Z-type olefin synthesis method using polyoxometalate molybdate as photocatalyst
Through the polymetal oxygen molybdate [N(C4H9)4]2[Mo6O19] photocatalyst, direct phosphonation reaction under no transition metal conditions was achieved, and the stereoselectivity and thermodynamic stability problems in the preparation of Z-alkenylphosphine oxide compounds were solved, and a series of Z-alkenylphosphine oxide compounds were synthesized.
Patent Information
- Application Number
- CN202510773261.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-11
- Publication Date
- 2025-08-26
AI Technical Summary
The existing preparation methods for Z-alkenylphosphine oxy compounds have problems such as low efficiency, multi-step operation, poor chemical selectivity and stereoselectivity, and the thermodynamic instability of the Z-alkenyl phosphine oxy compounds, which are prone to isomerization.
The polymetal oxygen molybdate [N(C4H9)4]2[Mo6O19] was used as the photocatalyst, and the direct phosphonation reaction was carried out under no transition metal conditions by irradiating Z-type olefins by visible light.
Under mild reaction conditions, high chemical selectivity and stereoselectivity were achieved, and a series of Z-alkenyl phosphine oxide compounds were synthesized, with good yield and catalyst stability, a wide range of application, simple operation and environmentally friendly.
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Figure CN120535552A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of green organic synthesis, and specifically relates to a polymetallic oxygen cluster molybdate [N(C4H9)4]2[Mo6O 19 ] is a photocatalyst for the synthesis of Z-olefins, mainly used for the synthesis of Z-alkenylphosphine oxides. Background Art
[0002] Z-alkenylphosphine oxides, a representative example, have a wide range of synthetic applications in chemical synthesis. Existing methods for preparing Z-alkenylphosphine oxides suffer from the use of transition metal catalysts (such as cobalt / ruthenium complexes), multi-step procedures, low chemoselectivity and stereoselectivity, or limited substrate scope. Synthesizing alkenylphosphine oxides via direct radical addition reactions of alkynes is a simple and atom-economical method. However, controlling the Z selectivity of alkenes in radical addition reactions remains a significant challenge, centered on three key aspects: 1) precise control of stereoselectivity within the system, which requires a balance between steric hindrance and electronic effects; 2) reaction conditions limit their application, necessitating the development of mild and efficient catalytic systems; and 3) the thermodynamic instability of Z-alkenylphosphine oxides, which can easily lead to isomerization. In recent years, photocatalysis has gained widespread application as a green, atom-economical method for the direct phosphonylation of alkynes via free radical processes, but few reports have been published on the synthesis of Z-alkenylphosphine oxides.
[0003] Polyoxometallic molybdate is a metal oxide cluster with unique photoinduced charge transfer and redox properties, which is thermally stable and oxidatively stable. 19 ] as a photocatalyst to achieve the phosphonylation of compounds containing C(sp2)-H bonds and thiol compounds, indicating that it has the ability of oxidative dehydrogenation under visible light irradiation and has the advantages of being green, efficient and recyclable. Summary of the Invention
[0004] (1) Technical issues to be solved
[0005] The present invention provides a method for synthesizing Z-olefins using polymetallic oxoclusate as a photocatalyst, so as to solve the technical problems of regulating the addition site of phosphine radicals and alkynes and controlling stereochemistry in the previous phosphonylation reaction.
[0006] (2) Technical solution
[0007] In order to solve the above technical problems, the present invention proposes a Z-olefin synthesis method using polymetallic oxo cluster molybdate as a photocatalyst. The Z-olefin synthesis method comprises the following steps: using an aryl alkyne compound as a substrate, a phosphorus-containing compound as a phosphorus source, and tert-butyl hydroperoxide as an oxidant; and adding a photocatalyst N(C4H9)4]2[Mo6O 19 ], Z-olefins were directly synthesized in an argon environment.
[0008] Furthermore, the photocatalyst N(C4H9)4]2[Mo6O 19 ] is prepared by: (NH4)6Mo7O 24 4H2O and [N(C4H9)4]Br were dissolved in water respectively, and a turbid solution containing a white precipitate was obtained after stirring. Under stirring, hydrochloric acid was added dropwise to the turbid solution, and the white precipitate turned into a yellow precipitate. The stirring was continued, and the yellow precipitate was obtained after filtration. The yellow precipitate was dried to obtain the photocatalyst N(C4H9)4]2[Mo6O 19 ].
[0009] Furthermore, the photocatalyst N(C4H9)4]2[Mo6O 19 The specific preparation method is as follows: 5.0g 4mmol (NH4) 6Mo7O 24 4H2O and 4.0g 12mmol [N(C4H9)4]Br were dissolved in 100mL water respectively and stirred for 0.5h to obtain a turbid solution containing a white precipitate. Under stirring, hydrochloric acid was added dropwise to the turbid solution to control the pH value of the turbid solution at 3.0-4.0. The white precipitate turned into a yellow precipitate. Stirring was continued for 3h. After filtration, a yellow precipitate was obtained. The yellow precipitate was placed in a vacuum drying oven and dried at 50℃ for 36h to obtain the photocatalyst N(C4H9)4]2[Mo6O 19 ].
[0010] Furthermore, the aromatic alkyne compound is at least one of phenylacetylene, 4-tert-butylphenylacetylene, 3-ethynylthiophene, 2-alkynyl-naphthalene, 1-ethynyl-3-fluorobenzene, 2-ethynyltoluene, 3'-bromophenylacetylene, 4-isopropylphenylacetylene, 3-ethynyltoluene, (4-bromophenyl)acetylene, 1-ethynyl-4-methylbenzene, 1-ethynyl-4-fluorobenzene, 4-ethynyl-α,α,α-trifluorotoluene, and 1-chloro-4-ethynylbenzene; and the phosphorus-containing compound is at least one of diphenylphosphine oxide, di(4-methylphenyl)phosphine oxide, di(4-methoxyphenyl)phosphine oxide, di(4-chlorophenyl)phosphine oxide, 2,2'-bis-(2-naphthyl)phosphine oxide, di(thiophene-2-yl)phosphite, phenyl(benzyl)phosphine oxide, butyl(phenyl)phosphine oxide, and cyclohexyl(phenyl)phosphine oxide.
[0011] Furthermore, the Z-olefin synthesis method is specifically as follows:
[0012] S1. Phosphorus-containing compound, photocatalyst N(C4H9)4]2[Mo6O 19 ] is added to a reaction tube, a magnetic particle is placed in the reaction tube, and an oxygen-free environment is formed in the reaction tube;
[0013] S2. The aromatic alkyne compound and tert-butyl hydroperoxide are injected into the reaction tube, and a solvent is added to the reaction tube. The reaction tube is placed in a photoreactor and subjected to light synthesis reaction at room temperature to obtain a reaction solution.
[0014] S3. Purify the reaction solution to obtain pure Z-olefin.
[0015] Furthermore, in step S1, 0.4 mmol of phosphorus-containing compound and 0.002 mmol of photocatalyst N(C4H9)4]2[Mo6O 19 ] are added to the reaction tube; in step S2, 0.2 mmol of aromatic alkyne compound and 0.4 mmol of tert-butyl hydroperoxide are injected into the reaction tube.
[0016] Furthermore, in step S1, the method for forming an oxygen-free environment is to insert two needles into the rubber stopper of the reaction tube, introduce inert gas into the reaction tube through one needle, and exhaust the air in the reaction tube through the other needle.
[0017] Furthermore, in step S2, the solvent is 1,2-dichloroethane solvent.
[0018] Furthermore, in step S2, the conditions for the light synthesis reaction are: light wavelength 390nm, light intensity 8W.
[0019] Furthermore, in step S3, when the reaction solution is purified, the reaction solution is evenly spread on the surface of a silica gel column and separated by column chromatography to obtain pure Z-olefin.
[0020] (3) Beneficial effects
[0021] The present invention provides a method for synthesizing Z-olefins using polyoxometallic molybdate as a photocatalyst, using Lindquist-type polyoxomolybdate [N(C4H9)4]2[Mo6O 19] As a photocatalyst, it catalyzes P(O)-H compounds to induce phosphine free radicals, realizes the addition of phosphine free radicals to aromatic alkyne compounds, and uses tert-butyl hydroperoxide as an oxidant to provide a variety of Z-type alkenes with medium yields. The present invention can realize the direct phosphonylation reaction of aromatic alkyne compounds under mild conditions without transition metals, and can synthesize a series of Z-alkenyl phosphine oxide compounds. The catalyst used has good stability and reusability, and also shows satisfactory photocatalytic activity under sunlight irradiation. The reaction method has the advantages of mild reaction conditions and easy separation and purification, environmental friendliness, high chemical selectivity and stereoselectivity, simple operation, wide range of application, good yield, etc. The gram-level reaction shows the potential application value of the reaction method. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 The product (Z)-(styryl)diphenylphosphine oxide of Example 1 1 H-NMR spectrum;
[0023] Figure 2 The product (Z)-(styryl)diphenylphosphine oxide of Example 1 31 P-NMR spectrum;
[0024] Figure 3 The product (Z)-(styryl)diphenylphosphine oxide of Example 1 13 C-NMR spectrum;
[0025] Figure 4 The product (Z)-(4-methylphenyl)diphenylphosphine oxide of Example 2 1 H-NMR spectrum;
[0026] Figure 5 The product (Z)-(4-methylphenyl)diphenylphosphine oxide of Example 2 31 P-NMR spectrum;
[0027] Figure 6 The product (Z)-(4-methylphenyl)diphenylphosphine oxide of Example 2 13 C-NMR spectrum;
[0028] Figure 7 The product (Z)-bis(4-chlorophenyl)(styryl)phosphine oxide of Example 3 1 H-NMR spectrum;
[0029] Figure 8 The product (Z)-bis(4-chlorophenyl)(styryl)phosphine oxide of Example 3 31 P-NMR spectrum;
[0030] Figure 9 The product (Z)-bis(4-chlorophenyl)(styryl)phosphine oxide of Example 3 13 C-NMR spectrum. DETAILED DESCRIPTION
[0031] In order to make the purpose, content and advantages of the present invention more clear, the specific implementation methods of the present invention are further described in detail below with reference to the accompanying drawings and examples.
[0032] Example 1
[0033] This embodiment provides a method for synthesizing (Z)-(styryl)diphenylphosphine oxide, comprising the following steps:
[0034] S1. 0.4mmol diphenylphosphine and 0.002mmol photocatalyst [N(C4H9)4]2[Mo6O 19 ] to a 10 mL reaction tube and place a magnetic rod in the tube. Insert two needles into the stopper of the tube. Inert gas is introduced into the tube through one needle and the air is exhausted through the other needle. An argon balloon is then inserted.
[0035] S2. Inject 0.2 mmol of phenylacetylene and 0.4 mmol of tert-butyl hydroperoxide into a reaction tube using a syringe. Add 2 mL of ultra-dry 1,2-dichloroethane solvent to the reaction tube. Place the reaction tube in a photoreactor with illumination at a wavelength of 390 nm and an intensity of 8 W. React at room temperature for 12 hours to obtain a reaction solution.
[0036] S3. The reaction solution was evenly spread on the surface of a silica gel column, and separated and purified by column chromatography using petroleum ether / ethyl acetate (1:1) as eluent to obtain pure (Z)-(styryl)diphenylphosphine oxide.
[0037] The (Z)-(styryl)diphenylphosphine oxide obtained by the above method has a yield of 84% and a Z:E ratio of 97:3. The characterization data of the obtained product are: 1 HNMR(600MHz,Chloroform-d)δ7.76–7.72(m,4H),7.69(dd,J=6.7,2.9Hz,2H),7.54(dd,J=40.3,14.1Hz,1 H),7.43–7.40(m,2H),7.36(ddd,J=8.5,6.6,2.9Hz,4H),7.19–7.16(m,3H),6.32(dd,J=19.4,14.1Hz,1H). 13C NMR (151MHz, Chloroform-d) δ131.43,131.41,130.97,130.90,130.20,129.35,128.47,128.39,127.98. 31 P NMR (243MHz, CDCl3) δ 20.04. The product (Z)-(styryl) diphenylphosphine oxide 1 H-NMR spectrum, 13 C-NMR spectra and 13 The P-NMR spectra are as follows Figures 1 to 3 shown.
[0038] Example 2
[0039] This embodiment provides a method for synthesizing (Z)-(4-methylphenyl)diphenylphosphine oxide, comprising the following steps:
[0040] S1. 0.4mmol diphenylphosphine and 0.002mmol photocatalyst [N(C4H9)4]2[Mo6O 19 ] to a 10 mL reaction tube and place a magnetic rod in the tube. Insert two needles into the stopper of the tube. Inert gas is introduced into the tube through one needle and the air is exhausted through the other needle. An argon balloon is then inserted.
[0041] S2. Inject 0.2 mmol of p-methylphenylacetylene and 0.4 mmol of tert-butyl hydroperoxide into a reaction tube using a syringe. Add 2 mL of ultra-dry 1,2-dichloroethane solvent to the reaction tube. Place the reaction tube in a photoreactor with illumination at a wavelength of 390 nm and an intensity of 8 W. React at room temperature for 12 hours to obtain a reaction solution.
[0042] S3. The reaction solution was evenly spread on the surface of a silica gel column, and separated and purified by column chromatography using petroleum ether / ethyl acetate (1:1) as eluent to obtain pure (Z)-(4-methylphenyl)diphenylphosphine oxide.
[0043] The (Z)-(4-methylphenyl)diphenylphosphine oxide obtained by the above method has a yield of 73% and a Z:E ratio of 95:5. The characterization data of the obtained product are: 1H NMR(600MHz,Chloroform-d)δ7.74(d,J=12.0Hz,4H),7.61(d,J=6.2Hz,2H),7.48(dd,J=40.6,14.1Hz,2H),7.4 3–7.39(m,2H),7.36(td,J=7.3,2.9Hz,4H),6.98(d,J=7.9Hz,2H),6.22(dd,J=19.8,14.1Hz,1H),2.23(s,2H). 13 C NMR(151MHz,Chloroform-d)δ150.09,139.68,134.42,133.72,131.39,131. 37,130.98,130.92,130.38,128.75,128.49,128.41,120.51,119.86,21.35. 31 P NMR (243MHz, CDCl3) δ 20.57. The product (Z)-(4-methylphenyl)diphenylphosphine oxide 1 H-NMR spectrum, 13 C-NMR spectra and 13 The P-NMR spectra are as follows Figures 4-6 shown.
[0044] Example 3
[0045] This embodiment provides a method for synthesizing (Z)-bis(4-chlorophenyl)(styryl)phosphine oxide, comprising the following steps:
[0046] S1. 0.4mmol bis(4-chlorophenyl)phosphine oxide and 0.002mmol photocatalyst [N(C4H9)4]2[Mo6O 19 ] to a 10 mL reaction tube and place a magnetic rod in the tube. Insert two needles into the stopper of the tube. Inert gas is introduced into the tube through one needle and the air is exhausted through the other needle. An argon balloon is then inserted.
[0047] S2. Inject 0.2 mmol of phenylacetylene and 0.4 mmol of tert-butyl hydroperoxide into a reaction tube using a syringe. Add 2 mL of ultra-dry 1,2-dichloroethane solvent to the reaction tube. Place the reaction tube in a photoreactor with illumination at a wavelength of 390 nm and an intensity of 8 W. React at room temperature for 12 hours to obtain a reaction solution.
[0048] S3. The reaction solution was evenly spread on the surface of a silica gel column, and separated and purified by column chromatography using petroleum ether / ethyl acetate (1:1) as eluent to obtain pure (Z)-bis(4-chlorophenyl)(styryl)phosphine oxide.
[0049] The (Z)-bis(4-chlorophenyl)(styryl)phosphine oxide obtained by the above method has a yield of 54% and a Z:E ratio of 96:4. The characterization data of the obtained product are: 1 H NMR(600MHz,Chloroform-d)δ7.66–7.53(m,6H),7.34(dq,J=8.9,2.3Hz,3H),7.22–7.17(m,3H),6.26(dd,J=20.0,14.0Hz,1H). 13 C NMR(151MHz,Chloroform-d)δ151.07,138.24,138.21,134.61,134.56,132.39,1 32.28,132.21,131.68,130.07,129.74,128.94,128.86,128.13,121.09,120.42. 31 PNMR (243MHz, Chloroform-d) δ18.71. The product (Z)-bis(4-chlorophenyl)(styryl)phosphine oxide 1 H-NMR spectrum, 13 C-NMR spectra and 13 The P-NMR spectra are as follows Figures 7-9 shown.
[0050] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.
Claims
1. A method for synthesizing Z-olefins using polyoxometallic molybdate as a photocatalyst, characterized in that: The Z-olefin synthesis method comprises the following steps: using an aryl alkyne compound as a substrate, a phosphorus-containing compound as a phosphorus source, and tert-butyl hydroperoxide as an oxidant, and adding a photocatalyst N(C4H9)4]2[Mo6O 19 ], Z-olefins were directly synthesized in an argon environment.
2. The method for synthesizing Z-olefins using polyoxometalate molybdate as a photocatalyst according to claim 1, wherein: The photocatalyst N(C4H9)4]2[Mo6O 19 ] is prepared by: (NH4)6Mo7O 24 4H2O and [N(C4H9)4]Br were dissolved in water respectively, and a turbid solution containing a white precipitate was obtained after stirring. Under stirring, hydrochloric acid was added dropwise to the turbid solution, and the white precipitate turned into a yellow precipitate. The stirring was continued, and the yellow precipitate was obtained after filtration. The yellow precipitate was dried to obtain the photocatalyst N(C4H9)4]2[Mo6O 19 ].
3. The method for synthesizing Z-olefins using polyoxometalate molybdate as a photocatalyst according to claim 2, wherein: The photocatalyst N(C4H9)4]2[Mo6O 19 The specific preparation method is as follows: 5.0g 4mmol (NH4) 6Mo7O 24 4H2O and 4.0g 12mmol [N(C4H9)4]Br were dissolved in 100mL water respectively and stirred for 0.5h to obtain a turbid solution containing a white precipitate. Under stirring, hydrochloric acid was added dropwise to the turbid solution to control the pH value of the turbid solution at 3.0-4.
0. The white precipitate turned into a yellow precipitate. Stirring was continued for 3h. After filtration, a yellow precipitate was obtained. The yellow precipitate was placed in a vacuum drying oven and dried at 50℃ for 36h to obtain the photocatalyst N(C4H9)4]2[Mo6O 19 ].
4. The method for synthesizing Z-olefins using polyoxometalate molybdate as a photocatalyst according to claim 1, wherein: The aromatic alkyne compound is at least one of phenylacetylene, 4-tert-butylphenylacetylene, 3-ethynylthiophene, 2-alkynyl-naphthalene, 1-ethynyl-3-fluorobenzene, 2-ethynyltoluene, 3'-bromophenylacetylene, 4-isopropylphenylacetylene, 3-ethynyltoluene, (4-bromophenyl)acetylene, 1-ethynyl-4-methylbenzene, 1-ethynyl-4-fluorobenzene, 4-ethynyl-α,α,α-trifluorotoluene, and 1-chloro-4-ethynylbenzene; and the phosphorus-containing compound is at least one of diphenylphosphine oxide, di(4-methylphenyl)phosphine oxide, di(4-methoxyphenyl)phosphine oxide, di(4-chlorophenyl)phosphine oxide, 2,2'-bis-(2-naphthyl)phosphine oxide, di(thiophene-2-yl)phosphite, phenyl(benzyl)phosphine oxide, butyl(phenyl)phosphine oxide, and cyclohexyl(phenyl)phosphine oxide.
5. The method for synthesizing Z-olefins using polyoxometalate molybdate as a photocatalyst according to claim 1, wherein: The Z-olefin synthesis method is specifically as follows: S1. Phosphorus-containing compound, photocatalyst N(C4H9)4]2[Mo6O 19 ] is added to a reaction tube, a magnetic particle is placed in the reaction tube, and an oxygen-free environment is formed in the reaction tube; S2. The aromatic alkyne compound and tert-butyl hydroperoxide are injected into the reaction tube, and a solvent is added to the reaction tube. The reaction tube is placed in a photoreactor and subjected to light synthesis reaction at room temperature to obtain a reaction solution. S3. Purify the reaction solution to obtain pure Z-olefin.
6. The method for synthesizing Z-olefins using polyoxometalate molybdate as a photocatalyst according to claim 5, wherein: In step S1, 0.4 mmol of phosphorus-containing compound and 0.002 mmol of photocatalyst N(C4H9)4]2[Mo6O 19 ] are added to the reaction tube; in step S2, 0.2 mmol of aromatic alkyne compound and 0.4 mmol of tert-butyl hydroperoxide are injected into the reaction tube.
7. The method for synthesizing Z-olefins using polyoxometalate molybdate as a photocatalyst according to claim 5, wherein: In step S1, the method for forming an oxygen-free environment is to insert two needles into the rubber stopper of the reaction tube, introduce inert gas into the reaction tube through one needle, and exhaust the air in the reaction tube through the other needle.
8. The method for synthesizing Z-olefins using polyoxometalate molybdate as a photocatalyst according to claim 5, wherein: In step S2, the solvent is 1,2-dichloroethane solvent.
9. The method for synthesizing Z-olefins using polyoxometalate molybdate as a photocatalyst according to claim 5, wherein: In step S2, the conditions for the light synthesis reaction are: light wavelength 390nm, light intensity 8W.
10. The method for synthesizing Z-olefins using polyoxometalate molybdate as a photocatalyst according to claim 5, wherein: In step S3, when the reaction solution is purified, the reaction solution is evenly spread on the surface of a silica gel column and separated by column chromatography to obtain pure Z-olefin.