 6.05 (d, J = 1.7 Hz, 1H), 3.73 (s, 3H), 3.67–3.61 (m, 1H), 2.98–2.62 (m, 4H), 2.08 (s, 3H), 2.06–1.98 (m, 3H), 1.95–1.84 (m, 1H). 13 13C NMR (100 MHz, Chloroform-d) δ 162.15, 156.70, 149.19, 144.59, 136.30, 136.13, 134.90, 131.64, 129.01, 127.19, 122.53, 121.09, 120.94, 119.18, 117.50, 114.81, 112.65, 57.33, 55.61, 34.83, 32.86, 24.36, 23.85, 21.50.

[0081] The NMR data of the product of Example 16 are as follows:

[0082] 1 1H NMR (400 MHz, Chloroform-d) δ 8.46 (dt, J = 4.0, 1.0 Hz, 1H), 7.52 (td, J = 7.7, 1.9 Hz, 1H), 7.09–6.99 (m, 3H), 6.92–6.85 (m, 2H), 6.60 (td, J = 7.3, 1.2 Hz, 1H), 6.29 (dd, J = 8.3, 1.2 Hz, 1H), 3.73 (s, 3H), 3.71 (d, J = 4.4 Hz, 1H), 3.68 (s, 3H), 2.96–2.67 (m, 4H), 2.12–2.00 (m, 3H), 2.00–1.85 (m, 1H). 13 13C NMR (100 MHz, Chloroform-d) δ 162.05, 153.98, 150.99, 149.19, 144.63, 136.36, 129.10, 126.63, 122.60, 122.17, 121.01, 117.18, 116.67, 113.70, 111.87, 57.36, 56.30, 55.83, 34.78, 32.89, 24.31, 24.24.

[0083] The NMR data of the product of Example 17 are as follows:

[0084] 1 H NMR (400 MHz, Chloroform-d) δ 8.54–8.45 (m, 1H), 7.54 (td, J = 7.7, 1.9 Hz, 1H), 7.30–7.17 (m, 5H), 7.11–7.03 (m, 2H), 7.00 (d, J = 7.3 Hz, 1H), 6.97–6.89 (m, 1H), 6.56 (t, J = 7.3 Hz, 1H), 6.41 (d, J = 8.2 Hz, 1H), 4.59 (d, J = 17.0 Hz, 1H), 4.45 (d, J = 17.1 Hz, 1H), 3.46–3.41 (m, 1H), 3.03–2.65 (m, 4H), 2.14–1.89 (m, 4H). 13 C NMR (100 MHz, Chloroform-d) δ 161.59, 149.35, 144.48, 139.28, 136.48, 129.05, 128.60, 127.13, 126.74, 126.53, 122.75, 121.66, 121.19, 115.67, 111.84, 57.38, 54.07, 34.85, 31.95, 24.27, 23.62.

[0085] Inspired by the ideal embodiments of the present invention described above, through the above description, relevant staff can, without departing from the technical idea of this invention, make various changes and modifications. The technical scope of this invention is not limited to the content in the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A method for synthesizing 2-alkyl-1,2,3,4-tetrahydroquinoline compounds, characterized in that, It includes the following steps: Under the protection of inert gas, mix the tetrahydroquinoline compound shown in Formula II and the olefin compound shown in Formula III in a molar ratio of 1.0:1.0 - 3.0, add a non-metal photocatalyst, an additive and an organic solvent, and react at 20 - 60 °C for 2 - 48 hours under blue light irradiation. After post-treatment, the 2-alkyl-1,2,3,4-tetrahydroquinoline compound shown in Formula I is obtained; Among them, the structures of Formula I, Formula II, and Formula III are as follows: Among them, in Formula I: R 1 selected from a hydrogen atom, an alkyl group, an alkoxy group, an ester group, a halogen, an aryl group, a heteroaryl group, a cyano group, a nitro group; R 2 selected from alkyl, aryl, heteroaryl; R 3 Selected from aryl, heteroaryl, alkenyl, alkyl, ester group, cyano group, amide, sulfonamide; R 4 Selected from a hydrogen atom, an aryl group, a heteroaryl group, an alkenyl group, and an alkyl group. In Formula II: R 1 It is defined in the same way as formula Ⅰ; R 2 The definition is the same as that in Formula Ⅰ. In Formula III: R 3 It is defined in the same way as Formula Ⅰ; R 4 It is defined in the same way as Formula Ⅰ.

2. The method according to claim 1, wherein The tetrahydroquinoline compounds are selected from: N-phenyltetrahydroquinoline, N-naphthyltetrahydroquinoline, N-phenyl-5-methyltetrahydroquinoline, N-phenyl-6-methyltetrahydroquinoline, N-phenyl-6-methoxytetrahydroquinoline, N-phenyl-6-fluorotetrahydroquinoline, N-phenyl-6-chlorotetrahydroquinoline, N-phenyl-6-bromotetrahydroquinoline, N-phenyl-6-nitrotetrahydroquinoline, N-phenyl-6-cyanotetrahydroquinoline, N-phenyl-6-nitrotetrahydroquinoline, N-phenyl-6-phenyltetrahydroquinoline, N-phenyl-6-tetrahydroquinoline carboxylate methyl ester, N-phenyl-7-methyltetrahydroquinoline, N-phenyl-8-methyltetrahydroquinoline, N-methyltetrahydroquinoline, N-benzyltetrahydroquinoline, N-thienyltetrahydroquinoline, N-pyridyltetrahydroquinoline, N-(4-methylphenyl)tetrahydroquinoline, N-(3-methylphenyl)tetrahydroquinoline, N-(2-methylphenyl)tetrahydroquinoline, N-(3,5-dimethylphenyl)tetrahydroquinoline, N-(4-fluorophenyl)tetrahydroquinoline, N-(4-chlorophenyl)tetrahydroquinoline, N-(4-bromophenyl)tetrahydroquinoline, N-(4-methoxyphenyl)tetrahydroquinoline, N-(2-methoxy)tetrahydroquinoline, N-(2,5-dimethoxyphenyl)tetrahydroquinoline, N-(2-isopropylphenyl)tetrahydroquinoline, N-(4-trifluoromethylphenyl)tetrahydroquinoline.

3. The method according to claim 1, wherein The olefin compounds are selected from: styrene, 4-methylstyrene, 4-methoxystyrene, 4-fluorostyrene, 4-chlorostyrene, 4-bromostyrene, 4-trifluoromethylstyrene, 4-hydroxystyrene, methyl 4-vinylbenzoate, 4-vinylphenyl pivalate, 4-vinylphenyl benzoate, 4-hydroxystyrene, 2-methylstyrene, 3-methylstyrene, 2-methoxystyrene, 3-methoxystyrene, 1-naphthylethylene, 2-naphthylethylene, 2-vinylpyridine, 2-vinylthiophene, acrylonitrile, methyl acrylate, ethyl acrylate, 2-cyclohexenone, N,N-dimethylacrylamide, stilbene, 2-phenyl-1-propene, 1-phenyl-1,3-butadiene.

4. The method according to any one of claims 1-3, characterized in that, The non-metal photocatalyst is one of the compounds with the structure shown in Formula IV: Among them, in Formula IV, R 5 selected from a hydrogen atom, an alkyl group, an alkoxy group, an ester group, a halogen, a cyano group, an acetamido group, a trifluoromethyl group, an aryl group, a heteroaryl group; R 6 selected from a hydrogen atom, an alkyl group, an alkoxy group, an ester group, a trifluoromethyl group, a halogen, an aryl group, and a heteroaryl group.

5. The method according to claim 4, characterized in that The non-metal photocatalyst is selected from one of the following compounds:

6. The method according to any one of claims 2-5, characterized in that, The additive is an inorganic base or an organic salt, and is selected from one of K3PO4, KOAc, Na3PO4, Na2CO3, NaOAc, and potassium bis(3,5-dimethylpyrazol-1-yl)borate (KTp*). 3， ​ 7. The method according to any one of claims 2-6, characterized in that, The organic solvent is one of DCM, MeCN, CHCl3, DCE, Acetone, 1,4-Dioxane, DMSO, DMA, DMF, NMP; the dosage of the solvent is: 0 - 2.0 mL.

8. The method according to any one of claims 2-7, characterized in that, The molar ratio of the tetrahydroquinoline compound, the olefin compound, the photocatalyst, and the additive is 1.0: 1.0 - 3.0: 0.01 - 0.2: 0.02 - 0.2; the reaction temperature is 20°C - 60°C; the inert gas is nitrogen or argon; the reaction duration is 2 h - 48 h.

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