Beta-alkynyl tetrahydropyridine compound and synthesis method thereof

Abstract

The invention belongs to the technical field of organic chemistry, discloses a beta-alkynyl tetrahydropyridine compound and a synthesis method thereof, and aims to solve the technical problem of high cost of a process for synthesizing a beta-alkynyl tetrahydropyridine structure by allene. The preparation method comprises the following steps: dissolving an alkenyl allene compound 1 and a phenyleneimine compound 2 in a solvent, adding copper trifluoromethanesulfonate, and carrying out a heating reaction to obtain the beta-alkynyl tetrahydropyridine compound. The beta-alkynyl tetrahydropyridine compound is prepared through one-step reaction by taking copper trifluoromethanesulfonate as a catalyst, and the method has the advantages of simplicity in operation, mild conditions, wide substrate range and the like, and has an extremely good application prospect.

Description

Technical Field

[0001] The invention belongs to the field of organic synthesis, and in particular relates to a β-alkynyl tetrahydropyridine compound and a synthesis method thereof. Background Art

[0002] β-Alkynyl tetrahydropyridine structure is an important intermediate for the preparation of natural products and drug molecules, so it is necessary to explore a simple synthetic method for this type of structure. Allene is a type of 1,2-propene compound containing cumulative double bonds, which is composed of two adjacent carbon-carbon double bonds and is an important type of synthon. Compared with alkenes, allenes show higher reactivity due to their higher tension. In recent years, allenes have attracted extensive attention from scientific researchers due to their unique reactivity, selectivity, availability and stability. Under the action of transition metals, allenes can undergo various types of addition reactions, thereby achieving a series of efficient constructions of carbon-hydrogen bonds, carbon-carbon bonds and carbon-hetero bonds, and then through subsequent cycloaddition reactions, very useful carbon heterocyclic compounds can be prepared in synthesis. Compared with traditional catalytic systems, transition metal catalysis has higher efficiency, better thermal and chemical stability, and longer catalytic cycle life. Among them, under transition metal catalysis, when metal-activated allenes are captured by nucleophiles, a very important type of reaction intermediate, metal carbene, can be constructed. The previous synthesis method for preparing metal carbenes is mainly produced by metal decomposition of explosive diazo compounds. Due to the high degree of danger, the further application of this method is limited, especially in large-scale practical production. The strategy of using allenes as precursors to construct metal carbenes replaces the method of producing such carbene intermediates from explosive diazo compounds in the previous synthetic route, which makes the production of metal carbene intermediates safer and more efficient. However, this method is still mainly limited to precious metal catalysis (C.-N.Chen, R.-S.Liu, Angew.Chem.Int.Ed.2019,58,9831.). If it can be extended to cheap metal catalysis, it will be of great significance for the development of allene chemistry. Summary of the invention

[0003] In view of the technical problem that the existing allene synthesis of six-membered ring pyridine compounds requires the use of precious metal catalysts with high toxicity, poor stability and high price, the present invention proposes a method for synthesizing β-alkynyl tetrahydropyridine compounds by allene catalysis with low toxicity, good stability and low cost. The synthesis method synthesizes β-alkynyl tetrahydropyridine compounds by cyclization, migration and other series reactions of alkenyl allene compounds and phenylimine compounds, and has the advantages of simple operation, mild conditions, wide substrate range, etc., and has excellent application prospects.

[0004] To achieve the above object, the technical solution of the present invention is implemented as follows:

[0005] A method for synthesizing a β-alkynyl tetrahydropyridine compound comprises the following steps: dissolving an alkenyl alkene compound 1 and a phenylimine compound 2 in a solvent, adding copper trifluoromethanesulfonate, and reacting to obtain a β-alkynyl tetrahydropyridine compound 3;

[0006] Among them, the structural formula of the alkenyl-linked olefin compound 1 is R has an electron-withdrawing group and an electron-donating group; the structural formula of the phenylimide compound 2 is

[0007] Furthermore, the above R is phenyl or substituted phenyl, and the substituent on the benzene ring of the substituted phenyl is fluorine, chlorine, trifluoromethyl or methyl.

[0008] Furthermore, the above substituent is at the para position or meta position of the benzene ring.

[0009] The reaction equation for the above synthesis is as follows:

[0010]

[0011] The above solvent plays a role in dissolving the raw materials, and can be selected from 1,2-dichloroethane, dichloromethane, toluene, chlorobenzene or trifluorotoluene.

[0012] The molar ratio of the alkenyl allene compound 1, the phenylimine compound 2 and the copper trifluoromethanesulfonate is 1:(1-3):(0.05-0.15).

[0013] The reaction temperature is 25-60°C and the reaction time is 5-10h; the reaction is carried out in air.

[0014] Copper is located in the 29th position of the periodic table, in the fourth period IB group, with an outer electron shell of 3d 10 4s 1 , large in size, low in positive charge, high in polarizability, and loosely holds the outer electrons, making it a soft acid. The carbon in the allene has high polarizability, low electronegativity, and is easily oxidized, making it a soft base. According to the theory of hard and soft acids and bases, soft acids are more likely to combine with soft bases, so when copper activates the allene, the electrons on the allene will flow to the empty orbit of copper, making it easier for the two to combine. In addition, the trifluoromethanesulfonate ion, as a coordinated anion, can form a coordination bond with the copper complex through the oxygen on the trifluoromethanesulfonate ion, increasing stability and thus being more conducive to the reaction.

[0015] The β-alkynyl tetrahydropyridine compound is synthesized by the above-mentioned synthesis method of β-alkynyl tetrahydropyridine compound.

[0016] Furthermore, the structural formula of the above-mentioned β-alkynyl tetrahydropyridine compound is as follows:

[0017]

[0018]

[0019] The above-mentioned β-alkynyltetrahydropyridine compounds are used as intermediates in the chemical field.

[0020] The beneficial effects produced by the present invention are:

[0021] (1) The synthesis process is simple and efficient, and β-alkynyl tetrahydropyridine compounds are directly obtained in a one-step reaction through the tandem reaction of alkenyl allene compounds and phenylimine compounds; (2) The raw materials are cheap and readily available; (3) The reaction conditions are mild and the operation is simple; (4) The substrate has good universality and a wide range of applications. Therefore, the present invention provides an economical, practical and green new method for the synthesis of β-alkynyl tetrahydropyridine compounds. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of compound 3a prepared in Example 1 of the present invention.

[0024] Figure 2 This is the carbon NMR spectrum of compound 3a prepared in Example 1 of the present invention.

[0025] Figure 3 This is the hydrogen nuclear magnetic resonance spectrum of compound 3b prepared in Example 2 of the present invention.

[0026] Figure 4 This is the carbon NMR spectrum of compound 3b prepared in Example 2 of the present invention.

[0027] Figure 5 This is the hydrogen nuclear magnetic resonance spectrum of compound 3c prepared in Example 3 of the present invention.

[0028] Figure 6 This is the carbon NMR spectrum of compound 3c prepared in Example 3 of the present invention.

[0029] Figure 7 This is the hydrogen nuclear magnetic resonance spectrum of compound 3d prepared in Example 4 of the present invention.

[0030] Figure 8 This is the carbon NMR spectrum of compound 3d prepared in Example 4 of the present invention.

[0031] Fig. 9 This is the hydrogen nuclear magnetic resonance spectrum of compound 3e prepared in Example 5 of the present invention.

[0032] Fig.10 This is the carbon NMR spectrum of compound 3e prepared in Example 5 of the present invention.

[0033] Fig.11 This is the hydrogen nuclear magnetic resonance spectrum of compound 3f prepared in Example 6 of the present invention.

[0034] Fig.12 This is the carbon NMR spectrum of compound 3f prepared in Example 6 of the present invention. DETAILED DESCRIPTION

[0035] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] Example 1

[0037] The synthesis method of a β-alkynyl tetrahydropyridine compound of this embodiment, the synthesis equation and synthesis steps are as follows:

[0038]

[0039] Alkenyl allene 1a (0.2mmol, 39.2mg), phenylimine 2 (0.4mmol, 103.6mg), 1,2-dichloroethane (4.0mL), copper trifluoromethanesulfonate (0.02mmol, 7.3mg) were added to a 10mL Shrek tube, and then the reaction system was heated to 40°C and stirred for 8 hours. The reaction was monitored by TLC tracking. After the reaction was completed, the reaction system was cooled to room temperature. Then it was filtered and concentrated in turn. Column chromatography (petroleum ether / ethyl acetate = 10 / 1) gave an oily product 3a (74.7mg, 82%). The characterization data of the compound are as follows: 1 H NMR (400MHz, CDCl3) δ7.73(d,J=6.9Hz,2H),7.51(d,J=7.7Hz,2H),7.37-7.30(m,4H),7.28-7.24(m,6H),5.82( d,J=5.4Hz,1H),2.86-2.77(m,1H),2.71(d,J=17.5Hz,1H),2.40(s,3H),2.15(s,3H),1.59(s,3H),1.26(s,3H); 13C NMR (100MHz, CDCl3) δ142.41,142.12,140.90,137.09,131.10,129.44,128.27,128 .21,128.08,128.01,127.18,126.47,124.18,123.38,94.09,86.65,77.32,77.00,7 6.68,60.97,54.66,33.70,28.73,27.75,22.97,21.42;IR(neat):2922,1728,1648, 1527,1436,1418,1376,1325,1264,1171,1129,1088,948,658; HRMS(ESI)m / z:[M+H] + Calculate for C 29 H 30 NO2S 456.1992, found 456.1994. The H NMR spectrum and C NMR spectrum are as follows Figure 1 and Figure 2 shown.

[0040] Example 2

[0041] The synthesis method of a β-alkynyl tetrahydropyridine compound of this embodiment, the synthesis equation and synthesis steps are as follows:

[0042]

[0043] Alkenyl allene 1b (0.2mmol, 42.8mg), phenylimine 2 (0.4mmol, 103.6mg), 1,2-dichloroethane (4.0mL), copper trifluoromethanesulfonate (0.02mmol, 7.3mg) were added to a 10mL Shrek tube, and then the reaction system was heated to 40°C and stirred for 8 hours. The reaction was followed by TLC. After the reaction was completed, the reaction system was cooled to room temperature. Then, it was filtered and concentrated in turn. Column chromatography (petroleum ether / ethyl acetate = 10 / 1) gave an oily product 3b (71.9mg, 76%). The characterization data of the compound are as follows: 1 H NMR (400MHz, CDCl3) δ7.72(d,J=8.3Hz,2H),7.50(d,J=7.7Hz,2H),7.35-7.29(m,4H),7.26-7.22(m,3H),6.96(t,J=8.7H z,2H),5.81(d,J=4.9Hz,1H),2.84-2.76(m,1H),2.74-2.67(m,1H),2.39(s,3H),2.13(s,3H),1.57(s,3H),1.25(s,3H);13 CNMR (100MHz, CDCl3) δ163.51,161.03,142.43,142.06,140.83,137.24,132.97,132.88,129 .44,128.20,128.04,127.17,126.44,124.00,119.45,119.42,115.65,115.43,92.96,86.29 ,77.32,77.00,76.68,60.88,54.62,33.65,28.71,27.74,22.95,21.40; IR(neat):2924,172 1,1683,1546,1489,1425,1373,1315,1248,1189,1143,1046,957,662; HRMS(ESI)m / z:[M+H] + Calculate for C 29 H 29 FNO2S 474.1898, found 474.1896. The H NMR spectrum and C NMR spectrum are as follows Figure 3 and Figure 4 shown.

[0044] Example 3

[0045] The synthesis method of a β-alkynyl tetrahydropyridine compound of this embodiment, the synthesis equation and synthesis steps are as follows:

[0046]

[0047] Alkenyl allene 1c (0.2mmol, 46.0mg), phenylimine 2 (0.4mmol, 103.6mg), 1,2-dichloroethane (4.0mL), copper trifluoromethanesulfonate (0.02mmol, 7.3mg) were added to a 10mL Shrek tube in sequence, and then the reaction system was heated to 40°C and stirred for 8 hours. The reaction was monitored by TLC tracking. After the reaction was completed, the reaction system was cooled to room temperature. Then, it was filtered and concentrated in sequence. Column chromatography (petroleum ether / ethyl acetate = 10 / 1) gave an oily product 3c (78.5mg, 80%). The characterization data of the compound are as follows: 1H NMR (400MHz, CDCl3) δ7.73(d,J=6.8Hz,2H),7.51(d,J=7.5Hz,2H),7.38-7.30(m,4H),7.27-7.23(m,5H),5.82( d,J=5.3Hz,1H),2.86-2.77(m,1H),2.71(d,J=17.5Hz,1H),2.40(s,3H),2.15(s,3H),1.59(s,3H),1.26(s,3H); 13 C NMR (100MHz, CDCl3) δ142.41,142.12,140.90,137.08,131.10,129.44,128.27,128 .20,128.07,128.00,127.17,126.47,124.18,123.38,94.09,86.65,77.32,77.00,7 6.68,60.96,54.66,33.71,28.73,27.75,22.97,21.40;IR(neat):2924,1726,1618, 1564,1483,1427,1373,1346,1276,1148,1102,1057,967,669; HRMS(ESI)m / z:[M+H] + Calculate for C 29 H 29 ClNO2S 490.1602, found 490.1603. The H NMR spectrum and C NMR spectrum are as follows Figure 5 and Figure 6 shown.

[0048] Example 4

[0049] The synthesis method of a β-alkynyl tetrahydropyridine compound of this embodiment, the synthesis equation and synthesis steps are as follows:

[0050]

[0051] Alkenyl allene 1d (0.2mmol, 52.8mg), phenylimine 2 (0.4mmol, 103.6mg), 1,2-dichloroethane (4.0mL), copper trifluoromethanesulfonate (0.02mmol, 7.3mg) were added to a 10mL Shrek tube in sequence, and then the reaction system was heated to 40°C and stirred for 8 hours. The reaction was followed by TLC. After the reaction was completed, the reaction system was cooled to room temperature. Then, it was filtered and concentrated in sequence. Column chromatography (petroleum ether / ethyl acetate = 10 / 1) gave an oily product 3d (77.6mg, 74%). The characterization data of the compound are as follows: 1H NMR (400MHz, CDCl3) δ7.73(d,J=8.3Hz,2H),7.55-7.48(m,4H),7.44(d,J=8.2Hz,2H),7.32(t,J=7.5Hz,2H),7.27-7.24( m,3H),5.83(d,J=4.3Hz,1H),2.85-2.78(m,1H),2.76-2.68(m,1H),2.40(s,3H),2.16(s,3H),1.58(s,3H),1.26(s,3H); 13 CNMR (100MHz, CDCl3) δ142.51,142.02,140.73,138.76,131.29,129.48,128.25,128. 03,127.26,126.46,125.26,125.22,125.19,125.15,123.84,92.77,89.11,77.32,77. 00,76.68,60.81,54.62,33.78,28.76,27.77,23.05,21.42;IR(neat):2922,1773,164 8,1573,1494,1452,1343,1361,1260,1152,1108,1047,965,672; HRMS(ESI)m / z:[M+H] + Calculate for C 30 H 29 F3NO2S 524.1866, found524.1864. The H NMR spectrum and C NMR spectrum are as follows Figure 7 and Figure 8 shown.

[0052] Example 5

[0053] The synthesis method of a β-alkynyl tetrahydropyridine compound of this embodiment, the synthesis equation and synthesis steps are as follows:

[0054]

[0055] Alkenyl allene 1e (0.2mmol, 42.8mg), phenylimine 2 (0.4mmol, 103.6mg), 1,2-dichloroethane (4.0mL), copper trifluoromethanesulfonate (0.02mmol, 7.3mg) were added to a 10mL Shrek tube, and then the reaction system was heated to 40°C and stirred for 8 hours. The reaction was monitored by TLC tracking. After the reaction was completed, the reaction system was cooled to room temperature. Then it was filtered and concentrated in turn. Column chromatography (petroleum ether / ethyl acetate = 10 / 1) gave an oily product 3e (74.1mg, 78%). The characterization data of the compound are as follows: 1 H NMR (400MHz, CDCl3) δ7.72(d,J=8.3Hz,2H),7.50(d,J=7.6Hz,2H),7.32(t,J=7.5Hz,2H),7.26-7.20(m,4H),7.12(d,J=7.7Hz,1H),7.06-7.0 2(m,1H),7.00-6.95(m,1H),5.82(d,J=4.5Hz,1H),2.85-2.77(m,1H), 2.75-2.68(m,1H),2.40(s,3H),2.14(s,3H),1.57(s,3H),1.25(s,3H); 13 C NMR (100MHz, CDCl3) δ163.54,161.09,142.47,142.05,140.78,138.09,129.88,129.80,129.46, 128.23,128.04,127.22,126.99,126.96,126.45,123.90,117.96,117.74,115.42,115.21,92.8 8,87.57,77.32,77.00,76.68,60.85,54.62,33.73,28.73,27.75,23.00,21.42; IR(neat):2925 ,1743,1672,1518,1476,1432,1375,1346,1288,1164,1131,1047,967,629; HRMS(ESI)m / z:[M+H] + Calculate for C 29 H 29 FNO2S 474.1898, found474.1897. H NMR spectrum and C NMR spectrum are as follows Fig. 9 and Fig.10 shown.

[0056] Example 6

[0057] The synthesis method of a β-alkynyl tetrahydropyridine compound of this embodiment, the synthesis equation and synthesis steps are as follows:

[0058]

[0059] To a 10mL Shrek tube, alkenyl allene 1f (0.2mmol, 42.0mg), phenylimine 2 (0.4mmol, 103.6mg), 1,2-dichloroethane (4.0mL), copper trifluoromethanesulfonate (0.02mmol, 7.3mg) were added in sequence, and then the reaction system was heated to 40°C, stirred for 8 hours, and the reaction was monitored by TLC tracking. After the reaction was completed, the reaction system was cooled to room temperature. Then, it was filtered and concentrated in sequence. Column chromatography (petroleum ether / ethyl acetate = 10 / 1) gave an oily product 3f (76.1mg, 81%). The characterization data of the compound are as follows: 1 H NMR (400MHz, CDCl3) δ7.72(d,J=8.1Hz,2H),7.50(d,J=7.7Hz,2H),7.31(t,J=7.6Hz,2H),7.26-7.23(m,4H),7.18-7.14(m,3H),7.10-7.06 (m,1H),5.81(d,J=5.1Hz,1H),2.84-2.76(m,1H),2.70(d,J=17.3Hz,1H),2.40(s,3H),2.29(s,3H),2.14(s,3H),1.58(s,3H),1.26(s,3H); 13 C NMR (100MHz, CDCl3) δ142.40,142.13,140.92,137.97,136.89,131.65,129.43,128.91, 128.20,128.18,128.08,127.17,126.47,124.24,123.18,94.27,86.29,77.32,77.00,7 6.68,60.99,54.67,33.71,28.74,27.76,22.97,21.41,21.15;IR(neat):2924,1753,16 73,1547,1486,1434,1358,1312,1273,1186,1135,1076,928,637; HRMS(ESI)m / z:[M+H] + Calculate for C 30 H 32 NO2S 470.2148, found 470.2146. The H NMR spectrum and C NMR spectrum are as follows Fig.11 and Fig.12 shown.

[0060] Example 7

[0061] The synthesis method of a β-alkynyl tetrahydropyridine compound of this embodiment, the synthesis equation and synthesis steps are as follows:

[0062]

[0063] Alkenyl allene 1a (0.2mmol, 39.2mg), phenylimine 2 (0.2mmol, 51.8mg), 1,2-dichloroethane (4.0mL), copper trifluoromethanesulfonate (0.03mmol, 10.85mg) were added to a 10mL Shrek tube in sequence, and then the reaction system was stirred at 25°C for 10 hours, and the reaction was monitored by TLC tracking. After the reaction was completed, the reaction system was cooled to room temperature. Then it was filtered and concentrated in sequence. Column chromatography (petroleum ether / ethyl acetate = 10 / 1) gave an oily product 3a (51.2mg, 56%). The characterization data of the compound are as follows: 1 H NMR (400MHz, CDCl3) δ7.73(d,J=6.9Hz,2H),7.51(d,J=7.7Hz,2H),7.37-7.30(m,4H),7.28-7.24(m,6H),5.82( d,J=5.4Hz,1H),2.86-2.77(m,1H),2.71(d,J=17.5Hz,1H),2.40(s,3H),2.15(s,3H),1.59(s,3H),1.26(s,3H); 13 C NMR (100MHz, CDCl3) δ142.41,142.12,140.90,137.09,131.10,129.44,128.27,128 .21,128.08,128.01,127.18,126.47,124.18,123.38,94.09,86.65,77.32,77.00,7 6.68,60.97,54.66,33.70,28.73,27.75,22.97,21.42;IR(neat):2922,1728,1648, 1527,1436,1418,1376,1325,1264,1171,1129,1088,948,658; HRMS(ESI)m / z:[M+H] + Calculate for C 29 H 30 NO2S 456.1992, found 456.1994.

[0064] Example 8

[0065] The synthesis method of a β-alkynyl tetrahydropyridine compound of this embodiment, the synthesis equation and synthesis steps are as follows:

[0066]

[0067] Alkenyl allene 1f (0.2mmol, 42.0mg), phenylimine 2 (0.6mmol, 155.4mg), 1,2-dichloroethane (4.0mL), copper trifluoromethanesulfonate (0.01mmol, 3.6mg) were added to a 10mL Shrek tube, and then the reaction system was heated to 60°C and stirred for 5 hours. The reaction was followed by TLC. After the reaction was completed, the reaction system was cooled to room temperature. Then, it was filtered and concentrated in turn. Column chromatography (petroleum ether / ethyl acetate = 10 / 1) gave an oily product 3f (57.5mg, 61%). The characterization data of the compound are as follows: 1 H NMR (400MHz, CDCl3) δ7.72(d,J=8.1Hz,2H),7.50(d,J=7.7Hz,2H),7.31(t,J=7.6Hz,2H),7.26-7.23(m,4H),7.18-7.14(m,3H),7.10-7.06 (m,1H),5.81(d,J=5.1Hz,1H),2.84-2.76(m,1H),2.70(d,J=17.3Hz,1H),2.40(s,3H),2.29(s,3H),2.14(s,3H),1.58(s,3H),1.26(s,3H); 13 C NMR (100MHz, CDCl3) δ142.40,142.13,140.92,137.97,136.89,131.65,129.43,128.91, 128.20,128.18,128.08,127.17,126.47,124.24,123.18,94.27,86.29,77.32,77.00,7 6.68,60.99,54.67,33.71,28.74,27.76,22.97,21.41,21.15;IR(neat):2924,1753,16 73,1547,1486,1434,1358,1312,1273,1186,1135,1076,928,637; HRMS(ESI)m / z:[M+H] + Calculate for C 30 H 32 NO2S 470.2148, found 470.2146.

[0068] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for synthesizing β-alkynyl tetrahydropyridine compounds, characterized in that: The steps are as follows: dissolving an alkenyl allene compound 1 and a phenylimine compound 2 in a solvent, adding copper trifluoromethanesulfonate, and reacting to obtain a β-alkynyl tetrahydropyridine compound; Among them, the structural formula of alkenyl allene compound 1 is The structural formula of phenylimine compound 2 is There are electron-withdrawing groups and electron-donating groups on R.

2. The method for synthesizing β-alkynyl tetrahydropyridine compounds according to claim 1, characterized in that: The R is a phenyl group or a substituted phenyl group, and the substituent on the benzene ring of the substituted phenyl group is fluorine, chlorine, trifluoromethyl or methyl.

3. The method for synthesizing β-alkynyl tetrahydropyridine compounds according to claim 2, characterized in that: The substituent is at the para or meta position of the benzene ring.

4. The method for synthesizing β-alkynyl tetrahydropyridine compounds according to claim 1, characterized in that: The reaction equation of the synthesis is as follows:

5. The method for synthesizing the β-alkynyl tetrahydropyridine compound according to any one of claims 1 to 4, characterized in that: The solvent is 1,2-dichloroethane, dichloromethane, toluene, chlorobenzene or trifluorotoluene.

6. The method for synthesizing β-alkynyl tetrahydropyridine compounds according to claim 5, characterized in that: The molar ratio of the alkenyl allene compound 1, the phenylimine compound 2 and copper trifluoromethanesulfonate is 1:(1-3):(0.05-0.15).

7. The method for synthesizing β-alkynyltetrahydropyridine compounds according to claim 6, characterized in that: The reaction temperature is 25-60°C and the reaction time is 5-10h.

8. β-Alkynyltetrahydropyridine compounds synthesized by the method for synthesizing β-alkynyltetrahydropyridine compounds according to claim 1.

9. The β-alkynyl tetrahydropyridine compound according to claim 8, characterized in that: The structural formula of the β-alkynyl tetrahydropyridine compound is as follows:

10. Use of the β-alkynyltetrahydropyridine compound according to claim 8 as an intermediate in the chemical field.

Images