A photoinduced phosphination process for polyfluoroaromatics

Abstract

The present invention discloses a photoinduced phosphination process for polyfluoroaromatic hydrocarbons. The synthesis method of this process is as follows: 1) polyfluoroaromatic hydrocarbon compounds, diphenylphosphine, a photocatalyst, and a solvent are placed in a reaction vessel under nitrogen conditions and reacted under blue light irradiation to obtain a triarylphosphine compound; 2) the triarylphosphine compound is oxidized in air to obtain the corresponding phosphine oxide compound. The present invention features mild reaction conditions, the absence of heavy metals, the use of low-cost raw materials (including polyfluoroaromatic hydrocarbons and diphenylphosphine), simple operation, and environmental friendliness. The present invention can be widely used in pharmaceutical synthesis and material synthesis in industry and academia, and has high application value.

Description

Technical Field

[0001] The present invention relates to the technical field of organic intermediate synthesis, and in particular to a process for inducing phosphination reaction of polyfluoroaromatic hydrocarbons by a photochemical method. Background Art

[0002] Triarylphosphine compounds are a very important class of ligands, widely used in transition metal-catalyzed coupling reactions. Furthermore, triarylphosphine compounds can be used as catalysts for a variety of organic synthesis reactions, with applications ranging from pharmaceutical chemistry to materials chemistry. Current methods for synthesizing triarylphosphine compounds are as follows:

[0003] Method 1: Using diphenyl (trimethylsilyl) phosphine and aryl chloride as substrates, nickel catalyzes the cross-coupling reaction of CP. In the presence of NiCl2(PPh3)2 as catalyst, t Using BuOK as a base and 1,4-dioxane as a solvent, the reaction was carried out at 90°C for 12 hours to generate triarylphosphine compounds. (Eur. J. Org. Chem. 2014, 6796-6801)

[0004]

[0005] This method uses toxic and expensive metal catalysts and requires strict reaction conditions.

[0006] Method 2: 1,2-bis(diphenylphosphino)ethane and aryl halide t BuOK was used as base and dimethyl sulfoxide as solvent. The reaction was carried out at 115℃ for 6h to generate C(sp 2 )-P bond coupling reaction to generate triarylphosphine compounds. (Chin.J.Org.Chem.2019,39,2930~2935)

[0007]

[0008] This method uses an excess of strong base, has a high reaction temperature, and requires strict reaction conditions.

[0009] Method 3: Diphenylphosphine and aryl halide react in Et3N as a base, [Ir(ppy)2(dtbbpy)]PF6 as a photocatalyst, and acetonitrile or benzene as a solvent. The reaction is carried out under blue light irradiation for 18 hours, and an arylation reaction occurs to form triarylphosphine compounds. (Chem.–Eur.J.2020, 26, 16374-16382)

[0010]

[0011] This method verifies that diphenylphosphine can undergo arylation reaction in a photocatalytic system and can produce diphenylphosphine radicals, but the reaction time is relatively long. Summary of the Invention

[0012] In view of the above problems, the present invention aims to provide a photoinduced phosphination process for polyfluoroaromatic hydrocarbons that is low in cost, simple to operate, does not involve heavy metals, has mild reaction conditions, and is easy to promote in industrial production.

[0013] In order to achieve the above object, the technical solution adopted by the present invention is as follows: a photoinduced phosphination process of polyfluoroaromatic hydrocarbons, the synthesis method of the process is as follows:

[0014]

[0015] Wherein, X is C or N, R is H, trifluoromethyl and C2-C5 ester group; n is the number of substituents F, and n is 2-4.

[0016] The catalyst is a photocatalyst, and the photocatalyst is [Ir(ppy)2(dtbbpy)]PF6 or 4-CzIPN; the solvent is one of acetonitrile, tetrahydrofuran, N,N-dimethylamide, and dimethyl sulfoxide; and the light source is a blue light source.

[0017] The synthesis method of the photoinduced phosphination process of polyfluoroaromatics of the present invention is as follows:

[0018] 1) A polyfluoroaromatic compound, diphenylphosphine, a photocatalyst, and a solvent are placed in a reaction vessel under nitrogen conditions, and reacted under blue light irradiation to obtain a triarylphosphine compound.

[0019] 2) Oxidizing the above triarylphosphine compound in air to obtain the corresponding phosphine oxide compound.

[0020] The molar ratio of the polyfluoroaromatic hydrocarbon to diphenylphosphine of the present invention is 1-2:1; the molar ratio of the photocatalyst to the polyfluoroaromatic hydrocarbon is 0.001-0.03:1.

[0021] The molar ratio of the polyfluoroaromatic hydrocarbon to diphenylphosphine is 2:1; the molar ratio of the photocatalyst to the polyfluoroaromatic hydrocarbon is 0.03:1. The yield of the final product phosphine oxide compound of the materials with this ratio is high.

[0022] The photocatalyst of the present invention is 4-CzIPN; when the photocatalyst is 4-CzIPN, the yield of the final product is high.

[0023] The solvent of the present invention is dimethyl sulfoxide; when the solvent is dimethyl sulfoxide, the yield of the final product is high; the present invention is carried out in a system of a single organic solvent; if necessary, other organic solvents may also be present in the system, but from the perspective of reaction yield and simplicity of operation, it is preferred not to add other organic solvents, that is, to use a single organic solvent as the reaction solvent.

[0024] The molar concentration of the polyfluoroaromatic hydrocarbon in the solvent is 0.067 mmol / mL; the molar concentration of the diphenylphosphine in the solvent is 0.134 mmol / mL.

[0025] The reaction temperature of the first step reaction and the second step reaction of the present invention is 16-25°C, and the preferred reaction temperature is 25°C.

[0026] The reaction time of the first step reaction of the present invention is 12 to 14 hours, and the reaction time of the second step reaction is 20 to 26 hours. Preferably, the reaction time of the first step reaction is 12 hours, and the reaction time of the second step reaction is 24 hours.

[0027] The reaction of the present invention is carried out under the condition of the presence of a solvent, and the oxidation potential of diphenylphosphine hydrogen is E ox = +1.08V, which can be excited by 4-CzIPN (E ox (PC* / PC -· )=+1.65V vs Ag / AgCl) oxidation. At the same time, pentafluoropyridine (E red =-0.94V vs Ag / AgCl) generated 4-CzIPN -· (E red (PC / PC -· )=-1.18V vs Ag / AgCl) reduction to obtain the target product.

[0028] The advantages of the present invention are that it uses inexpensive and readily available polyfluoroaromatic compounds and diphenylphosphine as reaction substrates, 4-CzIPN as a photocatalyst, and a reaction temperature of room temperature. Under blue light irradiation, a triarylphosphine compound is simply and efficiently synthesized, which is then further oxidized into a phosphine oxide compound. Compared with other methods for synthesizing triarylphosphine compounds, the present invention has the advantages of mild reaction conditions, no heavy metals involved, low-cost raw materials (including polyfluoroaromatics and diphenylphosphine), simple operation, and environmental friendliness. The present invention can be widely used in pharmaceutical synthesis and material synthesis in industry and academia, and has high application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is the H NMR spectrum of (perfluoropyridin-4-yl)diphenylphosphine oxide in Example 1;

[0030] Figure 2is the NMR fluorine spectrum of (perfluoropyridin-4-yl)diphenylphosphine oxide in Example 1;

[0031] Figure 3 is the nuclear magnetic phosphorus spectrum of (perfluoropyridin-4-yl)diphenylphosphine oxide in Example 1;

[0032] Figure 4 is the H NMR spectrum of diphenyl[2,3,5,6-tetrafluoro-4-(trifluoromethyl)phenyl]phosphine oxide in Example 2;

[0033] Figure 5 is the NMR fluorine spectrum of diphenyl[2,3,5,6-tetrafluoro-4-(trifluoromethyl)phenyl]phosphine oxide in Example 2;

[0034] Figure 6 is the nuclear magnetic phosphorus spectrum of diphenyl[2,3,5,6-tetrafluoro-4-(trifluoromethyl)phenyl]phosphine oxide in Example 2;

[0035] Figure 7 is the H NMR spectrum of diphenyl[2,3,5,6-tetrafluorophenyl]phosphine oxide in Example 3;

[0036] Figure 8 is the NMR fluorine spectrum of diphenyl[2,3,5,6-tetrafluorophenyl]phosphine oxide in Example 3;

[0037] Figure 9 is the nuclear magnetic phosphorus spectrum of diphenyl[2,3,5,6-tetrafluorophenyl]phosphine oxide in Example 3;

[0038] Figure 10 is the H NMR spectrum of 4-(diphenylphosphonyl)-2,3,5,6-tetrafluorobenzonitrile in Example 4;

[0039] Figure 11 is the NMR fluorine spectrum of 4-(diphenylphosphonyl)-2,3,5,6-tetrafluorobenzonitrile in Example 4;

[0040] Figure 12 is the nuclear magnetic phosphorus spectrum of 4-(diphenylphosphonyl)-2,3,5,6-tetrafluorobenzonitrile in Example 4;

[0041] Figure 13 is the C NMR spectrum of 4-(diphenylphosphonyl)-2,3,5,6-tetrafluorobenzonitrile in Example 4;

[0042] Figure 14 is the H NMR spectrum of ethyl 4-(diphenylphosphoryl)-2,3,5,6-tetrafluorobenzoate in Example 5;

[0043] Figure 15is the NMR fluorine spectrum of ethyl 4-(diphenylphosphoryl)-2,3,5,6-tetrafluorobenzoate in Example 5;

[0044] Figure 16 is the nuclear magnetic phosphorus spectrum of ethyl 4-(diphenylphosphoryl)-2,3,5,6-tetrafluorobenzoate in Example 5;

[0045] Figure 17 is the H NMR spectrum of methyl 4-(diphenylphosphonyl)-2,3,5-trifluorobenzoate in Example 6;

[0046] Figure 18 is the NMR fluorine spectrum of methyl 4-(diphenylphosphonyl)-2,3,5-trifluorobenzoate in Example 6;

[0047] Figure 19 is the NMR phosphorus spectrum of methyl 4-(diphenylphosphonyl)-2,3,5-trifluorobenzoate in Example 6;

[0048] Figure 20 is the H NMR spectrum of methyl 4-(diphenylphosphoryl)-3,5-difluorobenzoate in Example 7;

[0049] Figure 21 is the NMR fluorine spectrum of methyl 4-(diphenylphosphoryl)-3,5-difluorobenzoate in Example 7;

[0050] Figure 22 is the NMR phosphorus spectrum of methyl 4-(diphenylphosphoryl)-3,5-difluorobenzoate in Example 7;

[0051] Figure 23 is the H NMR spectrum of diphenyl[2,5-difluoro-4-benzoic acid methyl ester]phosphine oxide in Example 8;

[0052] Figure 24 is the NMR fluorine spectrum of diphenyl[2,5-difluoro-4-benzoic acid methyl ester]phosphine oxide in Example 8;

[0053] Figure 25 This is the nuclear magnetic phosphorus spectrum of diphenyl[2,5-difluoro-4-benzoic acid methyl ester]phosphine oxide in Example 8. DETAILED DESCRIPTION

[0054] The present invention will be described in further detail below with reference to the accompanying drawings and specific implementation methods.

[0055] In the present invention, "polyfluoroaromatic hydrocarbon" has the meaning commonly understood by those skilled in the art, i.e., aromatic / heteroaromatic hydrocarbons containing multiple fluorine substituents, such as pentafluoropyridine, octafluorotoluene, pentafluorobenzene, pentafluorobenzonitrile, ethyl pentafluorobenzoate, etc.

[0056] The raw materials used in the following specific examples can all be purchased commercially, and each reagent was purified by means known in the art before use when necessary.

[0057] The raw materials used in the following specific examples can all be purchased commercially, and each reagent was purified by means known in the art before use when necessary.

[0058] 1 H NMR and 13 C NMR measurements were performed using a Bruker Avance 400 spectrometer. The test temperature was room temperature, the solvent was deuterated chloroform, and the reference was selected: 1 H NMR: CHCl3 7.260 ppm; 13 C NMR: CHCl3: 77.000 ppm.

[0059] Example 1: Synthesis of (perfluoropyridin-4-yl)diphenylphosphine oxide

[0060] To an 8mL sample vial under nitrogen and equipped with a magnetic stirrer, the photocatalyst 4-CzIPN (5.0mg, 0.006mmol) and pentafluoropyridine (33.8mg, 1.0eq, 0.2mmol) were added with DMSO (3.0ml) to form a pentafluoropyridine solution. Diphenylphosphine (74.5mg, 2.0eq, 0.4mmol) was then added. The solution was then irradiated with 465nm LED blue light for 12 hours with stirring at room temperature and then continued to be irradiated with blue light in air for 24 hours. After completion of the reaction, the solution was extracted with dichloromethane three times (10mL each time). The combined organic phases were concentrated by rotary evaporation and then subjected to column chromatography to obtain (perfluoropyridin-4-yl)diphenylphosphine oxide in a yield of 71%.

[0061] The product (perfluoropyridin-4-yl) diphenylphosphine oxide (the result is as Figure 1 、 2 and 3): 1 H NMR (400MHz, CDCl3) δ7.83-7.74(m,4H),7.70-7.62(m,2H),7.59-7.51(m,4H)ppm. 19 F NMR (376MHz, CDCl3) δ-88.3--88.6(m,2F),-130.4--130.7(m,2F)ppm. 31 P NMR (162 MHz, CDCl3) δ 20.4 ppm. 13C NMR (101MHz, CDCl3) δ145.5-142.5(m), 141.4-140.3(m), 133.3(d,J=3.0Hz), 131.2(d,J=10.9Hz), 130.0(d,J=112.5Hz), 129.0(d,J=13.4Hz)ppm.

[0062]

[0063]

[0064]

[0065] Standard conditions: pentafluoropyridine 0.2 mmol (1.0 eq), diphenylphosphine 0.4 mmol (2.0 eq), 4-CzIPN (3 mol%), DMSO (3.0 mL), reaction time 12 h, oxidation time 24 h, room temperature, yield is isolated yield. DMSO = dimethyl sulfoxide.

[0066] Example 2: Synthesis of diphenyl[2,3,5,6-tetrafluoro-4-(trifluoromethyl)phenyl]phosphine oxide

[0067] In an 8 mL sample vial under nitrogen and equipped with a magnetic stirrer, the photocatalyst 4-CzIPN (5 mg, 0.006 mmol) and octafluorotoluene (47.2 mg, 1.0 eq, 0.2 mmol) were dissolved in DMSO (3.0 mL) to form an octafluorotoluene solution. Diphenylphosphine (74.5 mg, 2.0 eq, 0.4 mmol) was then added. The solution was then irradiated with 465 nm LED blue light for 12 hours with stirring at room temperature and then continued to be irradiated with blue light in air for 24 hours. After completion of the reaction, the solution was extracted with dichloromethane three times (10 mL each time). The combined organic phases were concentrated by rotary evaporation and then subjected to column chromatography to obtain diphenyl[2,3,5,6-tetrafluoro-4-(trifluoromethyl)phenyl]phosphine oxide in a yield of 78%.

[0068] The product diphenyl[2,3,5,6-tetrafluoro-4-(trifluoromethyl)phenyl]phosphine oxide (the result is as follows Figure 4 、 5 and 6): 1 H NMR (400MHz, CDCl3) δ7.84-7.72(m,4H),7.68-7.60(m,2H),7.60-7.49(m,4H)ppm. 19F NMR (376MHz, CDCl3) δ-56.8 (t, J=21.9Hz, 3F), -126.3--126.8(m,2F), -137.4--138.4(m,2F)ppm. 31 P NMR (162 MHz, CDCl3) δ 20.7 ppm. 13 C NMR (101MHz, CDCl3) δ148.5-145.3(m), 143.0-140.2(m), 133.1(d,J=3.0Hz), 131.1(d,J=1 0.9Hz), 130.7(d,J=112.5Hz), 128.9(d,J=13.4Hz), 121.7-121.4(m), 119.0-118.7(m)ppm.

[0069] Example 3: Synthesis of diphenyl[2,3,5,6-tetrafluorophenyl]phosphine oxide

[0070] To an 8mL sample vial under nitrogen and equipped with a magnetic stirrer, the photocatalyst 4-CzIPN (5.0mg, 0.006mmol) and pentafluorobenzene (33.6mg, 1.0eq, 0.2mmol) were added in DMSO (3.0ml) to form a pentafluorobenzene solution. Diphenylphosphine (74.5mg, 2.0eq, 0.4mmol) was then added. The solution was then irradiated with 465nm LED blue light for 12 hours with stirring at room temperature and then continued to be irradiated with blue light in air for 24 hours. After completion of the reaction, the solution was extracted with dichloromethane three times (10mL each time). The combined organic phases were concentrated by rotary evaporation and then subjected to column chromatography to obtain diphenyl[2,3,5,6-tetrafluorophenyl]phosphine oxide in a 23% yield.

[0071] The product diphenyl[2,3,5,6-tetrafluorophenyl]phosphine oxide (the result is as follows Figure 7 、 8 and 9): 1 H NMR (400MHz, CDCl3) δ7.81-7.72(m,4H),7.64-7.57(m,2H),7.55-7.48(m,4H),7.32-7.22(m,1H)ppm. 19 F NMR (376MHz, CDCl3) δ-128.8--128.9(m,2F),-136.2--136.4(m,2F)ppm. 31 P NMR (162 MHz, CDCl3) δ 20.9 ppm. 13C NMR(101MHz, CDCl3)δ148.3-147.1(m),145.8-144.7(m),132.7(d,J=3.0Hz),131.6( d,J=111.9Hz), 131.1(d,J=10.9Hz), 128.7(d,J=13.2Hz), 110.48(t,J=23.2Hz)ppm.

[0072] Example 4: Synthesis of 4-(diphenylphosphonyl)-2,3,5,6-tetrafluorobenzonitrile

[0073] In an 8 mL sample vial under nitrogen and equipped with a magnetic stirrer, the photocatalyst 4-CzIPN (5.0 mg, 0.006 mmol) and pentafluorobenzonitrile (38.6 mg, 1.0 eq, 0.2 mmol) were added to a solution of pentafluorobenzonitrile (DMSO) (3.0 mL). Diphenylphosphine (74.5 mg, 2.0 eq, 0.4 mmol) was then added. The solution was then irradiated with 465 nm LED blue light for 12 hours with stirring at room temperature and then continued to be irradiated with blue light in air for 24 hours. After completion of the reaction, the solution was extracted with dichloromethane three times (10 mL each time). The combined organic phases were concentrated by rotary evaporation and then subjected to column chromatography to obtain 4-(diphenylphosphono)-2,3,5,6-tetrafluorobenzonitrile in a 34% yield.

[0074] The product 4-(diphenylphosphonyl)-2,3,5,6-tetrafluorobenzonitrile (the result is as Figure 10 、 11 , 12 and 13): 1 HNMR (400MHz, CDCl3) δ7.81-7.71(m,4H),7.68-7.61(m,2H),7.59-7.50(m,4H)ppm. 19 FNMR(376MHz, CDCl3)δ-124.1--126.3(m,2F),-129.7--130.0(m,2F)ppm. 31 P NMR (162 MHz, CDCl3) δ 21.1 ppm. 13 C NMR (101MHz, CDCl3) δ148.7-147.8(m), 146.0-145.2(m), 133.2(d,J=3.0Hz), 131.1(d,J=10 .8Hz), 130.4(d,J=112.5Hz), 129.0(d,J=13.4Hz), 121.0-119.7(m), 106.7(t,J=3.6Hz)ppm.

[0075] Example 5: Synthesis of ethyl 4-(diphenylphosphoryl)-2,3,5,6-tetrafluorobenzoate

[0076] In an 8 mL sample vial protected by nitrogen and equipped with a magnetic stirrer, the photocatalyst 4-CzIPN (5.0 mg, 0.006 mmol) and ethyl pentafluorobenzoate (48 mg, 1.0 eq, 0.2 mmol) were added with DMSO (3.0 ml) to dissolve the resulting ethyl pentafluorobenzoate solution. Diphenylphosphine (74.5 mg, 2.0 eq, 0.4 mmol) was then added. The mixture was then irradiated with 465 nm LED blue light for 12 hours under stirring at room temperature and then continued to be irradiated with blue light in air for 24 hours. After the reaction was complete, the mixture was extracted with dichloromethane three times, 10 mL each time. The organic phases were combined, concentrated by rotary evaporation, and then subjected to column chromatography to obtain ethyl 4-(diphenylphosphoryl)-2,3,5,6-tetrafluorobenzoate in an 83% yield.

[0077] The product 4-(diphenylphosphoryl)-2,3,5,6-tetrafluorobenzoic acid ethyl ester (the result is as Figure 14 、 15 and 16): 1 HNMR (400MHz, CDCl3) δ7.79-7.70(m,4H),7.63-7.57(m,2H),7.54-7.47(m,4H),4.43(q,J=7.1Hz,2H),1.37(t,J=7.2Hz,3H)ppm. 19 F NMR (376MHz, CDCl3) δ-126.5--128.4(m,2F),-136.8--138.1(m,2F)ppm. 31 P NMR (162 MHz, CDCl3) δ 21.0 ppm. 13 C NMR (101MHz, CDCl3) δ158.8,148.3-145.4(m),143.2-140.1(m),132.8(d,J=3.1Hz),131.1( d,J=10.9Hz),131.1(d,J=112.2Hz),128.8(d,J=13.2Hz),117.2-116.1(m),63.1,13.9ppm.

[0078] Example 6: Synthesis of methyl 4-(diphenylphosphonyl)-2,3,5-trifluorobenzoate

[0079] In an 8 mL sample vial protected by nitrogen and equipped with a magnetic stirrer, photocatalyst 4-CzIPN (5.0 mg, 0.006 mmol) and methyl 2,3,4,5-tetrafluorobenzoate (44.4 mg, 1.0 eq, 0.2 mmol) were added with DMSO (3.0 ml) to dissolve the methyl 2,3,4,5-tetrafluorobenzoate solution. Diphenylphosphine (74.5 mg, 2.0 eq, 0.4 mmol) was then added. The mixture was then irradiated with 465 nm LED blue light for 12 hours under stirring at room temperature and then continued to be irradiated with blue light in air for 24 hours. After the reaction was completed, the mixture was extracted with dichloromethane three times, 10 mL each time. The organic phases were combined, concentrated by rotary evaporation, and then subjected to column chromatography to obtain methyl 4-(diphenylphosphonyl)-2,3,5-trifluorobenzoate in an 83% yield.

[0080] The product 4-(diphenylphosphonyl)-2,3,5-trifluorobenzoic acid methyl ester (the result is as follows Figure 17 、 18 and 19): 1 HNMR (400MHz, CDCl3) δ7.79-7.70(m,4H),7.62-7.56(m,2H),7.52-7.46(m,4H),7.45-7.39(m,1H),3.94(s,3H)ppm. 19 F NMR (376MHz, CDCl3) δ-102.9 (d, J = 16.9Hz, 1F), -120.4 (d, J = 21.1Hz, 1F), -137.4--137.6 (m, 1F)ppm. 31 P NMR (162 MHz, CDCl3) δ 20.5 ppm. 13 CNMR(101MHz, CDCl3)δ162.2,158.8-158.5(m),156.2-155.9(m),153.6-153.0(m),132.6(d,J=3.0Hz),131 .5(d,J=111.5Hz),131.1(d,J=10.8Hz),128.7(d,J=13.2Hz),124.4-123.9(m),114.0-113.4(m),53.1ppm.

[0081] Example 7: Synthesis of methyl 4-(diphenylphosphoryl)-3,5-difluorobenzoate

[0082] In an 8 mL sample vial protected by nitrogen and equipped with a magnetic stirrer, the photocatalyst 4-CzIPN (5.0 mg, 0.006 mmol) and methyl 3,4,5-trifluorobenzoate (40.8 mg, 1.0 eq, 0.2 mmol) were added to DMSO (3.0 ml) to dissolve the methyl 3,4,5-trifluorobenzoate solution. Diphenylphosphine (74.5 mg, 2.0 eq, 0.4 mmol) was then added. The mixture was then irradiated with 465 nm LED blue light for 12 hours under stirring at room temperature and then continued to be irradiated with blue light in air for 24 hours. After the reaction was completed, the mixture was extracted with dichloromethane three times, 10 mL each time. The organic phases were combined, concentrated by rotary evaporation, and then subjected to column chromatography to obtain methyl 4-(diphenylphosphoryl)-3,5-difluorobenzoate in a yield of 54%.

[0083] The product 4-(diphenylphosphoryl)-3,5-difluorobenzoic acid methyl ester (the result is as Figure 20 、 21 and 22): 1 HNMR (400MHz, CDCl3) δ7.79-7.70(m,4H),7.60-7.52(m,4H),7.51-7.45(m,4H),3.92(s,3H)ppm. 19 F NMR(376MHz, CDCl3)δ-96.2(s,2F)ppm. 31 P NMR (162 MHz, CDCl3) δ 20.6 ppm. 13 C NMR (101MHz, CDCl3) δ163.9,163.5(dd,J=256.5,7.7Hz),136.7(t,J=10.2Hz),132.3(d,J=3.0H z), 132.1 (d, J = 111.3Hz), 131.1 (d, J = 10.6Hz), 128.6 (d, J = 13.1Hz), 113.7-113.2 (m), 52.9ppm.

[0084] Example 8: Synthesis of diphenyl[2,5-difluoro-4-benzoic acid methyl ester]phosphine oxide

[0085] In an 8 mL sample vial under nitrogen and equipped with a magnetic stirrer, the photocatalyst 4-CzIPN (5.0 mg, 0.006 mmol) and methyl 2,4,5-trifluorobenzoate (40.8 mg, 1.0 eq, 0.2 mmol) were added to a DMSO (3.0 mL) solution to form methyl 2,4,5-trifluorobenzoate. Diphenylphosphine (74.5 mg, 2.0 eq, 0.4 mmol) was then added. The mixture was then irradiated with 465 nm LED blue light for 12 hours under stirring at room temperature and then continued to be irradiated with blue light in air for 24 hours. After completion of the reaction, the mixture was extracted with dichloromethane three times (10 mL each time). The combined organic phases were concentrated by rotary evaporation and then subjected to column chromatography to obtain diphenyl[methyl 2,5-difluoro-4-benzoate]phosphine oxide in a 47% yield.

[0086] The product diphenyl[2,5-difluoro-4-benzoic acid methyl ester]phosphine oxide (the result is as follows Figure 23 、 24 and 25): 1 HNMR (400MHz, CDCl3) δ7.77-7.66(m,5H),7.63-7.53(m,3H),7.50-7.43(m,4H),3.91(s,3H)ppm. 19 F NMR (376 MHz, CDCl3) δ -105.2 (dd, J = 20.3, 3.8 Hz, 1F), -113.3 (dd, J = 20.3, 2.3 Hz, 1F) ppm. 31 P NMR (162 MHz, CDCl3) δ22.9 ppm. 13 C NMR (101 MHz, CDCl3) δ163.1, 158.9-158.6 (m), 156.4-156.0 (m), 132.6 (d, J = 2.9 Hz), 131.6 (d, J = 10.7 Hz), 130.6 (d, J = 109.5 Hz), 128.7 (d, J = 12.9 Hz), 123.8-123.4 (m), 123.3-122.7 (m), 119.1 (dd, J = 27.7, 6.4 Hz), 52.8 ppm.

[0087]

[0088]

[0089] Example 9: Lighting Experiment

[0090] With other conditions unchanged, the technical solution in Example 1 was tested using ultraviolet light, no light, and white light, and the results were as follows:

[0091] Experimental group Lighting conditions Yield of (perfluoropyridin-4-yl)diphenylphosphine oxide Example 1 Blu-ray 71％ Comparative Example 1 No light 0 Comparative Example 2 UV rays 50％ Comparative Example 3 White light 30％

[0092] Therefore, the optimal light source for the reaction conditions of this process is a blue light source, at which time the final yield of the product can reach the maximum.

[0093] It should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any combination or equivalent transformation based on the above embodiments falls within the scope of protection of the present invention.

Claims

1. A photoinduced phosphination process of polyfluoroaromatic hydrocarbons, characterized in that: The synthesis method of the process is as follows: ； Wherein, X is C or N, R is H, trifluoromethyl and C2-C5 ester group; n is the number of substituents F, n is 2-4; The catalyst is 4-CzIPN, the solvent is dimethyl sulfoxide, the light source is a blue light source, and polyfluoroaromatic hydrocarbons react with diphenylphosphine under nitrogen conditions.

2. The phosphination process according to claim 1, wherein The synthetic method comprises the following steps: 1) A polyfluoroaromatic compound, diphenylphosphine, a photocatalyst, and a solvent are placed in a reaction vessel under nitrogen conditions, and reacted under blue light irradiation to obtain a triarylphosphine compound; 2) Oxidizing the triarylphosphine compound obtained in step 1) in air to obtain the corresponding phosphine oxide compound.

3. The phosphination process according to claim 1 or 2, wherein: The molar ratio of the polyfluoroaromatic hydrocarbon to diphenylphosphine is 1-2:1; the molar ratio of the photocatalyst to the polyfluoroaromatic hydrocarbon is 0.001-0.03:

1.

4. The phosphination process according to claim 3, wherein The molar ratio of the polyfluoroaromatic hydrocarbon to diphenylphosphine is 2:1; the molar ratio of the photocatalyst to the polyfluoroaromatic hydrocarbon is 0.03:

1.

5. The phosphination process according to claim 1 or 2, wherein: The molar concentration of the polyfluoroaromatic hydrocarbon in the solvent is 0.067 mmol / mL; the molar concentration of the diphenylphosphine in the solvent is 0.134 mmol / mL.

6. The phosphination process according to claim 2, wherein The reaction temperature of the first step reaction and the second step reaction is 16-25°C.

7. The phosphination process according to claim 2, wherein The reaction time of the first step reaction is 12-14 h, and the reaction time of the second step reaction is 20-26 h.

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