A method for catalytic hydroboration of nitrile compounds

Abstract

This invention provides a method for the catalytic hydroboration of nitrile compounds, belonging to the field of nitrile reduction technology. The method uses nitrile compounds as substrates, molybdenum hexacarbonyl as a catalyst, and pinacolborane as a hydrogen source, with the hydroboration reaction occurring at 78-82°C for 7.5-8.5 h. The reaction utilizes molybdenum hexacarbonyl as a catalyst, which is simple and readily available, requiring no complex synthesis. Furthermore, the reaction process does not require the participation of ligands. Using pinacolborane as a hydrogen source eliminates the need for strictly nitrogen-protected experimental conditions, enabling the hydroboration of nitriles. The substrate applicability is broad, applicable not only to aromatic nitriles but also to aliphatic nitriles and even some dinitriles. The reaction process does not require solvents, making it environmentally friendly. The corresponding hydroboration product is obtained directly after the reaction without further purification, and the reaction yield is high, ranging from 84-100%.

Description

Technical Field

[0001] This invention relates to a method for catalytic hydroboration of nitrile compounds, belonging to the field of nitrile reduction technology. Background Technology

[0002] The reduction of nitrile compounds to primary amines is an important method for amine synthesis. However, due to the high carbon-nitrogen bond dissociation energy (750.0 kJ / mol) of nitrile compounds, they are difficult to reduce under conventional reaction conditions and often require a catalyst. Hydrogenation of nitrile compounds can selectively generate primary amines, but the reaction requires high temperature and pressure conditions and may produce byproducts such as imines, secondary amines, and tertiary amines. Therefore, catalytic reduction of nitrile compounds to primary amines under mild reaction conditions has always been a research challenge. The hydrosilylation and hydroboration reactions of nitrile compounds to generate amine derivatives are increasingly favored by scientists due to their mild reaction conditions and high selectivity. For nitrile compounds, hydrosilylation can yield both monosilane-substituted imines and disilane-substituted primary amines. Compared to hydrosilylation, hydroboration has a greater advantage in chemoselectivity and has therefore been extensively studied (J. Org. Chem., 2016, 81, 11153–11161.).

[0003] Existing technologies employ transition metal catalysis for the hydroboration of nitrile compounds. Noble metals such as Ru and transition metals like Fe, Co, Ni, Mo, and Mn have been successfully used in the hydroboration of nitrile compounds (Org. Biomol. Chem., 2022, 20, 3675–3702). However, these metal catalysts often require one or more steps in their synthesis. Although commercially available Ni(acac) can catalyze the hydroboration of nitriles, a more reactive borane (catecholborane) is required as the hydrogen source (Catal. Sci. Technol., 2017, 7, 3196–3199.).

[0004] There are few reports on the hydroboration of nitrile catalyzed by group VI metal compounds. In 2012, Nikonov's research group synthesized a tetravalent molybdenum compound Mo(PMe3)3NArHCl as a catalyst for the hydroboration of nitrile (Chem. Commun. 2012, 48(3), 455-457.). This was the first report on the hydroboration of nitrile, indicating that molybdenum has great potential in the field of catalytic hydroboration of nitrile. However, this catalytic system can only catalyze the reaction of acetonitrile or benzonitrile with catecholborane to generate boronamine compounds, which limits the substrate applicability; the synthesis of the catalyst is complex, requiring more than three synthetic routes; the catalyst contains multiple phosphorus ligands, which can easily cause environmental pollution; and the catalyst is sensitive to air, difficult to store, and the reaction requires strict anhydrous and oxygen-free conditions.

[0005] Professor Song Heng's research group at Jiangsu University of Science and Technology reported an example of a W(CO)4(NCMe)2 / HBPin system based on tungsten chemistry (Chem. Commun., 2024, 60, 5026.). This catalytic system is sensitive to air, and experimental operations generally require nitrogen protection. Furthermore, the catalyst also needs to be synthesized. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a method for the catalytic hydroboration reaction of nitrile compounds, using molybdenum hexacarbonyl as a catalyst that is stable in air, and pinacolborane as a hydrogen source. The reaction process does not require strictly anhydrous and oxygen-free experimental conditions, nor does it require a solvent, thus achieving the selective reduction of nitrile compounds to generate diborane-substituted primary amine compounds.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0008] A method for catalytic hydroboration of nitrile compounds, using nitrile compounds as substrates, molybdenum hexacarbonyl as catalyst, and pinacolborane as hydrogen source, wherein the hydroboration reaction is carried out at 78-82℃ for 7.5-8.5 h.

[0009] The molar ratio of hexacarbonylmolybdenum to nitrile compounds is 1-2:20, and the molar ratio of nitrile compounds to pinacolborane is 1:3-6.

[0010] The nitrile compound is one of the following: p-methylbenzonitrile, benzonitrile, m-methylbenzonitrile, o-methylbenzonitrile, p-fluorobenzonitrile, p-chlorobenzonitrile, p-bromobenzonitrile, p-iodobenzonitrile, p-trifluoromethylbenzonitrile, p-methoxybenzonitrile, p-tert-butylbenzonitrile, p-fluorophenylacetonitrile, p-phthalonitrile, 2-cyanofuran, 2-cyanothiophene, cyclohexylbenzonitrile, and acetonitrile.

[0011] The borohydride products corresponding to the above-mentioned nitrile compounds are N,N-diborane-p-methylphenethylamine, N,N-diborane-phenethylamine, N,N-diborane-m-methylphenethylamine, N,N-diborane-o-methylphenethylamine, N,N-diborane-p-fluorophenethylamine, N,N-diborane-p-chlorophenethylamine, N,N-diborane-p-bromophenethylamine, N,N-diborane-p-iodophenethylamine, N,N-diborane-p-trifluoromethylphenethylamine, N,N-diborane-p-methoxyphenethylamine, N,N-diborane-p-tert-butylphenethylamine, N,N-diborane-p-fluorophenoxypropylamine, N,N-diborane-p-phenylenediamine, N,N-diborane-2-furan ethylamine, N,N-diborane-2-thiophene ethylamine, N,N-diborane-cyclohexylethylamine, and N,N-diborane ethylamine.

[0012] Compared with the prior art, the present invention achieves the following beneficial effects:

[0013] The reaction of this invention uses molybdenum hexacarbonyl as a catalyst, which is simple and readily available, does not require complex synthesis, and does not require the participation of ligands in the reaction process.

[0014] This invention uses pinacolborane as a hydrogen source, and the reaction process does not require strictly anhydrous and oxygen-free experimental conditions to achieve the hydroboration of nitriles. It has a wide range of applicable substrates, and the reaction is applicable not only to aromatic nitriles, but also to aliphatic nitriles and even some dinitriles. It also has good functional group compatibility with different substituents such as halogens, methoxy groups, alkyl groups, trifluoromethyl groups, etc.

[0015] The present invention does not require a solvent during the reaction process, making it environmentally friendly; the corresponding borohydride product can be obtained without further purification after the reaction is completed, and the reaction yield is high, ranging from 84% to 100%. Attached Figure Description

[0016] Figure 1 The 1H NMR spectrum of the borohydride product in Example 3;

[0017] Figure 2 The carbon NMR spectrum of the borohydride product in Example 3;

[0018] Figure 3 The 1H NMR spectrum of the borohydride product in Example 11;

[0019] Figure 4 The carbon NMR spectrum of the borohydride product in Example 11;

[0020] Figure 5 The 1H NMR spectrum of the borohydride product in Example 12;

[0021] Figure 6 The carbon NMR spectrum of the borohydride product in Example 12;

[0022] Figure 7 The 1H NMR spectrum of the borohydride product in Example 13;

[0023] Figure 8 The carbon NMR spectrum of the borohydride product in Example 13;

[0024] Figure 9 The 1H NMR spectrum of the borohydride product in Example 14;

[0025] Figure 10 The carbon NMR spectrum of the borohydride product in Example 14;

[0026] Figure 11 The 1H NMR spectrum of the borohydride product in Example 15;

[0027] Figure 12 The carbon NMR spectrum of the borohydride product in Example 15;

[0028] Figure 13 The 1H NMR spectrum of the borohydride product in Example 16;

[0029] Figure 14 The carbon NMR spectrum of the borohydride product in Example 16;

[0030] Figure 15 The 1H NMR spectrum of the borohydride product in Example 17;

[0031] Figure 16 The carbon NMR spectrum of the borohydride product in Example 17;

[0032] Figure 17 The 1H NMR spectrum of the borohydride product in Example 18;

[0033] Figure 18 The carbon NMR spectrum of the borohydride product in Example 18;

[0034] Figure 19 The 1H NMR spectrum of the borohydride product in Example 19;

[0035] Figure 20 The carbon NMR spectrum of the borohydride product in Example 19;

[0036] Figure 21 The 1H NMR spectrum of the borohydride product of Example 20;

[0037] Figure 22 The carbon NMR spectrum of the borohydride product in Example 20;

[0038] Figure 23 The 1H NMR spectrum of the borohydride product in Example 21;

[0039] Figure 24 The carbon NMR spectrum of the borohydride product in Example 21;

[0040] Figure 25 The 1H NMR spectrum of the borohydride product in Example 22;

[0041] Figure 26 The carbon NMR spectrum of the borohydride product in Example 22;

[0042] Figure 27 The 1H NMR spectrum of the borohydride product in Example 23;

[0043] Figure 28 The carbon NMR spectrum of the borohydride product in Example 23;

[0044] Figure 29 The 1H NMR spectrum of the borohydride product in Example 24;

[0045] Figure 30 The carbon NMR spectrum of the borohydride product in Example 24;

[0046] Figure 31 The 1H NMR spectrum of the borohydride product of Example 25;

[0047] Figure 32 The carbon NMR spectrum of the borohydride product in Example 25;

[0048] Figure 33 The 1H NMR spectrum of the borohydride product in Example 26;

[0049] Figure 34 The image shows the carbon NMR spectrum of the borohydride product from Example 26. Detailed Implementation

[0050] Example 1

[0051] Add 48 μL (0.4 mmol) of p-toluenebenzonitrile, 175 μL (1.2 mmol) of HBpin, and 5.3 mg (5 mol%) of Mo(CO)6 to a 5 mL reaction tube and heat at 30 °C for 8 hours. Post-reaction processing: Add 75 μL (0.4 mmol) of tetraethylsilane directly to the reaction solution as an internal standard, then add 0.6 mL of deuterated chloroform to dissolve and mix the reactants thoroughly. Transfer the solution to an NMR tube for NMR analysis. The NMR yield of the borohydride product was less than 5%.

[0052] Example 2

[0053] Add 48 μL (0.4 mmol) of p-toluenebenzonitrile, 175 μL (1.2 mmol) of HBpin, and 5.3 mg (5 mol%) of Mo(CO)6 to a 5 mL reaction tube and heat at 50 °C for 8 hours. Post-reaction processing: Add 75 μL (0.4 mmol) of tetraethylsilane directly to the reaction solution as an internal standard, then add 0.6 mL of deuterated chloroform to dissolve and mix the reactants thoroughly. Transfer the solution to an NMR tube for NMR analysis. The NMR yield of the borohydride product was found to be 78%.

[0054] Example 3

[0055] Add 48 μL (0.4 mmol) of p-toluenebenzonitrile, 175 μL (1.2 mmol) of HBpin, and 5.3 mg (5 mol%) of Mo(CO)6 to a 5 mL reaction tube and heat at 80 °C for 8 hours. Post-reaction processing: Add 75 μL (0.4 mmol) of tetraethylsilane directly to the reaction solution as an internal standard, then add 0.6 mL of deuterated chloroform to dissolve and mix the reactants thoroughly. Transfer the solution to an NMR tube for NMR analysis. The NMR yield of the borohydride product was found to be 99%.

[0056] Figure 1 The image shows the 1H NMR spectrum of the target product N,N-diborane-p-methylphenethylamine obtained in Example 3. Figure 2 The image shows the carbon NMR spectrum of the target product obtained in Example 3. Figure 1 and Figure 2 It can be seen that the product has the correct structure.

[0057] 1 H NMR (400 MHz, CDCl3) δ 7.19 (d, J = 7.4 Hz, 2H), 7.03 (d, J = 7.5 Hz, 2H), 4.18 (s, 2H), 2.28 (s, 3H), 1.19 (s, 24H). 13 C NMR (101 MHz, CDCl3) δ140.12 (s), 135.36 (s), 128.49 (s), 127.50 (s), 82.24 (s), 46.93 (s), 24.51 (s), 21.04 (s).

[0058] Based on the analysis of Examples 1-3, it was found that the borohydride reaction can hardly occur at 30°C. As the temperature increases, the reaction yield increases, and 80°C is the optimal reaction temperature.

[0059] Example 4

[0060] To a 5 mL reaction tube, p-toluenenitrile (48 μL, 0.4 mmol), HBpin (175 μL, 1.2 mmol), and Mo(CO)6 (5.3 mg, 5 mol%) were added, along with 0.5 mL of tetrahydrofuran as solvent. The mixture was heated at 80 °C for 8 hours. Post-reaction processing: The solvent was removed under reduced pressure. Tetraethylsilane (75 μL, 0.4 mmol) was added directly to the reaction tube as an internal standard, followed by 0.6 mL of deuterated chloroform. The reactants were dissolved and mixed thoroughly, then transferred to an NMR tube for NMR analysis. The NMR yield of the reaction was found to be 81%.

[0061] Example 5

[0062] To a 5 mL reaction tube, p-toluenenitrile (48 μL, 0.4 mmol), HBpin (175 μL, 1.2 mmol), and Mo(CO)6 (5.3 mg, 5 mol%) were added, along with 0.5 mL of dichloromethane as the solvent. The mixture was heated at 80 °C for 8 hours. Post-reaction processing: The solvent was removed under reduced pressure. Tetraethylsilane (75 μL, 0.4 mmol) was added directly to the reaction tube as an internal standard, followed by 0.6 mL of deuterated chloroform. The reactants were dissolved and mixed thoroughly, then transferred to an NMR tube for NMR analysis. The NMR yield of the reaction was found to be 49%.

[0063] Based on the analysis of Examples 3-5, it can be seen that the optimal conditions for this reaction are solvent-free. Although moderate to high yields can be obtained when tetrahydrofuran and dichloromethane are used as solvents, these solvents need to be removed during post-processing.

[0064] Example 6

[0065] Add 48 μL (0.4 mmol) of p-toluenebenzonitrile, 175 μL (1.2 mmol) of HBpin, and 7 mg (5 mol%) of W(CO)6 to a 5 mL reaction tube and heat at 80 °C for 8 hours. Post-reaction processing: Add 75 μL (0.4 mmol) of tetraethylsilane as an internal standard directly to the reaction tube, followed by 0.6 mL of deuterated chloroform to dissolve and mix the reactants thoroughly. Transfer the solution to an NMR tube for NMR analysis. The NMR yield of the borohydride product was 44%.

[0066] Example 7

[0067] Add 48 μL (0.4 mmol) of p-toluenebenzonitrile, 175 μL (1.2 mmol) of HBpin, and 4.4 mg (5 mol%) of Cr(CO)6 to a 5 mL reaction tube and heat at 80 °C for 8 hours. Post-reaction processing: Add 75 μL (0.4 mmol) of tetraethylsilane as an internal standard directly to the reaction tube, followed by 0.6 mL of deuterated chloroform. Dissolve and mix the reactants thoroughly, transfer the solution to an NMR tube, and perform NMR analysis. The final NMR yield of the borohydride product was 60%.

[0068] Based on the analysis of Examples 3, 6, and 7, the catalytic effect of molybdenum hexacarbonyl is significantly improved compared to hexacarbonyltungsten or hexacarbonylchromium, which belong to the same metal carbonyl compound family as molybdenum.

[0069] Example 8

[0070] Add 48 μL (0.4 mmol) of p-toluenebenzonitrile, 175 μL (1.2 mmol) of HBpin, and 6.6 mg (5 mol%) of molybdenum acetylacetonate to a 5 mL reaction tube and heat at 80 °C for 8 hours. Post-reaction processing: Add 75 μL (0.4 mmol) of tetraethylsilane directly to the reaction tube as an internal standard, then add 0.6 mL of deuterated chloroform to dissolve and mix the reactants thoroughly. Transfer the solution to an NMR tube for NMR analysis. The final NMR yield of the product was 21%.

[0071] Example 9

[0072] Add 48 μL (0.4 mmol) of p-toluenebenzonitrile, 175 μL (1.2 mmol) of HBpin, and 2.5 mg (5 mol%) of molybdenum dioxide to a 5 mL reaction tube and heat at 80 °C for 8 hours. Post-reaction processing: Add 75 μL (0.4 mmol) of tetraethylsilane as an internal standard directly to the reaction tube, then add 0.6 mL of deuterated chloroform to dissolve and mix the reactants thoroughly. Transfer the solution to an NMR tube for NMR analysis. The final NMR yield of the product was 10%.

[0073] Example 10

[0074] Add 48 μL (0.4 mmol) of p-toluenebenzonitrile, 175 μL (1.2 mmol) of HBpin, and sodium molybdate (4.1 mg, 5 mol%) to a 5 mL reaction tube and heat at 80 °C for 8 hours. Post-reaction processing: Add 75 μL (0.4 mmol) of tetraethylsilane as an internal standard directly to the reaction tube, then add 0.6 mL of deuterated chloroform to dissolve and mix the reactants thoroughly. Transfer the solution to an NMR tube for NMR analysis. The final NMR yield of the product was 19%.

[0075] In conjunction with Examples 3, 8, 9, and 10, when molybdenum compounds of different valence states (tetravalent molybdenum and hexavalent molybdenum) were used as catalysts, hexacarbonyl molybdenum showed the best reaction performance, indicating that low-valence molybdenum compounds are more conducive to the oxidative addition of pinacolborane to the metal center.

[0076] The products prepared in Examples 1-10 were all N,N-diborane-p-methylphenethylamine.

[0077] Based on the analysis of Examples 1-10, the optimal reaction conditions for the catalytic hydroboration of nitrile are: 5 mol% Mo(CO)6 as catalyst, 1.2 mmol HBpin added, 80 °C, and solvent-free reaction for 8 h.

[0078] Example 11

[0079] Benzonitrile (41 μL, 0.4 mmol), HBpin (175 μL, 1.2 mmol), and Mo(CO)6 (5.3 mg, 5 mol%) were added to a 5 mL reaction tube, and the mixture was heated at 80 °C for 8 hours. Post-reaction processing: Tetraethylsilane (75 μL, 0.4 mmol) was added directly to the reaction solution as an internal standard, followed by 0.6 mL of deuterated chloroform. The reactants were dissolved and mixed thoroughly, transferred to an NMR tube, and subjected to NMR analysis. The final NMR yield of the reaction was 96%.

[0080] Figure 3 The image shows the 1H NMR spectrum of the target product N,N-diborane phenethylamine obtained in Example 11. Figure 4 The image shows the carbon NMR spectrum of the target product obtained in Example 11. Figure 3 and Figure 4 It can be seen that the product has the correct structure.

[0081] 1 H NMR (400 MHz, CDCl3) δ 7.29 (d, J = 7.3 Hz, 2H), 7.22 (t, J = 7.2 Hz, 2H), 7.13 (t, J = 6.7 Hz, 1H), 4.23 (s, 2H), 1.20 (d, J = 11.6 Hz, 24H). 13 C NMR (101 MHz, CDCl3) δ 143.05 (s), 127.77 (s), 127.51 (s), 126.08 (s), 82.26 (s), 47.26 (s), 24.50 (d, J = 5.1 Hz).

[0082] Example 12

[0083] To a 5 mL reaction tube, add m-methylbenzonitrile (46 μL, 0.4 mmol), HBpin (175 μL, 1.2 mmol), and Mo(CO)6 (5.3 mg, 5 mol%), and heat at 80 °C for 8 hours. Post-reaction processing: Add tetraethylsilane (75 μL, 0.4 mmol) directly to the reaction solution as an internal standard, then add 0.6 mL of deuterated chloroform to dissolve and mix the reactants thoroughly. Transfer the solution to an NMR tube for NMR analysis. The final NMR yield of the reaction was 91%.

[0084] Figure 5 The image shows the 1H NMR spectrum of the target product N,N-diborane-m-methylphenethylamine obtained in Example 12. Figure 6 The image shows the carbon NMR spectrum of the target product obtained in Example 12. Figure 5 and Figure 6 It can be seen that the product has the correct structure.

[0085] 1 H NMR (400 MHz, CDCl3) δ 7.17 – 7.03 (m, 3H), 6.95 (d, J = 6.4 Hz, 1H), 4.20 (s, 2H), 2.29 (s, 3H), 1.19 (s, 23H). 13 C NMR (101 MHz, CDCl3) δ 142.96(s), 137.13 (s), 128.31 (s), 127.71 (s), 126.77 (s), 124.54 (s), 82.26 (s), 47.14 (s), 24.49 (s), 21.37 (s).

[0086] Example 13

[0087] Add 47 μL (0.4 mmol) of o-methylbenzonitrile, 175 μL (1.2 mmol) of HBpin, and 5.3 mg (5 mol%) of Mo(CO)6 to a 5 mL reaction tube and heat at 80 °C for 8 hours. Post-reaction processing: Add 75 μL (0.4 mmol) of tetraethylsilane directly to the reaction solution as an internal standard, then add 0.6 mL of deuterated chloroform to dissolve and mix the reactants thoroughly. Transfer the solution to an NMR tube for NMR analysis. The NMR yield of the reaction was found to be 90%.

[0088] Figure 7 The image shows the 1H NMR spectrum of the target product N,N-diborane-o-methylphenethylamine obtained in Example 13. Figure 8 The image shows the carbon NMR spectrum of the target product obtained in Example 13. Figure 7 and Figure 8 It can be seen that the product has the correct structure.

[0089] 1 H NMR (400 MHz, CDCl3) δ 7.02 (d, J = 7.3 Hz, 1H), 6.90 – 6.85 (m, 1H), 6.84 (s, 2H), 4.01 (s, 2H), 2.08 (s, 3H), 0.96 (s, 23H). 13C NMR (101 MHz, CDCl3) δ 140.58 (s), 135.03 (s), 129.44 (s), 126.15 (s), 125.70 (s), 125.34(s), 82.19 (s), 44.73 (s), 24.83 (s), 24.43 (d, J = 12.2 Hz), 19.08 (s).

[0090] Example 14

[0091] To a 5 mL reaction tube, p-fluorobenzonitrile (48 mg, 0.4 mmol), HBpin (175 μL, 1.2 mmol), and Mo(CO)₆ (5.3 mg, 5 mol%) were added, and the mixture was heated at 80 °C for 8 hours. Post-reaction processing: Tetraethylsilane (75 μL, 0.4 mmol) was added directly to the reaction solution as an internal standard, followed by 0.6 mL of deuterated chloroform. The reactants were dissolved and mixed thoroughly, then transferred to an NMR tube for NMR analysis. The final NMR yield of the reaction was found to be 100%.

[0092] Figure 9 The image shows the 1H NMR spectrum of the target product N,N-diborane-p-fluorophenylethylamine obtained in Example 14. Figure 10 The image shows the carbon NMR spectrum of the target product obtained in Example 14. Figure 9 and Figure 10 It can be seen that the product has the correct structure.

[0093] 1 H NMR (400 MHz, CDCl3) δ 7.27 (t, J = 6.2 Hz, 2H), 6.91 (t, J = 8.1 Hz,2H), 4.17 (s, 2H), 1.22 (d, J = 19.0 Hz, 24H). 13 C NMR (101 MHz, CDCl3) δ 162.74(s), 160.32 (s), 138.84 (d, J = 3.1 Hz), 129.18 (d, J = 7.9 Hz), 114.53 (s), 114.32 (s), 82.31 (s), 46.56 (s), 24.45 (s).

[0094] Example 15

[0095] Add p-chlorobenzonitrile (55 mg, 0.4 mmol), HBpin (175 μL, 1.2 mmol), and Mo(CO)6 (5.3 mg, 5 mol%) to a 5 mL reaction tube and heat at 80 °C for 8 hours. Post-reaction processing: Add tetraethylsilane (75 μL, 0.4 mmol) directly to the reaction solution as an internal standard, then add 0.6 mL of deuterated chloroform to dissolve and mix the reactants thoroughly. Transfer the solution to an NMR tube for NMR analysis. The final NMR yield of this reaction was 97%.

[0096] Figure 11 The image shows the 1H NMR spectrum of the target product N,N-diborane-p-chlorophenethylamine obtained in Example 15. Figure 12 The image shows the carbon NMR spectrum of the target product obtained in Example 15. Figure 11 and Figure 12 It can be seen that the product has the correct structure.

[0097] 1 H NMR (400 MHz, CDCl3) δ 7.22 (dd, J = 17.5, 7.7 Hz, 4H), 4.18 (s, 2H), 1.21 (d, J = 19.7 Hz, 24H). 13 C NMR (101 MHz, CDCl3) δ 141.59 (s), 131.77 (s), 128.95 (s), 127.88 (s), 82.36 (s), 46.63 (s), 24.46 (s).

[0098] Example 16

[0099] p-Bromobenzonitrile (73 mg, 0.4 mmol), HBpin (175 μL, 1.2 mmol), and Mo(CO)6 (5.3 mg, 5 mol%) were added to a 5 mL reaction tube, and the mixture was heated at 80 °C for 8 hours. Post-reaction processing: Tetraethylsilane (75 μL, 0.4 mmol) was added directly to the reaction solution as an internal standard, followed by 0.6 mL of deuterated chloroform. The reactants were dissolved and mixed thoroughly, then transferred to an NMR tube for NMR analysis. The final NMR yield of the reaction was 99.5%.

[0100] Figure 13 The image shows the 1H NMR spectrum of the target product N,N-diborane-p-bromophenylethylamine obtained in Example 16. Figure 14 The image shows the carbon NMR spectrum of the target product obtained in Example 16. Figure 13 and Figure 14 It can be seen that the product has the correct structure.

[0101] 1 H NMR (400 MHz, CDCl3) δ 7.35 (d, J = 7.7 Hz, 2H), 7.18 (d, J = 7.7 Hz, 2H), 4.16 (s, 2H), 1.25 (s, 24H). 13 C NMR (101 MHz, CDCl3) δ 142.07 (s), 130.80 (s), 129.30 (s), 119.81 (s), 82.31 (s), 46.63 (s), 24.45 (d, J = 3.6 Hz).

[0102] Example 17

[0103] To a 5 mL reaction tube, p-iodobenzonitrile (92 mg, 0.4 mmol), HBpin (175 μL, 1.2 mmol), and Mo(CO)₆ (5.3 mg, 5 mol%) were added, and the mixture was heated at 80 °C for 8 hours. Post-reaction processing: Tetraethylsilane (75 μL, 0.4 mmol) was added directly to the reaction solution as an internal standard, followed by 0.6 mL of deuterated chloroform. The reactants were dissolved and mixed thoroughly, then transferred to an NMR tube for NMR analysis. The final NMR yield of the reaction was 92%.

[0104] Figure 15 The image shows the 1H NMR spectrum of the target product N,N-diborane-p-iodophenethylamine obtained in Example 17. Figure 16 The image shows the carbon NMR spectrum of the target product obtained in Example 17. Figure 15 and Figure 16 It can be seen that the product has the correct structure.

[0105] 1 H NMR (400 MHz, CDCl3) δ 7.58 (dd, J = 21.0, 7.5 Hz, 2H), 7.07 (t, J =11.2 Hz, 2H), 4.18 (d, J = 22.9 Hz, 2H), 1.21 (d, J = 20.1 Hz, 24H). 13 C NMR (101MHz, CDCl3) δ 142.75 (s), 136.84 (s), 129.62 (s), 91.32 (s), 82.37 (s), 46.75(s), 24.51(d,J = 3.9 Hz).

[0106] In conjunction with Examples 14-17, this reaction system exhibits good functional group compatibility with halogens, and can yield the corresponding hydroboration products with a yield of over 90% for F, Cl, Br, and I.

[0107] Example 18

[0108] Add 53 μL (0.4 mmol) of p-trifluoromethylbenzonitrile, 175 μL (1.2 mmol) of HBpin, and 5.3 mg (5 mol%) of Mo(CO)6 to a 5 mL reaction tube and heat at 80 °C for 8 hours. Post-reaction processing: Add 75 μL (0.4 mmol) of tetraethylsilane as an internal standard directly to the reaction solution, followed by 0.6 mL of deuterated chloroform. Dissolve and mix the reactants thoroughly, transfer the solution to an NMR tube, and perform NMR analysis. The final NMR yield of the reaction was found to be 100%.

[0109] Figure 17 The image shows the 1H NMR spectrum of the target product N,N-diborane-p-trifluoromethylphenethylamine obtained in Example 18. Figure 18 The image shows the carbon NMR spectrum of the target product obtained in Example 18. Figure 17 and Figure 18 It can be seen that the product has the correct structure.

[0110] 1 H NMR (400 MHz, CDCl3) δ 7.50 (d, J = 7.7 Hz, 2H), 7.41 (d, J = 7.8 Hz, 2H), 4.28 (s, 2H), 1.19 (s, 25H). 13 C NMR (101 MHz, CDCl3) δ 147.12 (s), 127.63 (s), 124.74 (d, J = 3.8 Hz), 82.46 (s), 46.96 (s), 24.43 (d, J = 5.0 Hz).

[0111] Example 19

[0112] p-Methoxybenzonitrile (54 mg, 0.4 mmol), HBpin (175 μL, 1.2 mmol), and Mo(CO)6 (5.3 mg, 5 mol%) were added to a 5 mL reaction tube, and the mixture was heated at 80 °C for 8 hours. Post-reaction processing: Tetraethylsilane (75 μL, 0.4 mmol) was added directly to the reaction solution as an internal standard, followed by 0.6 mL of deuterated chloroform. The reactants were dissolved and mixed thoroughly, then transferred to an NMR tube for NMR analysis. The final NMR yield of the reaction was 99.5%.

[0113] Figure 19 The image shows the 1H NMR spectrum of the target product N,N-diborane-p-methoxyphenethylamine obtained in Example 19. Figure 20 The image shows the carbon NMR spectrum of the target product obtained in Example 19. Figure 19 and Figure 20 It can be seen that the product has the correct structure.

[0114] 1 H NMR (400 MHz, CDCl3) δ 7.01 (d, J = 7.9 Hz, 2H), 6.53 (d, J = 7.9 Hz,2H), 3.92 (s, 2H), 3.50 (s, 3H), 0.98 (d, J = 10.6 Hz, 24H). 13 C NMR (101 MHz, CDCl3) δ 158.05 (s), 135.32 (s), 128.76 (s), 113.06 (s), 82.07 (s), 54.87 (s), 46.50 (s), 24.42 (s).

[0115] Example 20

[0116] p-tert-butylbenzonitrile (64 mg, 0.4 mmol), HBpin (175 μL, 1.2 mmol), and Mo(CO)₆ (5.3 mg, 5 mol%) were added to a 5 mL reaction tube, and the mixture was heated at 80 °C for 8 hours. Post-reaction processing: Tetraethylsilane (75 μL, 0.4 mmol) was added directly to the reaction solution as an internal standard, followed by 0.6 mL of deuterated chloroform. The reactants were dissolved and mixed thoroughly, then transferred to an NMR tube for NMR analysis. The final NMR yield of the reaction was 95%.

[0117] Figure 21 The image shows the 1H NMR spectrum of the target product N,N-diborane-p-tert-butylphenethylamine obtained in Example 20. Figure 22The image shows the carbon NMR spectrum of the target product obtained in Example 19. Figure 21 and Figure 22 It can be seen that the product has the correct structure.

[0118] 1 H NMR (400 MHz, CDCl3) δ 7.24 (s, 4H), 4.19 (s, 2H), 1.29 (s, 12H), 1.20 (d, J = 10.5 Hz, 25H). 13 C NMR (101 MHz, CDCl3) δ 148.70 (s), 140.10 (s), 127.38 (s), 124.58 (s), 83.05 (d, J = 17.4 Hz), 82.17 (s), 46.85 (s), 34.29(s), 31.42 (s), 24.86 (s), 24.51 (d, J = 2.3 Hz).

[0119] Example 21

[0120] To a 5 mL reaction tube, p-fluorophenylacetonitrile (54 mg, 0.4 mmol), HBpin (175 μL, 1.2 mmol), and Mo(CO)₆ (5.3 mg, 5 mol%) were added, and the mixture was heated at 80 °C for 8 hours. Post-reaction processing: Tetraethylsilane (75 μL, 0.4 mmol) was added directly to the reaction solution as an internal standard, followed by 0.6 mL of deuterated chloroform. The reactants were dissolved and mixed thoroughly, then transferred to an NMR tube for NMR analysis. The final NMR yield of the reaction was 84%.

[0121] Figure 23 The image shows the 1H NMR spectrum of the target product N,N-diborane-p-fluorophenylamine obtained in Example 21. Figure 24 The image shows the carbon NMR spectrum of the target product obtained in Example 21. Figure 23 and Figure 24 It can be seen that the product has the correct structure.

[0122] 1 H NMR (400 MHz, CDCl3) δ 7.11 (s, 2H), 6.91 (t, J = 8.5 Hz, 2H), 3.27(t, J = 6.5 Hz, 2H), 2.67 (t, J = 6.4 Hz, 2H), 1.20 (d, J= 23.8 Hz, 23H). 13 C NMR (101 MHz, CDCl3) δ 162.57 (s), 160.15 (s), 130.58 (d, J = 7.7 Hz), 115.37 –114.73 (m), 114.55 (s), 82.95 (s), 82.00 (s), 45.09 (s), 38.43 (s), 24.42 (d, J = 9.2 Hz).

[0123] Example 22

[0124] Terephthalonitrile (52 mg, 0.4 mmol), HBpin (350 μL, 2.4 mmol), and Mo(CO)₆ (10.6 mg, 10 mol%) were added to a 5 mL reaction tube, and the mixture was heated at 80 °C for 8 hours. Post-reaction processing: Tetraethylsilane (75 μL, 0.4 mmol) was added directly to the reaction solution as an internal standard, followed by 0.6 mL of deuterated chloroform. The reactants were dissolved and mixed thoroughly, then transferred to an NMR tube for NMR analysis. The final NMR yield of the reaction was 87.5%.

[0125] Figure 25 The image shows the 1H NMR spectrum of the target product N,N-diborane-p-phenylenediamine obtained in Example 22. Figure 26 The image shows the carbon NMR spectrum of the target product obtained in Example 22. Figure 25 and Figure 26 It can be seen that the product has the correct structure.

[0126] 1 H NMR (400 MHz, CDCl3) δ 7.08 (s, 4H), 4.09 (s, 3H), 1.10 (s, 41H). 13 C NMR (101 MHz, CDCl3) δ 140.66 (s), 126.84 (s), 82.88 (s), 82.81 – 81.66(m), 46.84 (s), 24.44 (d, J = 6.3 Hz), 7.35 (s), 2.87 (s).

[0127] Example 23

[0128] 2-Cyanofuran (35 μL, 0.4 mmol), HBpin (175 μL, 1.2 mmol), and Mo(CO)6 (5.3 mg, 5 mol%) were added to a 5 mL reaction tube, and the mixture was heated at 80 °C for 8 hours. Post-reaction processing: Tetraethylsilane (75 μL, 0.4 mmol) was added directly to the reaction solution as an internal standard, followed by 0.6 mL of deuterated chloroform. The reactants were dissolved and mixed thoroughly, then transferred to an NMR tube for NMR analysis. The final NMR yield of the reaction was 88%.

[0129] Figure 27 The image shows the 1H NMR spectrum of the target product N,N-diborane-2-furanethylamine obtained in Example 23. Figure 28 The image shows the carbon NMR spectrum of the target product obtained in Example 23. Figure 27 and Figure 28 It can be seen that the product has the correct structure.

[0130] 1 H NMR (400 MHz, CDCl3) δ 7.24 (s, 1H), 6.22 (s, 1H), 6.04 (s, 1H), 4.19 (s, 2H), 1.21 (s, 23H). 13 C NMR (101 MHz, CDCl3) δ 156.45 (s), 140.65 (s), 109.84 (s), 105.04 (s), 82.28 (s), 40.57 (s), 24.78 (s), 24.41 (d, J = 7.7 Hz).

[0131] Example 24

[0132] 2-Cyanothiophene (37 μL, 0.4 mmol), HBpin (175 μL, 1.2 mmol), and Mo(CO)6 (5.3 mg, 5 mol%) were added to a 5 mL reaction tube, and the mixture was heated at 80 °C for 8 hours. Post-reaction processing: Tetraethylsilane (75 μL, 0.4 mmol) was added directly to the reaction solution as an internal standard, followed by deuterated chloroform. The reactants were dissolved and mixed thoroughly, then transferred to an NMR tube for NMR analysis. The final NMR yield of the reaction was found to be 100%.

[0133] Figure 29 The image shows the 1H NMR spectrum of the target product N,N-diborane-2-thiopheneethylamine obtained in Example 24. Figure 30 The image shows the carbon NMR spectrum of the target product obtained in Example 24. Figure 29 and Figure 30 It can be seen that the product has the correct structure.

[0134] 1 H NMR (400 MHz, CDCl3) δ 7.12 – 7.03 (m, 1H), 6.90 (s, 1H), 6.85 (d, J = 1.4 Hz, 1H), 4.36 (s, 2H), 1.22 (s, 25H). 13 C NMR (101 MHz, CDCl3) δ 146.72 (s), 126.13 (s), 124.53 (s), 123.54 (s), 82.42 (s), 42.09 (s), 24.50 (s).

[0135] Examples 23 and 24 demonstrate that this reaction system exhibits good compatibility with aromatic heterocyclic compounds such as furan and thiophene.

[0136] Example 25

[0137] Cyclohexanonitrile (47 μL, 0.4 mmol), HBpin (175 μL, 1.2 mmol), and Mo(CO)₆ (5.3 mg, 5 mol%) were added to a 5 mL reaction tube, and the mixture was heated at 80 °C for 8 hours. Post-reaction processing: Tetraethylsilane (75 μL, 0.4 mmol) was added directly to the reaction solution as an internal standard, followed by deuterated chloroform. The reactants were dissolved and mixed thoroughly, then transferred to an NMR tube for NMR analysis. The final NMR yield of the reaction was 97%.

[0138] Figure 31 The image shows the 1H NMR spectrum of the target product N,N-diboranecyclohexylethylamine obtained in Example 25. Figure 32 The image shows the carbon NMR spectrum of the target product obtained in Example 25. Figure 31 and Figure 32 It can be seen that the product has the correct structure.

[0139] 1 H NMR (400 MHz, CDCl3) δ 2.87 (d, J = 6.5 Hz, 2H), 1.66 (t, J = 14.4 Hz, 5H), 1.24 (d, J = 21.6 Hz, 31H). 13C NMR (101 MHz, CDCl3) δ 81.80 (s), 49.57 (s), 40.44 (s), 30.46 (s), 26.70 (s), 26.08 (s), 24.75 (s), 24.38 (d, J = 7.5 Hz).

[0140] Example 26

[0141] Acetonitrile (21 μL, 0.4 mmol), HBpin (175 μL, 1.2 mmol), and Mo(CO)₆ (5.3 mg, 5 mol%) were added to a 5 mL reaction tube, and the mixture was heated at 80 °C for 8 hours. Post-reaction processing: Tetraethylsilane (75 μL, 0.4 mmol) was added directly to the reaction solution as an internal standard, followed by deuterated chloroform. The reactants were dissolved and mixed thoroughly, then transferred to an NMR tube for NMR analysis. The final NMR yield of the reaction was 99.2%.

[0142] Figure 33 The image shows the 1H NMR spectrum of the target product N,N-diborane ethylamine obtained in Example 26. Figure 34 The image shows the carbon NMR spectrum of the target product obtained in Example 26. Figure 33 and Figure 34 It can be seen that the product has the correct structure.

[0143] 1 H NMR (400 MHz, CDCl3) δ 3.06 (d, J = 6.6 Hz, 2H), 1.22 (s, 24H), 1.02(t, J = 6.4 Hz, 3H). 13 C NMR (101 MHz, CDCl3) δ 81.81 (s), 38.42 (s), 24.39 (d, J =4.5 Hz), 18.51 (s).

[0144] Examples 21, 25, and 26 demonstrate that this reaction system is also applicable to fatty nitrile compounds.

Claims

1. A method for catalyzing the hydroboration reaction of nitrile compounds, characterized in that: Using nitrile compounds as substrates, molybdenum hexacarbonyl as catalyst, and pinacolborane as hydrogen source, the hydroboration reaction was carried out at 78-82℃ for 7.5-8.5 h; the molar ratio of molybdenum hexacarbonyl to nitrile compounds was 1-2:20, and the molar ratio of nitrile compounds to pinacolborane was 1:3-6.

2. The method for catalyzing the hydroboration reaction of nitrile compounds according to claim 1, characterized in that: The nitrile compound is one of the following: p-methylbenzonitrile, benzonitrile, m-methylbenzonitrile, o-methylbenzonitrile, p-fluorobenzonitrile, p-chlorobenzonitrile, p-bromobenzonitrile, p-iodobenzonitrile, p-trifluoromethylbenzonitrile, p-methoxybenzonitrile, p-tert-butylbenzonitrile, p-fluorophenylacetonitrile, p-phthalonitrile, 2-cyanofuran, 2-cyanothiophene, cyclohexylbenzonitrile, and acetonitrile.

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