Preparation method and application of 6, 6 '-disubstituted 2, 2'-dipyridyl ligand and iron complex of 6, 6 '-disubstituted 2, 2'-dipyridyl ligand

Abstract

The invention belongs to the technical field of catalyst preparation, and particularly relates to a preparation method and application of a 6, 6 '-disubstituted 2, 2'-dipyridyl ligand and an iron complex of the 6, 6 '-disubstituted 2, 2'-dipyridyl ligand, and the preparation method comprises the following steps: carrying out catalytic coupling on 6, 6 '-dibromo-2, 2'-dipyridyl and arylboronic acid to prepare 6, 6 '-di-(2, 4, 6-trimethylphenyl)-2, 2'-dipyridyl; the 2, 2 '-bipyridyl iron complex is complexed with ferrous chloride to obtain the corresponding 2, 2'-bipyridyl iron complex. The catalyst can catalyze the transfer hydroalumination reaction of various internal alkyne and has good tolerance to functional groups, and substituent groups such as halogen, alkoxy, 2-naphthyl, ferrocenyl and the like do not influence the reaction result; the regioselectivity and the stereoselectivity are high; the cis-beta-addition regioselectivity different from that of a known transfer hydroalumination reaction system is given for the transfer hydroalumination reaction of aryl alkyl internal alkyne and alkenyl alkyl internal alkyne.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalyst preparation, and particularly relates to a preparation method and application of a 6,6'-disubstituted 2,2'-bipyridine ligand and its iron complex. Background Art

[0002] Organoaluminum compounds are based on the most abundant metal element in the earth's crust and have high stability. They can undergo various transformations and are important organometallic reagents, which are widely used in organic synthesis and materials chemistry. Organoaluminum compounds are one of the earliest synthesized organometallic compounds. Due to the electron-deficient nature of the metal aluminum center, trivalent organoaluminum compounds are a class of Lewis acids and belong to hard acids. They will form aluminum-centered tetrahedral adducts with neutral Lewis bases such as pyridine, tetrahydrofuran, and tertiary amines. The carbon-aluminum bond is a polar bond and is prone to undergo various types of reactions with different types of electrophilic reagents, such as titanium salt-promoted addition reactions, palladium-catalyzed coupling reactions, copper salt-promoted substitution reactions, etc., which lays the foundation for their application in organic synthetic chemistry.

[0003] The transfer hydroalumination reaction of alkynes is an effective method for synthesizing organoaluminum compounds. By the selective addition of commercially available simple organoaluminum reagents to alkynes, novel vinylaluminum compounds with high application value can be synthesized. However, there are still many important problems to be solved in the transfer hydroalumination reaction of alkynes. In the existing reaction systems, whether it is the direct hydroalumination of alkynes by aluminum hydride reagents or the transfer hydroalumination reaction of alkynes by alkylaluminum reagents, it is impossible to achieve the cis-β-addition reaction of simple unsymmetrical internal alkynes to obtain trisubstituted vinylaluminum compounds with high regioselectivity. This is because the types of catalysts for this type of reaction are few, which limits the expansion and application of this type of reaction. Therefore, the development of novel iron catalysts for the transfer hydroalumination reaction of alkynes to overcome the limitations of existing catalysts is one of the research focuses in this field. Summary of the Invention

[0004] The purpose of the present invention is to provide a preparation method and application of a 6,6'-disubstituted 2,2'-bipyridine ligand and its iron complex. Finally, the prepared 2,2'-bipyridine iron complex C1 can catalyze the transfer hydroalumination reaction of various internal alkynes and trialkylaluminum in the presence of additives, showing high activity and excellent selectivity, and having good application prospects.

[0005] The purpose of the present invention is achieved by the following technical solutions:

[0006] The present invention provides a 6,6'-disubstituted 2,2'-bipyridine ligand, and the structural formula of the 6,6'-disubstituted 2,2'-bipyridine ligand is

[0007] The present invention also provides a 6,6'-bis(2,4,6-trimethylphenyl)-2,2'-bipyridine-FeCl2 complex, which is prepared by a complexation reaction of the 6,6'-disubstituted 2,2'-bipyridine ligand with an iron salt.

[0008] The present invention also provides a preparation method of the 6,6'-disubstituted 2,2'-bipyridine ligand, comprising the following steps: adding a catalyst and a base in a solvent, and performing a Suzuki coupling reaction on 6,6'-dibromo-2,2'-bipyridine and an arylboronic acid to obtain the product.

[0009] Further, the solvent is a mixed solvent of toluene and water, the catalyst is Pd(dppf)Cl2, and the base is Ba(OH)2·8H2O.

[0010] Further, the temperature of the coupling reaction is 90-120°C, and the time of the coupling reaction is 10-48 h.

[0011] The present invention also provides a preparation method of the 6,6'-bis(2,4,6-trimethylphenyl)-2,2'-bipyridine-FeCl2 complex, comprising the following steps: performing a complexation reaction on the 6,6'-disubstituted 2,2'-bipyridine ligand and a corresponding iron salt in an organic solvent for 1-72 hours to obtain the product.

[0012] Further, the organic solvent includes one or more of toluene, benzene, xylene, tetrahydrofuran, ether, and 1,4-dioxane, and the temperature of the complexation reaction is 0-140°C.

[0013] The present invention also provides an application of the 6,6'-bis(2,4,6-trimethylphenyl)-2,2'-bipyridine-FeCl2 complex in the transfer hydroalumination reaction of an alkyne and triethylaluminum, and the 6,6'-bis(2,4,6-trimethylphenyl)-2,2'-bipyridine-FeCl2 complex is used as a catalyst in the transfer hydroalumination reaction.

[0014] Further, the application includes adding the catalyst into a reaction flask, and then successively adding an alkyne substrate, a solvent, and triethylaluminum, and stirring and reacting at a specified temperature until the reaction is completed.

[0015] Further, the solvent is any one or more of toluene, benzene, xylene, n-hexane, tetrahydrofuran, ether, and 1,4-dioxane; the dosage of the catalyst is 2.5-5 mol%; the concentration of the alkyne substrate is 0.02 M; the reaction temperature is 0-100°C; and the reaction time is 12-72 hours.

[0016] The beneficial effects of the present invention are as follows:

[0017] In the present invention, 6,6'-dibromo-2,2'-bipyridine is catalytically coupled with arylboronic acid to prepare 6,6'-bis(2,4,6-trimethylphenyl)-2,2'-bipyridine L1; 6,6'-substituted 2,2'-bipyridine L1 is complexed with ferrous chloride salt to obtain the corresponding dichloro(6,6'-bis(2,4,6-trimethylphenyl)-2,2'-bipyridine)iron(II) C1. This novel 2,2'-bipyridine iron complex C1 can catalyze the transfer hydroalumination of a variety of internal alkynes and exhibits the following characteristics: it has good tolerance to functional groups, and substituents such as halogen, alkoxy, 2-naphthyl, ferrocenyl, etc. do not affect the reaction results; it has high regioselectivity and stereoselectivity; for the transfer hydroalumination of arylalkyl internal alkynes and alkenylalkyl internal alkynes, it gives a cis-β-addition regioselectivity different from that of the known transfer hydroalumination reaction systems. The above characteristics indicate that the novel 2,2'-bipyridine iron complex catalyst provided by the present invention overcomes the disadvantages of the prior art and has good application prospects. Brief Description of the Drawings

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0019] Figure 1 It is the crystal structure diagram of C1 prepared in Example 2 of the present invention;

[0020] Figure 2 It is the specific structure diagram of C1-C13 involved in Example 3 of the present invention. Detailed Embodiments

[0021] The following will describe in detail the embodiments of the present invention. The embodiments are intended to explain the present invention and should not be construed as limiting the present invention. For those not specified in the embodiments in terms of specific techniques or conditions, they shall be carried out according to the techniques or conditions described in the literature in the art or according to the product specifications. For reagents or instruments not specified in terms of the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0022] In addition, the following abbreviations are used in the embodiments, and their meanings are as follows:

[0023] Me is methyl, Et is ethyl, i Pr is isopropyl, tBu is tert-butyl, Ph is phenyl, THF is tetrahydrofuran, DCM is dichloromethane, PE is petroleum ether, and EA is ethyl acetate;

[0024] TLC is thin layer chromatography, NMR is nuclear magnetic resonance, HRMS is high resolution mass spectrometry, IR is infrared absorption spectroscopy, and XRD is X-ray crystal diffraction.

[0025] The solvents used were purified and dried by standard operations before use; all the reagents used were commercially available or synthesized according to the methods in the existing literature, and were purified before use.

[0026] The preparation steps of 6,6'-bis(2,4,6-trimethylphenyl)-2,2'-bipyridine (L1) in the present invention are as follows:

[0027] In a mixed solvent of toluene and water, at 90-120 °C, using Pd(dppf)Cl2 as the catalyst and Ba(OH)2·8H2O as the base, 6,6'-dibromo-2,2'-bipyridine and arylboronic acid were subjected to Suzuki coupling reaction for 10-48 hours to prepare 6,6'-di-(2,4,6-trimethylphenyl)-2,2'-bipyridine L1. The reaction formula is:

[0028]

[0029] The preparation steps of ferrous chloride complex of 6,6'-di-(2,4,6-trimethylphenyl)-2,2'-bipyridine (C1) in the present invention are as follows:

[0030] In one or several organic solvents such as toluene, benzene, xylene, tetrahydrofuran, ether, and 1,4-dioxane, at 0-140 °C, 6,6'-disubstituted 2,2'-bipyridine L1 was complexed with the corresponding iron salt for 1-72 hours to prepare 6,6'-disubstituted 2,2'-bipyridine iron complex C1. The reaction formula is:

[0031]

[0032] The steps of using ferrous chloride complex of 6,6'-di-(2,4,6-trimethylphenyl)-2,2'-bipyridine (C1) as a catalyst in the transfer hydroalumination reaction of alkynes and triethylaluminum are as follows:

[0033] The catalyst was added to the reaction flask, and then the alkyne substrate, solvent, and triethylaluminum were added in sequence, and the reaction was stirred at the specified temperature until the end. The reaction formula is:

[0034]

[0035] Among them: C1 is 2,2'-bipyridine iron complex; R 1 ~R2 is a C1-C8 alkyl group, haloalkyl group, benzyl group, phenethyl group, styryl group, substituted styryl group, phenyl group, substituted phenyl group, naphthyl group, substituted naphthyl group, R 1 ~R 2 may be the same or different.

[0036] In the above transfer hydroalumination reaction process, the solvent used is one or more organic solvents among toluene, benzene, xylene, n-hexane, tetrahydrofuran, ether, 1,4-dioxane; the catalyst dosage is 2.5-5 mol%; the substrate concentration is 0.02 M; the reaction temperature is 0-100 °C; the reaction is carried out for 12-72 hours.

[0037] For a clearer understanding of the technical features, objectives, and effects of the present invention, the specific embodiments of the present invention will now be described.

[0038] Example 1 Preparation of 6,6'-bis(2,4,6-trimethylphenyl)-2,2'-bipyridine

[0039] In this example, the preparation steps of 6,6'-bis(2,4,6-trimethylphenyl)-2,2'-bipyridine (L1) are as follows:

[0040] Add 6,6'-dibromo-2,2'-bipyridine (464 mg, 1.5 mmol), Pd(dppf)Cl2 (55 mg, 0.076 mmol, 5 mol%), Ba(OH)2·8H2O (2.37 g, 7.5 mmol, 5 equiv), toluene (20 mL) and water (2 mL) into a 100 mL three-necked round-bottom flask. Install a reflux condenser and a gas extraction head. After the reaction system is frozen and degassed three times, install an argon balloon. Heat the reaction system to reflux and stir until the raw materials are completely converted, then cool to room temperature. Filter the reaction system by suction, wash the organic phase with water, extract it with dichloromethane (30 mL×3), dry the organic phase with anhydrous MgSO4, filter by suction, evaporate the solvent by rotary evaporation, and obtain the product L1 through silica gel column chromatography (PE / EA = 20:1). The specific reaction formula is:

[0041]

[0042] The product L1 is a white solid, TLC R f = 0.65 (PE / EA = 20:1), 540 mg, separation yield 92%, melting point: 220-221 °C.

[0043] 1 HNMR(400MHz,CDCl3)δ8.38(dd,J = 7.9,1.0Hz,2H,Ar-H),7.80(t,J = 7.8Hz,2H,Ar-H),

[0044] 7.21 (dd, J = 7.6, 1.0 Hz, 2H, Ar-H), 6.98 (s, 4H, Ar-H), 2.35 (s, 6H, 2CH3), 2.12 (s, 12H,

[0045] 4CH3).

[0046] 13 CNMR (101 MHz, CDCl3) δ 159.0 (2C, Ar-C), 156.2 (2C, Ar-C), 138.0 (2C, Ar-C), 137.4 (2C, Ar-C), 136.9 (4C, Ar-C), 135.9 (2C, Ar-C), 128.4 (4C, Ar-C), 124.7 (2C, Ar-C), 119.2

[0047] (2C, Ar-C), 21.1 (2CH3), 20.4 (4CH3).

[0048] HRMS(ESI) calcd for [M+H, C 28 H 29 N2] + : 392.2325; found 392.2328.

[0049] In summary, 6,6'-bis(2,4,6-trimethylphenyl)-2,2'-bipyridine (L1) was successfully synthesized in this example with a yield of 92%. Through the Suzuki coupling reaction, using Pd(dppf)Cl2 as the catalyst, highly efficient and highly selective synthesis was achieved. The purity of the product L1 was ensured by silica gel column chromatography, providing a high-quality ligand for the preparation of subsequent iron complexes.

[0050] Example 2 Synthesis of 6,6'-bis(2,4,6-trimethylphenyl)-2,2'-bipyridine-FeCl2 complex (C1)

[0051] The preparation steps of 6,6'-bis(2,4,6-trimethylphenyl)-2,2'-bipyridine-FeCl2 complex in this example are as follows:

[0052] In a glove box filled with argon, add L1 (1 mmol), FeCl2 (1 mmol), anhydrous tetrahydrofuran (5 mL), and anhydrous toluene (10 mL) to a 50 mL round-bottom flask with a side arm. Stir the reaction system under reflux for 24 hours, and an orange-yellow solid insoluble substance is formed in the system. After the reaction system is cooled to room temperature, perform anhydrous and anaerobic filtration in the glove box, and wash the filter cake with anhydrous n-hexane (10 mL × 3). After vacuum desolvation, the target product C1 is obtained. This product is an orange-yellow solid, 500 mg, with a separation yield of 96%, melting point: 257 - 259 °C. Evaporate and crystallize at room temperature in dichloromethane to obtain the single crystal structure of this complex. The specific reaction formula is:

[0053]

[0054] , and the final crystal structure of C1 is as shown in Figure 1 shown.

[0055] 1 1H NMR (400 MHz, CDCl3) δ 3.76, 2.36, 1.86, 1.65, 1.31, 1.00, 0.85, -13.2, -17.79.

[0056] IR (neat) 3436 w, 3069 w, 2962 w, 2918 w, 2855 m, 1613 m, 1593 s, 1563 s, 1465 s, 1376 w, 1230 w,

[0057] 1180 m, 1066 w, 1033 w, 1016 w, 1005 m, 854 m, 809 s, 761 w, 687 w, 645 w cm -1 .

[0058] Anal. calcd. for C 28 H 28 N2Cl2Fe: C, 64.76; H, 5.44; N, 5.39. found: C, 65.18; H, 4.76; N, 6.50. Magnetic Susceptibility (Evans, CDCl3, 298.15 K): μ eff = 5.44 μ B .

[0059] Table 1 Crystal structure and single crystal test parameters of C1

[0060]

[0061]

[0062] From the above Table 1 and Figure 1It can be seen that in this example, the 6,6'-bis(2,4,6-trimethylphenyl)-2,2'-bipyridine-FeCl2 complex (C1) was successfully synthesized with a yield of 96%. Through the complexation reaction of iron salt and ligand L1, an iron complex with high catalytic activity was prepared, and the single crystal structure of C1 was also obtained, further verifying its chemical structure.

[0063] Example 3 Catalyst Evaluation for Transfer Hydroalumination of 4-Phenylphenylacetylene

[0064] This example aims to clarify the evaluation of different catalysts in the transfer hydroalumination of 4-phenylphenylacetylene. The standard experimental procedure is as follows:

[0065] In a glove box filled with argon, a catalyst (Cat., 0.01 mmol, 5 mol%) was added to a 10 mL sealed tube, followed by internal alkyne (0.2 mmol) and anhydrous toluene (1 mL). The reaction mixture was stirred at room temperature for 1 minute, and then AlEt3 (1 M toluene solution, 240 μL, 0.24 mmol, 1.2 equiv) was added. After stirring at room temperature for 72 hours, the reaction was quenched with 100 μL of heavy water. After stirring at room temperature for 10 minutes, the reaction system was made into a dry sample with silica gel powder, separated and purified by short silica gel column chromatography, and the filtrate was concentrated by rotary evaporation to obtain the target product. The evaluation of different catalysts used in the transfer hydroalumination reaction of internal alkyne is shown in Table 2, and the specific structures of the catalysts used are as Figure 2 shown. The specific reaction equation is:

[0066]

[0067] Table 2 Catalyst Evaluation for Transfer Hydroalumination Reaction of Internal Alkyne

[0068]

[0069]

[0070] As can be seen from Table 2 above, in this example, by comparing the performance of different catalysts (including C1, Cp2TiCl2, Ni(PPh3)2Cl2, etc.) in the transfer hydroalumination reaction of 4-phenylphenylacetylene, it was proved that the iron complex C1 provided by the present invention showed better activity and selectivity than other control catalysts in the transfer hydroalumination reaction of internal alkyne and trialkylaluminum.

[0071] Example 4 2,2'-Bipyridine Iron Catalyst for Transfer Hydroalumination of 4-Phenylphenylacetylene

[0072] In this example, a 2,2'-bipyridine iron catalyst was used for the transfer hydroalumination of 4-phenylphenylacetylene. The specific steps are as follows:

[0073] In a glove box filled with argon, C1 (0.01 mmol, 5 mol%) and internal alkyne (0.2 mmol) and anhydrous toluene (1 mL) were added to a 10 mL sealed tube. The reaction mixture was stirred at room temperature for 1 minute, and then AlEt3 (1 M toluene solution, 240 μL, 0.24 mmol, 1.2 equiv) was added. After stirring at room temperature for 72 hours, the reaction was quenched with 100 μL of heavy water. After stirring at room temperature for 10 minutes, the reaction system was made into a dry sample with silica gel powder, separated and purified by short silica gel column chromatography, and the filtrate was concentrated by rotary evaporation. The characterization data of the internal alkene product are as follows:

[0074] 1-[(1Z)-2-deuteroprop-1-enyl]-4-phenylbenzene (2a)

[0075]

[0076] Using C1 as the catalyst and D2O to quench the reaction. Colorless liquid, TLC R f = 0.35 (PE), 35 mg, isolated yield 90%, r.r. = 92:8.

[0077] 1 1H NMR (400 MHz, CDCl3) δ 7.65 - 7.54 (m, 4H, Ar-H), 7.46 - 7.28 (m, 5H, Ar-H), 6.46 (s, 1H,

[0078] =CH), 1.94 (s, 3H, CH3).

[0079] 13 13C NMR (101 MHz, CDCl3) δ 140.8 (1C, Ar-C), 139.1 (1C, Ar-C), 136.6 (1C, Ar-C), 129.3 (1C,

[0080] =CH), 129.2 (2C, Ar-C), 128.7 (2C, Ar-C), 127.2 (1C, Ar-C), 127.0 (2C, Ar-C), 126.8 (2C,

[0081] Ar-C), 126.7 (1C, t, J = 23.2 Hz, =CD), 14.6 (1C, CH3).

[0082] HRMS(EI) calcd for [M,C 15 H 13 D] + : 195.1153; found 195.1150.

[0083] In summary, this example further verifies the high efficiency and selectivity of C1 in catalyzing the transfer hydroalumination of 4-phenylphenylpropyne. The target product 2a with high purity was obtained, with a yield of 90% and a regioselectivity (r.r.) of 92:8, demonstrating the application potential and value of the C1 catalyst in practical organic synthesis.

[0084] Example 5 Transfer Hydroalumination of Internal Alkynes Catalyzed by the Iron Complex C1 of 2,2'-Bipyridine Iron Catalyst

[0085] The purpose of this example is to clarify the catalytic situations of different internal alkynes in the transfer hydroalumination process catalyzed by the iron complex C1 of 2,2'-bipyridine iron catalyst. The standard experimental procedures are as follows:

[0086] In a glove box filled with argon, add C1 (0.01 mmol, 5 mol%), internal alkyne (0.2 mmol) and anhydrous toluene (1 mL) to a 10 mL sealed tube. Stir the reaction mixture at room temperature for 1 minute, and then add AlEt3 (1 M toluene solution, 240 μL, 0.24 mmol, 1.2 equiv). After stirring at room temperature for 72 hours, transfer the reaction tube to a cryogenic refrigerator in the glove box to cool, and quench the reaction with a solution of iodine (153 mg, 0.6 mmol, 3 equiv) in tetrahydrofuran. After stirring at room temperature for 1 hour, quench the excess iodine with a saturated aqueous Na2S2O3 solution, and extract with diethyl ether (30 mL × 3). After combining the organic phases, dry over anhydrous MgSO4. Filter through diatomaceous earth, remove the solvent by rotary evaporation, and separate and purify by short silica gel column chromatography. Concentrate the filtrate by rotary evaporation to obtain the target product. It should be noted that deuterated olefins are obtained by purifying the quenched reaction system with heavy water. The experimental results of the transfer hydroalumination of internal alkynes catalyzed by the 2,2'-bipyridine iron complex C1 are shown in Table 3.

[0087] Table 3 Experimental Results of the Transfer Hydroalumination of Internal Alkynes Catalyzed by the 2,2'-Bipyridine Iron Complex C1

[0088]

[0089]

[0090] In summary, the present invention provides a preparation method of a novel 6,6'-disubstituted 2,2'-bipyridine ligand and its iron complex, and successfully synthesizes the iron complex C1 with high catalytic activity.

[0091] The C1 catalyst exhibits excellent activity and selectivity in catalyzing the transfer hydroalumination reaction of various internal alkynes with trialkylaluminum. Especially for substrates such as 4-phenylphenylpropyne, it can efficiently generate target products with high regioselectivity.

[0092] The present invention provides an efficient and selective new method for synthesizing trisubstituted alkenylaluminum compounds, which has important application value and application prospects.

[0093] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered by the scope of the claims of the present invention.

Claims

1. A 6,6'-disubstituted 2,2'-bipyridine ligand, characterized in that, The structural formula of the 6,6'-disubstituted 2,2'-bipyridine ligand is 2. A 6,6'-bis(2,4,6-trimethylphenyl)-2,2'-bipyridine-FeCl2 complex, characterized in that, The 6,6'-bis(2,4,6-trimethylphenyl)-2,2'-bipyridine-FeCl2 complex is prepared by complexing the 6,6'-disubstituted 2,2'-bipyridine ligand described in Claim 1 with a ferrous chloride salt.

3. The preparation method of the 6,6'-disubstituted 2,2'-bipyridine ligand as claimed in claim 1, characterized in that, It includes the following steps: adding a catalyst and a base in a solvent, and performing a Suzuki coupling reaction between 6,6'-dibromo-2,2'-bipyridine and an arylboronic acid to obtain the product.

4. The preparation method according to claim 3, characterized in that, The solvent is a mixed solvent of toluene and water, the catalyst is Pd(dppf)Cl2, and the base is Ba(OH)2·8H2O.

5. The preparation method according to claim 3, characterized in that, The temperature of the coupling reaction is 90-120°C, and the time of the coupling reaction is 10-48 h.

6. The preparation method of the 6,6'-bis(2,4,6-trimethylphenyl)-2,2'-bipyridine-FeCl2 complex according to claim 2, characterized in that, It includes the following steps: complexing the 6,6'-disubstituted 2,2'-bipyridine ligand described in Claim 1 with a ferrous chloride salt in an organic solvent for 1-72 hours to obtain the product.

7. The preparation method according to claim 6, characterized in that, The organic solvent includes one or more of toluene, benzene, xylene, tetrahydrofuran, ether, and 1,4-dioxane, and the temperature of the complexing reaction is 0-140°C.

8. Use of the 6,6'-bis(2,4,6-trimethylphenyl)-2,2'-bipyridine-FeCl2 complex according to claim 2 in the transfer hydroalumination reaction of alkynes and triethylaluminum, characterized in that, The 6,6'-bis(2,4,6-trimethylphenyl)-2,2'-bipyridine-FeCl2 complex is used as the catalyst in the transfer hydroalumination reaction.

9. The application according to claim 8, characterized in that, The application includes adding the catalyst into a reaction flask, and then successively adding an alkyne substrate, a solvent, and triethylaluminum, and stirring and reacting at a specified temperature until the reaction ends.

10. The application according to claim 9, characterized in that, The solvent is any one or more of toluene, benzene, xylene, n-hexane, tetrahydrofuran, ether, and 1,4-dioxane; the dosage of the catalyst is 2.5-5 mol%; the concentration of the alkyne substrate is 0.02 M; the reaction temperature is 0-100°C; the reaction time is 12-72 hours.

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