Preparation of a new organoaluminum hydride and process for the catalytic preparation of unsaturated alcohol compounds

Abstract

The application discloses a preparation method of a novel aluminum hydrogen compound and a preparation method of unsaturated alcohol compounds catalyzed by the aluminum hydrogen compound. The preparation method is as follows: first, 1-phenyl-1,3-butanedione and 2,6-diisopropylaniline are condensed to form a ligand, then the ligand is reacted with 0.5 equivalent of trihydroaluminum trimethylamine to form the novel aluminum hydrogen compound. Subsequently, the aluminum hydrogen compound is used as a catalyst to catalyze the reaction of unsaturated ketone compounds and boron hydride compounds and hydrolysis to obtain corresponding unsaturated alcohol compounds. The preparation method is simple, the synthesized aluminum hydrogen compound has a remarkable effect in the boron hydride reaction of unsaturated ketones, the catalyst is only applicable to 5%, the reaction speed is fast and the yield is high, the problems of high price of the catalyst used in the preparation method of the unsaturated alcohol compounds and the need of high-pressure hydrogen are solved, and the concept of green chemistry is met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of catalytic reaction of metal aluminum hydride, and particularly relates to a preparation method of a novel organic aluminum hydride and application thereof in catalyzing borohydride reaction of unsaturated ketone. BACKGROUND

[0002] Unsaturated alcohols are a class of organic compounds containing double bonds and hydroxyl functional groups, which play an important role in chemical reactions. They can be used as starting materials or intermediates in various reactions such as addition, oxidation, reduction, etc., and can also be used to construct complex organic molecules. They have nucleophilic properties and are commonly found in biologically active molecules, so they have wide applications in the fields of organic synthesis, medicinal chemistry and biochemistry.

[0003] Traditional preparation methods such as Luche reduction reaction selectively reduce the carbonyl group in α, β-unsaturated ketones or aldehydes to generate allyl alcohol. In this method, reagents such as sodium borohydride (NaBH4) and cerium chloride are usually used to achieve this selective reduction while maintaining the integrity of other functional groups in the molecule. In addition, transition metal-catalyzed high-pressure hydrogenation has also been applied. However, the reduction method of unsaturated bonds generally uses catalytic hydrogenation, but it is usually accompanied by high pressure, flammable hydrogen, high reaction temperature, etc. In this context, borane is often used as an alternative reducing agent to avoid the use of flammable hydrogen for high-pressure hydrogenation reaction. Pinacol borane (HBpin) has the advantages of air stability, low cost, good functional group tolerance, etc. Therefore, catalytic borohydride hydrolysis of unsaturated ketone compounds to obtain unsaturated alcohols is a novel and meaningful method for corresponding hydrogenation.

[0004] The literature reported selective borohydride reduction method of unsaturated ketone has used ammonia borane as reagent, which has strong reducing property and is easy to decompose to release explosive hydrogen, which has great danger in operation, and the solvent used is difficult to handle after the reaction is completed, which is very harmful to the environment (K. Jian, B. Li, S. Zhu, Q. Xuan and Q. Song, Org. Chem. Front., 2022, 9, 1109-1114.). Zhu group also used transition metal nickel (F. Chen, Y. Zhang, L. Yu and S. Zhu, Angew. Chem., Int. Ed., 2017, 56, 1-5; ) and Teskey group used cobalt metal as catalyst (F. Beltran, E. Bergamaschi, I. Funes-Ardoiz and C. J. Teskey Angew. Chem., Int. Ed., 2020, 59, 21176-21182.). However, the disadvantages of these methods are that the reduction selectivity of different functional groups is not good, and toxic transition metal organic compounds are used, which is not conducive to the industrial application of the method.

[0005] Using an easy-to-prepare non-toxic catalyst, reducing the amount of catalyst and solvent, reducing the reaction temperature, and shortening the reaction time are the urgent problems to be solved in the preparation method of unsaturated alcohol compounds. SUMMARY

[0006] The purpose of the present application is to provide a cheap and effective method for preparing unsaturated alcohol by catalyzing the borohydride reaction of unsaturated ketone with aluminum hydride.

[0007] The technical solution of the present application is as follows:

[0008] An aluminum hydride: the specific structure is as follows

[0009]

[0010] A preparation method of the aluminum hydride, comprising the following steps:

[0011] (1) Under the protection of nitrogen, 1-phenyl-1,3-butanedione and 2,6-diisopropylaniline are mixed with hydrochloric acid in a molar ratio of 1:1:0.001 in an ethanol solvent at 80°C reflux for 36h, after the reaction is completed, the crystal is precipitated after the concentrated method is placed in the refrigerator overnight, the crystal is filtered and washed with ice methanol, and then the solvent is removed to obtain pure ligand.

[0012] (2) In the absence of water and oxygen, under nitrogen protection, in a Schlenk reaction flask, slowly drop di-trihydroaluminum trimethylamine into the above ligand toluene solution at low temperature, the molar ratio of the two is 2:1, stir overnight at room temperature, stand and filter, then concentrate the toluene, and put it into a low-temperature refrigerator the next day to obtain a large amount of crystals, which are new aluminum hydride compounds.

[0013] The reaction formula of the above method is as follows:

[0014]

[0015] Application of the aluminum hydride compound in the borohydride reaction of unsaturated ketones.

[0016] Application of the aluminum hydride compound in catalyzing the borohydride reaction of unsaturated ketones and borane, comprising the following steps:

[0017] In the absence of water and oxygen, under nitrogen protection, in a glove box, the aluminum hydride compound is added to a Schlenk flask of about 10 ml, then the corresponding proportion of borane is added and mixed uniformly, and finally the unsaturated ketone is added, followed by heating at 80℃ for 12h, then the reaction is terminated by exposure to air, then 1mL of methanol is added to the system and stirred for half an hour, then the solvent is removed, and the crude product is purified by column chromatography using petroleum ether / ethyl acetate as the elution system to obtain the unsaturated alcohol compound.

[0018] In the above technical solution, the unsaturated ketone is selected from one of aromatic unsaturated ketones and aliphatic unsaturated ketones;

[0019] The aromatic unsaturated ketone is benzalacetone, 4-chlorobenzalacetone, 3.5-dichlorobenzalacetone, chalcone, 4-chlorochalcone, 4-fluorochalcone, 4-methoxychalcone, 4'-fluorochalcone, 4'-chlorochalcone, 4-phenyl-3-butyn-2-one

[0020] The aliphatic unsaturated ketone is cyclohexenone, cyclopentenone, 3-methylcyclopentenone, verbenone, levorotatory carvone, testosterone.

[0021] The borane is pinacol borane.

[0022] The amount of the catalyst is 5% of the molar number of the ketone, the molar ratio of the borane to the ketone is 1:1, the reaction temperature is 80℃, and the reaction time is 12h.

[0023] The above reaction formula is as follows:

[0024]

[0025] Among them, R1 and R2 come from the selected ketone.

[0026] Advantages: compared with the prior art, the present application has the following advantages

[0027] 1) The present application first catalyzes the reaction of unsaturated ketone and pinacol borane to synthesize unsaturated alcohol by using organic aluminum hydride compound, wherein the aluminum hydride compound has extremely high catalytic activity, simple structure and is easy to synthesize, not only provides a new scheme for preparing unsaturated alcohol, but also expands the application of aluminum hydride compound.

[0028] 2) The aluminum hydride compound of the present application can catalyze the borohydride reaction of unsaturated ketone and borane under mild conditions with high activity, and the catalyst dosage is only 5% of the molar amount of the substrate. Compared with several catalysts reported in the literature, the reaction speed is very fast, and almost 100% conversion rate can be achieved. The reaction condition is mild, the reaction is simple and controllable, and is highly consistent with the concept of green chemistry. DETAILED DESCRIPTION

[0029] The technical solutions in the present application will be described below in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0030] Example 1

[0031] Preparation of aluminum hydride compound

[0032] Under the protection of nitrogen, 100 mL of anhydrous methanol was added to a 250 mL round-bottom flask, then 40 mmol of 1-phenyl-1,3-butanedione and 2,6-diisopropylaniline and hydrochloric acid 0.04 mmol were added, and refluxed at 80℃ for 36h. After the reaction was completed, the solvent was concentrated to 30 mL and placed in a refrigerator overnight. The next day, a large amount of colorless crystals were precipitated, which were filtered and washed with ice ethanol, and then the solvent was removed to obtain the ligand. Under anhydrous and anaerobic conditions, in a Schlenk reaction bottle under the protection of nitrogen, 10 mmol of trihydroaluminum trimethylamine was slowly added dropwise to a toluene solution of 10 mmol of the ligand at low temperature, and stirred at room temperature overnight. After standing and filtering, the toluene was concentrated and placed in a low-temperature refrigerator the next day to obtain a large amount of crystals, which were the new aluminum hydride compound. The yield was 73%.

[0033] 1H NMR (400 MHz, Chloroform-d) δ 7.18 (s, 2H, Ar-H), 7.15 (s, 1H, Ar-H), 7.04 (dd, J = 8.5, 7.1 Hz, 2H, Ar-H), 7.00 - 6.96 (m, 1`H, Ar-H), 6.94 - 6.86 (m, 2H, Ar-H), 5.92 (s, 1H, γ-CH), 3.15 (p, J = 6.9 Hz, 1H, CHMe2), 3.01 (p, J = 6.8 Hz, 1H, CHMe2), 1.66 (s, 3H, CH3), 1.14 - 0.93 (m, 12H, CHMe2).

[0034] 13 C NMR (101 MHz, CDC13) δ 187.40, 175.72 (C(Ph)OAI),, 173.08, 164.10 (MeCANAI), 145.17, 141.75, 139.04, 138.74, 136.05, 132.51, 130.06, 129.72, 128.00, 127.35, 127.20, 126.28, 126.16, 126.08, 124.27, 123.25, 122.58 (Ar-C), 96.60, 91.16 (γ-CH), 27.52, 27.17, 27.03, 26.95 (CHMe2), 25.03, 23.75, 23.60, 23.36, 23.06, 21.68 (CHMe2), 21.41, 18.72 (N=C(CH3)).

[0035] Example 2: Aluminum hydride catalyzed reaction of benzalacetophenone and pinacolborane

[0036] Under anhydrous and anaerobic conditions, aluminum hydride catalyst 0.05 mmol was added to about 10 mL Schlenk reaction bottle, then pinacolborane 1.1 mmol was mixed uniformly, and finally benzalacetophenone 1.0 mmol was added. After heating at 80 °C for 12 h, the reaction was terminated by exposure to air, 1 mL of methanol was added to the system and stirred for half an hour, then the crude product was purified by column chromatography with petroleum ether / ethyl acetate as eluent system, and the product was obtained. The sample was weighed and dissolved in CDC13 for testing by NMR. The calculated yield was 95%. The NMR data of the product: 1H NMR (400 MHz, Chloroform-d) δ 7.28 (d, J = 7.2 Hz, 2H), 7.22 (t, J = 7.4 Hz, 2H), 7.18 - 7.11 (m, 1H), 6.47 (d, J = 15.9 Hz, 1H), 6.17 (dd, J = 15.9, 6.4 Hz, 1H), 4.47 - 4.22 (m, 1H), 1.87 (s, 1H), 1.28 (d, J = 6.4 Hz, 3H). 13 C NMR (101 MHz, CDCI3) δ 135.68, 132.55, 128.31, 127.55, 126.58, 125.42, 67.85, 22.37.

[0037] Example 3: Aluminum hydride catalyzed reaction of 4-chlorobenzalacetophenone and pinacolborane

[0038] Under anhydrous and anaerobic conditions, aluminum hydride catalyst 0.05 mmol was added to about 10 mL Schlenk reaction bottle, then pinacolborane 1.1 mmol was added and mixed evenly, finally 4-chlorobenzalacetophenone 1.0 mmol was added, heated at 80°C for 12h, then terminated by exposure to air, 1 mL of methanol was added to the system and stirred for half an hour, then the crude product was purified by column chromatography with petroleum ether / ethyl acetate as eluent system, the sample was weighed and dissolved in CDCI3 for testing by NMR. The calculated yield was 94%. The NMR data of the product: 1 H NMR (400 MHz, Chloroform-d) δ 7.18 (s, 4H), 6.41 (dd, J = 15.9, 1.3 Hz, 1H), 6.13 (dd, J = 15.9, 6.2 Hz, 1H), 4.38 (td, J = 6.4, 1.3 Hz, 1H), 1.99 (s, 1H), 1.27 (d, J = 6.4 Hz, 3H). 13 C NMR (101 MHz, CDCI3) δ 135.25, 134.25, 133.21, 128.74, 128.08, 127.67, 68.72, 23.42.

[0039] Example 4: Aluminum hydride catalyzed reaction of 3.5-dichlorobenzalacetophenone and pinacolborane

[0040] Under anhydrous and anaerobic conditions, aluminum hydride catalyst 0.05 mmol was added to about 10 mL Schlenk reaction bottle, then mixed uniformly with pinacol borane 1.1 mmol, finally added 3.5-dichloro benzylidene acetone 1.0 mmol, heated at 80 °C for 12 h, then exposed to air to terminate the reaction, 1 mL of methanol was added to the system and stirred for half an hour, then the crude product was purified by column chromatography with petroleum ether / ethyl acetate as eluent system, the sample was weighed, the product was dissolved in CDCl3, and the nuclear magnetic resonance was tested. The calculated yield was 97%. The nuclear magnetic resonance data of the product: 1 H NMR (400 MHz, Chloroform-d) δ 7.22 (d, J = 8.0 Hz, 2H), 7.00 (t, J = 8.1 Hz, 1H), 6.48 (dd, J = 16.3, 1.4 Hz, 1H), 6.21 (dd, J = 16.3, 5.9 Hz, 1H), 4.47 (pd, J = 6.4, 1.4 Hz, 1H), 2.09 - 1.70 (m, 1H), 1.33 (d, J = 6.4 Hz, 3H). 13 C NMR (101 MHz, CDCl3) δ 141.21, 133.37, 133.24, 127.36, 127.09, 121.61, 67.83, 22.16.

[0041] Example 5: Aluminum hydride compound catalyzed reaction of chalcone and pinacol borane Under anhydrous and anaerobic conditions, aluminum hydride catalyst 0.05 mmol was added to about 10 mL Schlenk reaction bottle, then mixed uniformly with pinacol borane 1.1 mmol, finally added chalcone 1.0 mmol, heated at 80 °C for 12 h, then exposed to air to terminate the reaction, 1 mL of methanol was added to the system and stirred for half an hour, then the crude product was purified by column chromatography with petroleum ether / ethyl acetate as eluent system, the sample was weighed, the product was dissolved in CDCl3, and the nuclear magnetic resonance was tested. The calculated yield was 98%. The nuclear magnetic resonance data of the product: 1 H NMR (400 MHz, Chloroform-d) δ 7.37 - 7.34 (m, 2H), 7.33 - 7.27 (m, 4H), 7.23 (tt, J = 7.4, 2.2 Hz, 3H), 7.18 - 7.12 (m, 1H), 6.61 (d, J = 15.9 Hz, 1H), 6.31 (dd, J = 15.9, 6.5 Hz, 1H), 5.31 (d, J = 6.5 Hz, 1H), 2.00 (s, 1H). 13C NMR (101 MHz, CDCI3) δ 142.79, 136.55, 131.54, 130.59, 128.67, 128.60, 127.85, 127.82, 126.64, 126.38, 75.18.

[0042] Example 6: Aluminum hydride catalyzed reaction of 4-chlorochalcone and pinacolborane

[0043] Under anhydrous and anaerobic conditions, aluminum hydride catalyst 0.05 mmol was added into a 10 ml Schlenk flask, then pinacolborane 1.1 mmol was added and mixed well, finally 4-chlorochalcone 1.0 mmol was added, after heating at 80 °C for 12 h, the reaction was terminated by exposure to air, 1 mL of methanol was added into the system and stirred for half an hour, then the crude product was purified by column chromatography with petroleum ether / ethyl acetate as eluent system, the product was obtained, sampled and weighed, and the product was dissolved in CDCI3for testing of nuclear magnetic resonance. The calculated yield was 98%. The nuclear magnetic resonance data of the product: 1 H NMR (400 MHz, Chloroform-d) δ 7.29 (dq, J = 3.6, 2.1 Hz, 2H), 7.26 (t, J = 4.4 Hz, 4H), 7.24 - 7.20 (m, 2H), 7.19 - 7.16 (m, 1H), 6.58 (dd, J = 15.9, 1.2 Hz, 1H), 6.24 (dd, J = 15.8, 6.6 Hz, 1H), 5.27 (d, J = 6.6 Hz, 1H), 2.07 (s, 1H). 13 C NMR (101 MHz, CDCI3) δ 140.15, 135.23, 132.45, 130.03, 127.74, 127.70, 127.60, 126.96, 126.68, 125.60, 73.45.

[0044] Example 7: Aluminum hydride catalyzed reaction of 4-fluorochalcone and pinacolborane

[0045] Under anhydrous and anaerobic conditions, aluminum hydride catalyst 0.05 mmol was added into a 10 ml Schlenk flask, then pinacolborane 1.1 mmol was added and mixed well, finally 4-chlorochalcone 1.0 mmol was added, after heating at 80 °C for 12 h, the reaction was terminated by exposure to air, 1 mL of methanol was added into the system and stirred for half an hour, then the crude product was purified by column chromatography with petroleum ether / ethyl acetate as eluent system, the product was obtained, sampled and weighed, and the product was dissolved in CDCI3for testing of nuclear magnetic resonance. The calculated yield was 98%. The nuclear magnetic resonance data of the product: 1H NMR (400 MHz, Chloroform-d) δ 7.35 - 7.28 (m, 4 H), 7.23 (t, J = 7.4 Hz, 2 H), 7.19 - 7.16 (m, 1 H), 6.97 (t, J = 8.7 Hz, 2 H), 6.59 (d, J = 15.8 Hz, 1 H), 6.27 (dd, J = 15.8, 6.5 Hz, 1 H), 5.29 (d, J = 6.5 Hz, 1 H), 2.02 (s, 1 H). 13 C NMR (101 MHz, CDC13) δ 163.58, 161.14, 138.54, 136.37, 131.33, 130.81, 128.64, 128.12, 127.95, 126.64, 115.56, 115.35, 74.51.

[0046] Example 8: Aluminum hydride catalyzed reaction of 4-methoxychalcone and pinacolborane

[0047] Under anhydrous and anaerobic conditions, aluminum hydride catalyst 0.05 mmol was added to about 10 mL Schlenk reaction bottle, then pinacolborane 1.1 mmol was added and mixed evenly, finally 4-methoxychalcone 1.0 mmol was added, heated at 80°C for 12h, then exposed to air to terminate the reaction, 1 mL of methanol was added to the system and stirred for half an hour, then the crude product was purified by column chromatography with petroleum ether / ethyl acetate as eluent system, the sample was weighed and dissolved in CDC13 for testing by NMR. The calculated yield was 97%. The NMR data of the product: 1 H NMR (400 MHz, Chloroform-d) δ 7.34 - 7.27 (m, 2 H), 7.23 (ddd, J = 7.8, 6.2, 1.4 Hz, 3 H), 7.17 (d, J = 9.4 Hz, 2 H), 6.85 - 6.79 (m, 2 H), 6.60 (dd, J = 15.9, 1.3 Hz, 1 H), 6.31 (dd, J = 15.8, 6.3 Hz, 1 H), 5.28 (dd, J = 6.8, 2.7 Hz, 1 H), 3.73 (d, J = 4.0 Hz, 3 H), 1.49 (s, 1 H). 13 C NMR (101 MHz, CDC13) δ 158.26, 135.59, 133.99, 130.67, 129.18, 127.54, 126.69, 125.57, 125.28, 113.00, 73.66, 54.30.

[0048] Example 9: Aluminum hydride catalyzed reaction of 4'-fluorochalcone and pinacolborane

[0049] Under anhydrous and anaerobic conditions, aluminum hydride catalyst 0.05 mmol was added to about 10 ml Schlenk reaction bottle, then pinacol borane 1.1 mmol was added, mixed evenly, finally 4'-fluorochalcone 1.0 mmol was added, heated at 80°C for 12h, exposed to air to terminate the reaction, 1 mL of methanol was added to the system and stirred for half an hour, then the crude product was purified by column chromatography with petroleum ether / ethyl acetate as the eluent system, and the product was obtained. The sample was weighed, the product was dissolved in CDCl3, and the nuclear magnetic resonance was tested. The calculated yield was 96%. The nuclear magnetic resonance data of the product: 1 H NMR (400 MHz, Chloroform-d) δ 7.35-7.31 (m, 2H), 7.31-7.27 (m, 2H), 7.27-7.21 (m, 3H), 6.90 (t, J = 8.7 Hz, 2H), 6.55 (dd, J = 15.9, 1.3 Hz, 1H), 6.20 (dd, J = 15.8, 6.5 Hz, 1H), 5.35-5.20 (m, 1H), 2.12 (s, 1H) 13 C NMR (101 MHz, CDCl3) δ 141.55, 134.02, 132.35, 131.12, 128.15, 127.69, 127.67, 126.90, 126.78, 125.31, 73.95.

[0050] Example 10: Aluminum hydride compound catalyzing the reaction of 4'-chlorochalcone and pinacol borane

[0051] Under anhydrous and anaerobic conditions, aluminum hydride catalyst 0.05 mmol was added to about 10 ml Schlenk reaction bottle, then pinacol borane 1.1 mmol was added, mixed evenly, finally 4'-chlorochalcone 1.0 mmol was added, heated at 80°C for 12h, exposed to air to terminate the reaction, 1 mL of methanol was added to the system and stirred for half an hour, then the crude product was purified by column chromatography with petroleum ether / ethyl acetate as the eluent system, and the product was obtained. The sample was weighed, the product was dissolved in CDCl3, and the nuclear magnetic resonance was tested. The calculated yield was 95%. The nuclear magnetic resonance data of the product: 1 H NMR (400 MHz, Chloroform-d) δ 7.36-7.26 (m, 4H), 7.24-7.15 (m, 5H), 6.55 (dd, J = 15.8, 1.3 Hz, 1H), 6.26 (dd, J = 15.8, 6.3 Hz, 1H), 5.28 (dd, J = 6.3, 1.3 Hz, 1H), 2.16-2.00 (m, 1H). 13C NMR (101MHz, CDCl3) δ162.60,160.15,141.70,131.68,130.24,128.30,127.64,127.14,127.06,126.84,125.29,114.56,114.34,74.02.

[0052] Example 11: Reaction of 4-phenyl-3-butyn-2-one and pinacolborane catalyzed by aluminum hydride

[0053] Under anhydrous and oxygen-free conditions, in a glove box under nitrogen protection, 0.05 mmol of aluminum hydrogen catalyst was added to a Schlenk flask containing approximately 10 mL of solution. Then, 1.1 mmol of pinacol borane was added and mixed thoroughly. Finally, 1.0 mmol of 4-phenyl-3-butyn-2-one was added. The reaction was heated at 80 °C for 12 h, and then terminated by exposure to air. 1 mL of methanol was added to the system and stirred for half an hour. The crude product was purified by column chromatography using petroleum ether / ethyl acetate as the elution system. The product was sampled, weighed, dissolved in CDCl3, and analyzed for NMR. The calculated yield was 93%. NMR data of the product: 1 H NMR (400MHz, Chloroform-d) δ7.49–7.40(m,2H),7.30(dd,J=4.9,2.1Hz,3H),4.76(d,J=6.6Hz,1H),1.56(d,J=6.6Hz,3H). 13 C NMR (101MHz, CDCl3) δ131.67,128.40,128.30,122.60,90.94,84.05,58.90,24.42.

[0054] Example 12: Reaction of cyclohexenone and pinacolborane catalyzed by aluminum hydride

[0055] Under anhydrous and oxygen-free conditions, in a glove box under nitrogen protection, 0.05 mmol of aluminum hydrogen catalyst was added to approximately 10 mL of Schlenk reaction flask, followed by 1.1 mmol of pinacol borane and mixing thoroughly. Finally, 1.0 mmol of cyclohexenone was added. The reaction was heated at 80 °C for 12 h, then terminated by exposure to air. After stirring for half an hour with 1 mL of methanol added, the crude product was purified by column chromatography using petroleum ether / ethyl acetate as the elution system. The product was sampled, weighed, dissolved in CDCl3, and analyzed for NMR. The calculated yield was 94%. NMR data of the product: 1H NMR(400MHz,Chloroform-d)δ5.76–5.67(m,1H),5.65–5.57(m,1H),4.48(d,J=5.0Hz,1H),1.92( dd,J=17.2,11.9Hz,1H),1.83–1.64(m,3H),1.64–1.53(m,1H),1.53–1.41(m,1H),1.18(s,24H). 13 C NMR (101MHz, CDCl3) δ149.54,129.23,127.86,81.52,67.08,29.78,23.90,23.58,18.00.

[0056] Example 13: Reaction of cyclopentenone and pinacolborane catalyzed by aluminum hydride

[0057] Under anhydrous and oxygen-free conditions, in a glove box under nitrogen protection, 0.05 mmol of aluminum hydrogen catalyst was added to approximately 10 mL of Schlenk reaction flask, followed by 1.1 mmol of pinacol borane and mixing thoroughly. Finally, 1.0 mmol of cyclopentenone was added. The reaction was heated at 80 °C for 12 h, then terminated by exposure to air. After stirring for half an hour with 1 mL of methanol added, the crude product was purified by column chromatography using petroleum ether / ethyl acetate as the elution system. The product was sampled, weighed, dissolved in CDCl3, and analyzed for NMR. The calculated yield was 90%. NMR data of the product: 1 H NMR(400MHz,Chloroform-d)δ5.97–5.85(m,1H),5.73(dd,J=5.5,2.3Hz,1H),5.10(dd,J=4.3, 2.4Hz,1H),2.52–2.33(m,1H),2.24–2.07(m,2H),1.69(dq,J=13.0,3.9Hz,1H),1.18(s,12H). 13 C NMR (101MHz, CDCl3) δ134.22,130.92,81.56,78.76,31.07,29.99,23.60,23.58.

[0058] Example 14: Reaction of methylcyclopentenone and pinacolborane catalyzed by aluminum hydride

[0059] Under anhydrous and oxygen-free conditions, in a glove box under nitrogen protection, 0.05 mmol of aluminum hydrogen catalyst was added to approximately 10 mL of Schlenk reaction flask, followed by 1.1 mmol of pinacol borane and thorough mixing. Finally, 1.0 mmol of methylcyclopentenone was added. The reaction was heated at 80 °C for 12 h, then terminated by exposure to air. After stirring for half an hour with 1 mL of methanol added, the crude product was purified by column chromatography using petroleum ether / ethyl acetate as the elution system. The product was sampled, weighed, dissolved in CDCl3, and analyzed for NMR. The calculated yield was 87%. NMR data of the product: 1 H NMR (400MHz, Chloroform-d) δ5.35 (s, 1H), 5.12–4.92 (m, 1H), 2.35 (dq, J = 11.0, 5. 9Hz,1H),2.17(d,J=7.7Hz,1H),2.07(s,1H),1.68(s,3H),1.18(d,J=8.0Hz,12H). 13 C NMR (101MHz, CDCl3) δ145.87,130.66,126.18,82.84,82.42,80.29,35.14,33.04,24.54,24.49,16.64.

[0060] Example 15: Reaction of verbenatone and pinacolborane catalyzed by aluminum hydride

[0061] Under anhydrous and oxygen-free conditions, in a glove box under nitrogen protection, 0.05 mmol of aluminum hydrogen catalyst was added to approximately 10 mL of Schlenk reaction flask, followed by 1.1 mmol of pinacol borane and mixing thoroughly. Finally, 1.0 mmol of verbenone was added. The reaction was heated at 80 °C for 12 h, then terminated by exposure to air. After stirring for half an hour with 1 mL of methanol added, the crude product was purified by column chromatography using petroleum ether / ethyl acetate as the elution system. The product was sampled, weighed, dissolved in CDCl3, and analyzed for NMR. The calculated yield was 93%. NMR data of the product: 1 H NMR(400MHz,Chloroform-d)δ5.50–5.32(m,1H),4.67(s,2H),4.20–4.04(m,1H),2.26–2.15(m,1H),2.09(ddt,J=12.2,5.9,2.2Hz,1H),1. 99(tt,J=3.4,1.7Hz,1H),1.93–1.82(m,1H),1.69(dq,J=2.8,1.4Hz,3H),1.67(d,J=1.2Hz,2H),1.52(d,J=5.5Hz,1H),1.47–1.37(m,1H). 13C NMR (101MHz, CDCl3) δ148.99,136.16,123.88,109.15,70.93,40.46,38.03,31.04,20.63,18.95.

[0062] Example 15: Reaction of L-carvone and pinacolborane catalyzed by aluminum hydride

[0063] Under anhydrous and oxygen-free conditions, in a glove box under nitrogen protection, 0.05 mmol of aluminum hydrogen catalyst was added to approximately 10 mL of Schlenk reaction flask, followed by 1.1 mmol of pinacol borane and mixing thoroughly. Finally, 1.0 mmol of levamisole was added. The reaction was heated at 80 °C for 12 h, then terminated by exposure to air. After stirring for half an hour with 1 mL of methanol added, the crude product was purified by column chromatography using petroleum ether / ethyl acetate as the elution system. The product was sampled, weighed, dissolved in CDCl3, and analyzed for NMR. The calculated yield was 93%. NMR data of the product: 1 H NMR(400MHz,Chloroform-d)δ5.30(dq,J=3.1,1.6Hz,1H),4.39(td,J=3.1,1.6Hz,1H),2.43–2.29(m,1H),2.22(dd,J=3.5,2.1 Hz,1H),1.90(td,J=5.5,1.4Hz,1H),1.66(t,J=1.7Hz,3H),1.64–1.58(m,1H),1.28(s,3H),1.24(d,J=9.1Hz,1H),1.01(s,3H). 13 C NMR (101MHz, CDCl3) δ147.38,119.33,73.56,48.21,47.75,38.95,35.58,26.88,22.64,22.60.

[0064] Example 16: The reaction of testosterone and pinacolborane catalyzed by aluminum hydride

[0065] Under anhydrous and oxygen-free conditions, in a glove box under nitrogen protection, 0.05 mmol of aluminum hydrogen catalyst was added to approximately 10 mL of Schlenk reaction flask, followed by 1.1 mmol of pinacol borane and thorough mixing. Finally, 1.0 mmol of testosterone was added, and the reaction was terminated by heating at 80 °C for 12 h and then exposing to air. After stirring for half an hour with 1 mL of methanol added, the crude product was purified by column chromatography using petroleum ether / ethyl acetate as the elution system. The product was sampled, weighed, dissolved in CDCl3, and analyzed for NMR. The calculated yield was 93%. NMR data of the product: 1H NMR(400MHz,Chloroform-d)δ5.28(s,1H),4.14(d,J=8.0Hz,1H),3.60(s,1H),2.18(d,J=13.8Hz,1H),1.99(d,J=33.8Hz,6H),1.89–1.68(m,3H),1.65–1.33(m,4H),δ1.64–1.34(m,10H).1.06(s,3H),0.97–0.83(m,2H),0.76(s,3H). 13 C NMR(101MHz,CDCl3)δ147.47,123.53,81.86,67.94,54.60,50.74,42.89,37.43,36.64,36.01,35.43,32.63,32.10,30.52,29.52,23.39,20.64,18.97,11.06。

Claims

1. An aluminum hydride compound having the following structure Dipp = 2,6-iPr2C6H 3。 2. A process for the preparation of the aluminum hydride compound of claim 1, characterized in that, comprising the following steps: (1) under nitrogen protection, refluxing 1-phenyl-1,3-butanedione and 2,6-diisopropylaniline with hydrochloric acid in ethanol solvent at 80°C for 36h at a molar ratio of 1:1:0.001, after the reaction is completed, the reaction solution is concentrated and crystallized in a refrigerator overnight, the crystals are filtered and washed with ice methanol, and then the solvent is removed to obtain pure ligand; (2) under anhydrous and anaerobic conditions, slowly adding trimethylamine aluminum hydride to a toluene solution of the above ligand in a Schlenk reaction bottle under nitrogen protection at low temperature, the molar ratio of the two is 2:1, stirring overnight at room temperature, standing and filtering, then concentrating the toluene and placing it in a low-temperature refrigerator the next day to obtain a large amount of crystals, which is the aluminum hydride compound.

3. The use of the aluminum hydride compound of claim 1 in the reduction of unsaturated ketones.

4. Use according to claim 3, characterized in that: The unsaturated ketone is selected from one of aromatic unsaturated ketones, aliphatic unsaturated ketones; the borane is pinacol borane.

5. Use according to claim 4, characterized in that: The aromatic unsaturated ketone compound is selected from benzalacetone, 4-chlorobenzalacetone, 3,5-dichlorobenzalacetone, chalcone, 4-chlorochalcone, 4-fluorochalcone, 4-methoxychalcone, 4'-fluorochalcone, 4'-chlorochalcone, 4-phenyl-3-butyn-2-one.

6. Use according to claim 4, characterized in that: The aliphatic unsaturated ketone compound is selected from cyclohexenone, cyclopentenone, 3-methylcyclopentenone, verbenone, levorotatory carvone, testosterone.

7. Use according to claim 3, characterized in that: The molar ratio of the aluminum hydride compound: unsaturated ketone: borane is 0.05:1:1, the boron hydride reaction temperature is 80°C, and the time is 12h.

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