A method for preparing a perfluorobisfluorosulfonyl monomer

Abstract

Disclosed herein is a method for preparing a perfluorobisfluorosulfonyl monomer. Specifically, disclosed herein is a method for preparing a compound of Formula II, comprising the step of: subjecting a compound of Formula III to a sulfinic dehalogenation reaction as shown below in the presence of a sulfinic dehalogenation reagent in an organic solvent to obtain the compound of Formula II. The method of the present application is a method for preparing an intermediate of a perfluorobisfluorosulfonyl monomer, and is also a key step in a method for preparing a perfluorobisfluorosulfonyl monomer. The method of the present application is simple to purify and has a relatively high yield.

Description

Technical Field

[0001] This invention relates to a method for preparing a perfluorobisfluorosulfonyl monomer. Background Technology

[0002] Perfluorobisfluorosulfonyl monomers are an important class of organic fluorine-containing intermediates, serving as crucial raw materials for the production of ionic liquids (JP2018170432A), proton-conducting membranes (CN104447435A), photoactive materials (US2008131810), solid polymeric electrolytes (JP2013129694 A), and other fluorine-containing fine chemicals. In addition to possessing the hydrophobic and oleophobic properties and high chemical stability characteristic of fluorine-containing materials, their unique bilateral fluorosulfonyl structure allows them to link with other functional groups, making them a vital intermediate in the field of fluorine-containing materials.

[0003] The traditional preparation method of perfluorobisfluorosulfonyl monomers mainly involves the following three-step reaction: utilizing the product [FO2SCF2CF2O(CF2)] produced by the telomerization of tetrafluorosulfonyl lactone and tetrafluoroethylene. n(n=0,2,4) Using CF2CF2I as raw material, a sulfinization dehalogenation reaction was first carried out to prepare sodium perfluorinated double-sided sulfinate [NaO2SCF2CF2O(CF2)]. n(n=0,2,4) The product [CF2CF2SO2Na] was then reacted with chlorine gas to yield the perfluorodichlorosulfonyl product [ClO2SCF2CF2O(CF2)]. n(n=0,2,4) The monomer [CF2CF2SO2Cl] is then subjected to a fluorine-chlorine exchange reaction to obtain the perfluorobisfluorosulfonyl monomer [FO2SCF2CF2O(CF2)]. n(n=0,2,4) CF2CF2SO2F]. (J. Fluorine. Chem. 1993, 60, 93; J. Fluorine. Chem. 2014, 160, 12; US2008131810)

[0004]

[0005] The purification process of the first step in this synthetic method, involving the sodium perfluorobilateral sulfinate product, is difficult and hygroscopic. The second step requires the use of toxic chlorine gas, posing a high risk and resulting in a low yield. The overall yield of the three steps is approximately 40.7%, which is not ideal. Therefore, developing a simple and safe method for the direct synthesis of perfluorobisfluorosulfonyl monomers is of paramount importance. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the defects of the prior art, such as long reaction steps, environmental unfriendliness and low yield, and to provide a method for preparing perfluorobisfluorosulfonyl monomers with fewer reaction steps, environmental friendliness and better yield.

[0007] The present invention solves the above-mentioned technical problems through the following technical solutions.

[0008] The present invention provides a method for preparing a compound of formula II, comprising the following steps: in an organic solvent, in the presence of a sulfinating dehalogenating agent, a compound of formula III undergoes a sulfinating dehalogenating reaction as shown below to obtain a compound of formula II;

[0009] ;

[0010] Where n is 0-4, for example 0, 2 or 4; M is an alkali metal salt.

[0011] In some embodiments, the compound of formula III is , or .

[0012] In some embodiments, M is potassium or sodium.

[0013] In some embodiments, the organic solvent is selected from one or more of amide solvents, sulfoxide solvents, nitrile solvents, and ether solvents, for example, one or more of sulfoxide solvents, nitrile solvents, and ether solvents, or even more specifically, one or more of sulfoxide solvents and ether solvents, or sulfoxide solvents or ether solvents.

[0014] In some embodiments, the amide solvent is N,N-dimethylformamide and / or N,N-dimethylacetamide.

[0015] In some embodiments, the sulfoxide solvent is dimethyl sulfoxide.

[0016] In some embodiments, the nitrile solvent is acetonitrile.

[0017] In some embodiments, the ether solvent is dioxane and / or tetrahydrofuran, such as dioxane or tetrahydrofuran.

[0018] In some embodiments, the volume-to-mass ratio of the organic solvent to the compound of formula III is 1-3 ml / g, for example 2.3 ml / g, 1.9 ml / g or 1.6 ml / g.

[0019] In some embodiments, the sulfonating dehalogenating agent is selected from one or more of alkali metal sulfites, alkali metal bisulfites, alkali metal dithionites, alkali metal pyrosulfites, alkali metal hydroxymethyl sulfinates, and sulfur dioxide compounds (referring to thiourea compounds containing thiourea dioxide groups), for example, selected from one or more of alkali metal sulfites, alkali metal bisulfites, and alkali metal pyrosulfites, or for example, alkali metal sulfites, alkali metal bisulfites, or alkali metal pyrosulfites.

[0020] In some embodiments, the alkali metal sulfite is potassium sulfite (K2SO3) and / or sodium sulfite (Na2SO3), for example, potassium sulfite (K2SO3) or sodium sulfite (Na2SO3).

[0021] In some embodiments, the alkali metal bisulfite is sodium bisulfite (NaHSO3) and / or potassium bisulfite (KHSO3), for example, sodium bisulfite (NaHSO3).

[0022] In some schemes, the alkali metal dithionite is sodium dithionite (Na2S2O4).

[0023] In some schemes, the alkali metal metabisulfite is sodium metabisulfite (Na2S2O5).

[0024] In some embodiments, the alkali metal hydroxymethyl sulfinate is sodium hydroxymethyl sulfinate (HOCH2SO2Na).

[0025] In some embodiments, the sulfur dioxide compound is thiourea dioxide.

[0026] In some embodiments, the molar ratio of the sulfonated dehalogenating agent to the compound of formula III is (0.1-10):1, for example (3-5):1, or for example 3:1, 3.3:1, 4:1 or 5:1.

[0027] In some schemes, the reaction temperature of the sulfonation dehalogenation reaction is 35-60°C, for example 40-50°C, or even 40°C, 45°C, or 50°C.

[0028] In this invention, the reaction time of the sulfonation dehalogenation reaction is the conventional reaction time of sulfonation dehalogenation reactions in the art.

[0029] In some schemes, the sulfonation dehalogenation reaction is performed using commonly used testing methods in the art (such as CG-MS, HPLC, etc.). 19 The reaction is monitored by fluorocarbon-natured magnetic resonance (F-NMR), and the endpoint is generally defined as the disappearance of the raw material peak or the cessation of reaction. The reaction time for the sulfonation dehalogenation reaction can be 1-5 h, for example, 2 h, 3 h, or 4 h.

[0030] In this invention, the materials for the sulfonation dehalogenation reaction consist of an organic solvent, a sulfonation dehalogenation reagent, and a compound of formula III.

[0031] In this invention, the operation of the sulfonation dehalogenation reaction is a conventional operation of sulfonation dehalogenation reaction in the art.

[0032] In some embodiments, the sulfonation dehalogenation reaction includes the following steps: mixing an organic solvent and a compound of formula III, then mixing the mixture with a sulfonation dehalogenation reagent to carry out the sulfonation dehalogenation reaction.

[0033] In some embodiments, the sulfonation dehalogenation reaction is carried out under stirring.

[0034] In some embodiments, the stirring rate may be 100-1000 rpm, for example 500-1000 rpm.

[0035] In some schemes, the sulfonation dehalogenation reaction is carried out by absorbing the gas released from the reaction with an alkaline solution.

[0036] In some embodiments, the alkaline solution may be a sodium hydroxide alkaline solution.

[0037] In some embodiments, the sodium hydroxide alkaline solution may be 1.0 M.

[0038] In this invention, the post-treatment of the sulfonation dehalogenation reaction is a conventional post-treatment of the sulfonation dehalogenation reaction in the art.

[0039] In some schemes, the post-treatment of the sulfonation dehalogenation reaction includes the following steps: extraction with an extractant and concentration.

[0040] In some embodiments, the extract in the post-treatment of the sulfonation dehalogenation reaction may be a mixture of organic solvent and water.

[0041] In some embodiments, the organic solvent may be ethyl acetate, dichloromethane, or petroleum ether, such as ethyl acetate or dichloromethane.

[0042] In some embodiments, the volume ratio of water to organic solvent may be (1-3):1, for example 2:1.

[0043] The present invention also provides a method for preparing a compound of formula I, comprising the following steps: in an organic solvent, in the presence of a fluorinating agent, a compound of formula II undergoes an oxidative fluorination reaction to obtain a compound of formula I;

[0044] ;

[0045] Where n is 0-4, for example 0, 2 or 4; M is an alkali metal salt.

[0046] In some embodiments, the compound of formula II is , or .

[0047] In some schemes, M is sodium or potassium.

[0048] In this invention, the organic solvent is a conventional organic solvent used in oxidative fluorination reactions in the art.

[0049] In some embodiments, the organic solvent is selected from one or more of alcohol solvents, ketone solvents, amide solvents, nitrile solvents, ether solvents, sulfoxide solvents and haloalkane solvents, for example, selected from one or more of ether solvents, amide solvents and sulfoxide solvents, or for example, ether solvents, amide solvents or sulfoxide solvents.

[0050] In some embodiments, the alcohol solvent is methanol and / or isopropanol.

[0051] In some embodiments, the ketone solvent is 1,3-dimethyl-2-imidazolinone.

[0052] In some embodiments, the amide solvent is N,N-dimethylacetamide and / or N,N-dimethylformamide, for example, N,N-dimethylformamide.

[0053] In some embodiments, the nitrile solvent is acetonitrile.

[0054] In some embodiments, the ether solvent is selected from one or more of tetrahydrofuran, dioxane, diethylene glycol dimethyl ether, and tetraethylene glycol dimethyl ether, for example, tetrahydrofuran.

[0055] In some embodiments, the sulfoxide solvent is dimethyl sulfoxide.

[0056] In some embodiments, the haloalkane solvent is dichloromethane.

[0057] In some embodiments, the volume-to-mass ratio of the organic solvent to the compound of formula II is 1-4 ml / g, for example 2.5 ml / g, 2.1 ml / g, 1.7 ml / g or 2.6 ml / g.

[0058] In this invention, the fluorinating agent is a conventional fluorinating agent used in oxidative fluorination reactions in the art.

[0059] In some embodiments, the fluorinating agent is a nucleophilic fluorinating agent and / or an electrophilic fluorinating agent.

[0060] In some embodiments, the nucleophilic fluorinating reagent is selected from one or more of diethylaminosulfur trifluoride (DAST), sulfur tetrafluoride (SF4), bis(2-methoxyethyl)aminosulfur trifluoride (Deoxo-Fluor), (diethylamino)difluorosulfonium tetrafluoroborate (XtalFluor-E), 4-tert-butyl-2,6-dimethylphenylsulfur trifluoride (Fluolead), 2-chloro-1,3-bis(2,6-diisopropylphenyl)-1H-imidazolium chloride-cesium fluoride (PhenoFluor), and hydrogen fluoride-pyridine complexes (Olah's reagent), such as diethylaminosulfur trifluoride (DAST).

[0061] In some embodiments, the electrophilic fluorinating agent is selected from one or more of N-fluorobisbenzenesulfonamide (NFSI), N-fluorobisbenzenesulfonamide (NFSA), N-fluoropyridine trifluoromethanesulfonate, and 1-fluoro-4-methyl-1,4-diazabicyclo[2.2.2]octanetetrafluoroborate (Selectfluor), such as N-fluorobisbenzenesulfonamide (NFSI), N-fluorobisbenzenesulfonamide (NFSA), or 1-fluoro-4-methyl-1,4-diazabicyclo[2.2.2]octanetetrafluoroborate (Selectfluor).

[0062] In some embodiments, the molar ratio of the fluorinating agent to the compound of formula II is (1-5):1, for example 1:1 or 4:1.

[0063] In some embodiments, the reaction temperature of the oxidative fluorination reaction is 0-30°C, for example, 20-30°C.

[0064] In this invention, the reaction time of the oxidative fluorination reaction is the conventional reaction time of oxidative fluorination reactions in the art.

[0065] In some schemes, the reaction time of the oxidative fluorination reaction is determined using methods commonly used in the art (such as CG-MS, HPLC, etc.). 19 The reaction is monitored by fluorocarbon spectroscopy (F-NMR), and the endpoint is generally defined as the disappearance of the starting material peak or the cessation of the reaction. The reaction time for the oxidative fluorination reaction can be 1-15 h, for example, 2 h, 5 h, 8 h or 10 h.

[0066] In this invention, the operation of the oxidative fluorination reaction is a conventional operation of oxidative fluorination reaction in the art.

[0067] In some embodiments, the oxidative fluorination reaction includes the following steps: mixing the compound of formula II and the solvent, then adding the oxidative fluorination reagent in batches to carry out the oxidative fluorination reaction.

[0068] In some schemes, the oxidative fluorination reaction can be carried out in batches of 2-5 times, for example, 3 times.

[0069] In some embodiments, the oxidative fluorination reaction is carried out under stirring.

[0070] In some embodiments, the stirring rate may be 100-1000 rpm, for example 500-1000 rpm.

[0071] In some schemes, the oxidative fluorination reaction is carried out by absorbing the gas released from the reaction with an alkaline solution.

[0072] In some embodiments, the alkaline solution may be a sodium hydroxide alkaline solution.

[0073] In some embodiments, the sodium hydroxide alkaline solution may be 1.0 M.

[0074] In this invention, the post-treatment of the oxidative fluorination reaction is a conventional post-treatment of the oxidative fluorination reaction in the art.

[0075] In some embodiments, the post-treatment of the oxidative fluorination reaction includes the following steps: adding water to allow the fluorine phase to precipitate and accumulate at the bottom, followed by separation.

[0076] In some embodiments, the compound of formula I is prepared by means of the following steps:

[0077] In an organic solvent, in the presence of a sulfinizing dehalogenating agent, compound III undergoes the sulfinizing dehalogenating reaction shown below to give compound II;

[0078] ;

[0079] Where n and M are as described above;

[0080] The conditions and procedures for the sulfonation dehalogenation reaction are the same as described above.

[0081] This invention provides a compound of formula II;

[0082] ;

[0083] Where n and M are as described above.

[0084] Without violating common sense in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0085] The reagents and raw materials used in this invention are all commercially available.

[0086] The positive and progressive effects of this invention are as follows:

[0087] (1) This invention provides a method for preparing a perfluorodifluorosulfonyl monomer intermediate with better yield, mild reaction conditions and environmental friendliness;

[0088] (2) The present invention also provides a method for preparing perfluorobisfluorosulfonyl monomers with fewer reaction steps, environmental friendliness, simple purification and better yield. Detailed Implementation

[0089] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.

[0090] The structure and purity of the compound were determined by nuclear magnetic resonance (NMR). 19 The determination was performed using nuclear magnetic resonance (NMR) technology, with a Bruker AVANCE 400 instrument used to determine the deuterated solvent, which was the solvent used in the reaction.

[0091] Example 1

[0092] (1)

[0093] DMSO (300 mL) solvent was added to a 1 L flask containing a stir bar. 127.8 g (0.3 mol) of the raw material shown in formula (III-1) was weighed and added to the reaction flask, resulting in a bright yellow reaction system. Then, 209.1 g (1.2 mol) of the dehalogenating reagent K₂SO₃ was weighed. The reaction released a large amount of gas. A tube was connected to the reaction flask and 1.0 M sodium hydroxide solution was introduced for absorption. The flask was heated to 50 °C in an oil bath and reacted for 3 h with vigorous stirring. After the disappearance of CF₂I detected by fluorine spectroscopy, 2 L of water and 1 L of DCM were added for extraction. The lower organic phase was retained, and the resulting yellow solution was concentrated using a diaphragm pump to obtain potassium sulfinate as shown in formula (II-1), with a yield as high as 99%. 19 F NMR (376 MHz, Chloroform-d) δ ppm 45.27 (t, J = 6.4 Hz,1F), -81.56 – -81.80 (m,2F), -82.15 (dt, J = 12.1, 8.1 Hz,2F), -112.25 (t, J = 8.4Hz,2F), -133.49 (t, J = 15.1 Hz, 2F).

[0094] (2)

[0095] In a 500 mL round-bottom flask containing 119.5 g of potassium sulfinate as shown in formula (II-1), a suitable magnetic stir bar was added, followed by 300 mL of THF solvent. The reaction flask was placed in a room temperature water bath and stirred until the sulfinate was dissolved. Then, 94.6 g (0.3 mol) of NFSI was added in three batches. During the reaction, the system color lightened and heat was released, so an ice-water bath was used to cool the system to prevent overheating. The generated gas was absorbed with sodium hydroxide solution, and the reaction was carried out at room temperature for 5 h. Fluorine spectroscopy revealed that the system consisted of three phases: a lower fluorine phase, a middle white solid, and an upper colorless liquid. A large amount of water was added to the system, causing the product shown in formula (I-1) to become a separate fluorine phase, concentrated at the bottom of the reaction solution. After separation, a total of 102.1 g of product was obtained, with an overall yield of 89% and a purity of 97%. 19 F NMR (376 MHz, Chloroform-d) δppm 46.17 (d, J = 5.3Hz, 2F), -81.77 (d, J = 3.5 Hz, 4F), -112.20 (d, J = 5.8 Hz, 4F).

[0096] Example 2

[0097] (1)

[0098] 1 L of Dioxane solvent was added to a 2 L three-necked flask equipped with a mechanical stirrer. 526.0 g (1 mol) of the raw material shown in formula (III-2) was weighed and added to the reaction flask. The reaction system separated into layers, with the bottom layer being a separate fluorine phase. At this point, 960.6 g (5 mol) of the dehalogenating reagent Na₂S₂O₅ was weighed and placed in an oil bath and heated to 40 °C. The reaction was carried out for 3 h with vigorous stirring. The system was a bright yellow solid-liquid mixture, and a large amount of gas was released during the reaction. The gas was absorbed using sodium hydroxide solution. After the reaction was confirmed to be complete by fluorine spectroscopy, 4 L of water and 2 L of EA were added and stirred for 30 min. The mixture was allowed to stand for 30 min, and the system separated into layers. The organic phase was retained and collected, then concentrated using a diaphragm pump to obtain a pale yellow viscous liquid, 481.0 g of sodium sulfite salt shown in formula (II-2), with a yield of 99%. 19F NMR (376MHz, Chloroform-d) δppm 45.51 (s, 1F), -82.59 – -83.34 (m, 2F), -83.52 – -84.46 (m, 2F), -113.77 (d, J = 6.9 Hz, 2F), -113.91 – -114.66 (m, 2F), -125.47 (dd, J = 13.6, 5.8 Hz, 2F), -133.21 – -133.70 (m, 2F).

[0099] (2)

[0100] In a 2 L round-bottom flask containing sodium sulfite as shown in formula (II-2), add 1 L of solvent DMF, and mechanically stir to dissolve the sodium sulfite in the system. Add Selective Fluor in three batches. A total of 354.3 g (1.0 mol) was added. The system color lightened to white, and exothermic phenomena were observed. The temperature was maintained in an ice-water bath, not exceeding 50°C. After the addition was complete, the reaction was allowed to proceed at room temperature for 8 hours. Fluorine spectroscopy revealed that the system consisted of three phases: a pale yellow liquid at the bottom, a white solid in the middle, and a pale yellow liquid at the top. A large amount of water was added to the system, causing the product shown in formula (I-2) to become a separate fluorine phase, concentrated at the bottom of the reaction solution. After separation, a total of 448.2 g of the colorless, transparent liquid product shown in formula (I-2) was obtained, with an overall yield of 93% and a purity of 96%. 19 F NMR(376 MHz, Chloroform-d) δppm 44.09(s, 1F), 44.97(s, J = 15.7 Hz, 1F), -83.23(d, J = 15.7 Hz, 2F), -84.17 (d, J = 16.2 Hz, 2F), -110.30(d,J = 15.4 Hz, 2F), -120.08 (d, J = 13.6 Hz, 2F), -123.31 (q, J = 9.1 Hz, 2F).

[0101] Example 3

[0102] (1)

[0103] DMSO (500 mL) solvent was added to a 1 L reactor equipped with mechanical stirring. 321.9 g (0.5 mol) of the raw material shown in formula (III-3) was weighed and added to the reactor. The reaction system was yellow after dissolution. Then, 156.1 g (1.5 mol) of the sulfinizing dehalogenating reagent NaHSO3 was weighed. The reactor was placed in a furnace and heated to 45°C. The reaction was carried out for 2 h with vigorous stirring. A large amount of sulfur dioxide gas was released during the reaction. It was important to ensure that the internal pressure of the reaction was not too high; the gas was absorbed using sodium hydroxide solution. After the reaction was confirmed to be complete by fluorine spectrum analysis, 1 L of water was added to dissolve the gas, followed by 0.5 L of EA and stirring for 1 h. The pale yellow filtrate was collected and concentrated using a diaphragm pump to obtain a yellow viscous liquid, which was 290.0 g of sodium sulfite salt shown in formula (II-2), with a yield of 99%. 19 F NMR (376 MHz, DMSO-d6) δ ppm 45.66(s, 1F), -81.00 (d, J = 5.3 Hz, 2F), -84.23 (t, J = 5.8 Hz, 2F), -114.68 (d, J = 16.3 Hz, 2F), -116.43–-116.58 (m, 2F), -122.87– -123.11(m, 2F), -123.35–-123.59(m, 2F), -124.59–-124.69(m, 2F), -133.98 (d, J = 15.8Hz, 2F).

[0104] (2)

[0105] In a 1 L round-bottom flask containing sodium sulfite as shown in formula (II-3), add a suitable magnetic stir bar, then add 500 mL of solvent DMSO. Place the flask in an ice-water bath and start stirring to dissolve the sulfite. Then add NFSA in three batches. A total of 508 g (2 mol) was added. Bubbles were emitted during the reaction, and the gas was absorbed by sodium hydroxide solution. An exothermic reaction was observed; the temperature was kept below 40°C. After addition, the reaction was allowed to proceed at room temperature for 2 hours. Fluorine chromatography revealed three phases after the reaction: a pale yellow liquid at the bottom, a white solid in the middle, and a pale yellow liquid at the top. Adding a large amount of water caused the fluorine phase to accumulate at the bottom of the reaction mixture, appearing as a pale yellow liquid. After separation, a total of 289 g of the product shown in formula (I-3) was obtained, with an overall yield of 89% and a purity of 95%. 19F NMR (376 MHz, Chloroform-d) δ ppm 45.76(s, 1F), 45.66(s, 1F), -81.00(d, J = 5.6 Hz, 2F), -85.60(t, J = 5.4 Hz, 2F), -111.31(d, J = 14.3 Hz,2F), -112.12– -112.26(m, 2F), -120.85– -120.96(m, 2F), -122.40– -122.49(m,2F), -123.35– -123.53(m, 2F), -124.59 (d, J = 15.8 Hz, 2F).

[0106] Example 4

[0107] (1)

[0108] In a 5 L reactor equipped with mechanical stirring, 2 L of solvent THF was added. 852 g (3 mol) of the raw material shown in formula (III-1) was weighed and added to the reactor. After the reaction system was dissolved, it became a yellow liquid. Then, 1260.4 g (10 mol) of dehalogenating reagent Na₂SO₃ was weighed. The reactor was placed in an electric furnace and heated to 50°C. The reaction was carried out for 4 h with vigorous stirring. A large amount of gas was released during the reaction, which was absorbed using alkaline sodium hydroxide solution. After the reaction was confirmed to be complete by fluorine spectroscopy, the reactor was opened, 4 L of water and 2 L of DCM were added, and the mixture was stirred vigorously for another 2 h. The lower pale yellow solution was collected and concentrated using a diaphragm pump to obtain a viscous liquid, 1146.0 g of sodium sulfite salt shown in formula (II-1), with a yield of 99%. 19 F NMR (376 MHz, Chloroform-d)δ ppm 45.21 (p, J = 6.4 Hz, 1F), -81.71 (dd, J = 16.9, 9.1 Hz, 2F), -82.12 – -82.25 (m, 2F), -112.26 – -112.34 (m, 2F), -133.68(s, 2F).

[0109] (2)

[0110] In a 5 L round-bottom flask containing sodium sulfite as shown in formula (II-4), add a suitable mechanical stirrer, then add 3 L of solvent THF. Place the reaction flask in an ice-water bath and turn on the mechanical stirrer to dissolve the sodium sulfite. Then add DAST in 3 batches. A total of 478.7 g of the product was collected. The reaction releases heat, so the temperature should not exceed 50°C. After the addition of the product, the reaction was allowed to proceed at room temperature for 10 hours. Fluorine chromatography revealed that the system consisted of three layers: a pale yellow liquid at the bottom, a white solid in the middle, and a pale yellow liquid at the top. Adding a large amount of water quenched the reaction, causing the fluorine phase to accumulate at the bottom of the reaction solution, appearing as a nearly colorless liquid. After separation, a total of 1077.0 g of the product shown in formula (I-1) was obtained, with an overall yield of 94% and a purity of 97%. 19 F NMR (376MHz, Chloroform-d) δ ppm 46.21 (q, J = 5.6, 4.6 Hz, 2F), -81.74 (t, J = 3.3Hz, 4F), -112.17 (d, J = 5.9 Hz, 4F).

Claims

1. A method for preparing a compound of formula II, characterized in that, It includes the following steps: In an organic solvent, in the presence of a sulfinizing dehalogenating agent, compound III undergoes the sulfinizing dehalogenating reaction shown below to give compound II; Where n is 0-4; M is an alkali metal salt.

2. The method for preparing the compound of formula II as described in claim 1, characterized in that, It meets one or more of the following conditions: (1) The n mentioned is 0, 2 or 4; (2) M is potassium or sodium; (3) The organic solvent is selected from one or more of amide solvents, sulfoxide solvents, nitrile solvents and ether solvents; (4) The volume-to-mass ratio of the organic solvent to the compound of formula III is 1-3 ml / g; (5) The sulfonation dehalogenating reagent is selected from one or more of alkali metal sulfites, alkali metal bisulfites, alkali metal dithionites, alkali metal metabisulfites, alkali metal hydroxymethyl sulfinates and sulfur dioxide compounds; (6) The molar ratio of the sulfonated dehalogenating reagent to the compound of formula III is (0.1-10):1; (7) The reaction temperature of the sulfonation dehalogenation reaction is 35-60℃; (8) The materials for the sulfonation dehalogenation reaction consist of an organic solvent, a sulfonation dehalogenation reagent, and a compound of formula III; and (9) The operation of the sulfonation dehalogenation reaction includes the following steps: mixing the organic solvent and the compound of formula III, and then mixing them with the sulfonation dehalogenation reagent to carry out the sulfonation dehalogenation reaction.

3. The method for preparing the compound of formula II as described in claim 2, characterized in that, It meets one or more of the following conditions: (1) The compound of formula III is , or ; (2) The amide solvent is N,N-dimethylformamide and / or N,N-dimethylacetamide; (3) The sulfoxide solvent is dimethyl sulfoxide; (4) The nitrile solvent is acetonitrile; (5) The ether solvent is dioxane and / or tetrahydrofuran; (6) The volume-to-mass ratio of the organic solvent to the compound of formula III is 2.3 ml / g, 1.9 ml / g, or 1.6 ml / g; (7) The alkali metal sulfite is potassium sulfite and / or sodium sulfite; (8) The alkali metal bisulfite is sodium bisulfite and / or potassium bisulfite; (9) The alkali metal dithionite mentioned is sodium dithionite; (10) The alkali metal metabisulfite mentioned is sodium metabisulfite; (11) The alkali metal hydroxymethyl sulfinate is sodium hydroxymethyl sulfinate; (12) The sulfur dioxide compound is thiourea dioxide; (13) The molar ratio of the sulfonated dehalogenating reagent to the compound of formula III is (3-5):1; and (14) The reaction temperature of the sulfonation dehalogenation reaction is 40-50℃.

4. The method for preparing the compound of formula II as described in claim 3, characterized in that, It meets one or more of the following conditions: (1) The ether solvent is dioxane or tetrahydrofuran; (2) The alkali metal sulfite is potassium sulfite or sodium sulfite; (3) The alkali metal bisulfite is sodium bisulfite; (4) The molar ratio of the sulfonated dehalogenating agent to the compound of formula III is 3:1, 3.3:1, 4:1, or 5:1; and (5) The reaction temperature of the sulfonation dehalogenation reaction is 40℃, 45℃ or 50℃.

5. A method for preparing a compound of formula I, characterized in that, It includes the following steps: In an organic solvent, in the presence of a fluorinating agent, compound II undergoes an oxidative fluorination reaction to yield compound I. ； Where n is 0-4; M is an alkali metal salt.

6. The method for preparing the compound of formula I as described in claim 5, characterized in that, It meets one or more of the following conditions: (1) The n mentioned is 0, 2 or 4; (2) M is sodium or potassium; (3) The organic solvent is selected from one or more of alcohol solvents, ketone solvents, amide solvents, nitrile solvents, ether solvents, sulfoxide solvents and haloalkane solvents; (4) The volume-to-mass ratio of the organic solvent to the compound of formula II is 1-4 ml / g; (5) The fluorinating agent is a nucleophilic fluorinating agent and / or an electrophilic fluorinating agent; (6) The molar ratio of the fluorinating agent to the compound of formula II is (1-5):1; (7) The reaction temperature of the oxidative fluorination reaction is 0-30℃; and (8) The operation of the oxidative fluorination reaction includes the following steps: after mixing the compound of formula II and the solvent, the fluorinating reagent is added in batches to carry out the oxidative fluorination reaction.

7. The method for preparing the compound of formula I as described in claim 6, characterized in that, It meets one or more of the following conditions: (1) The compound of formula II is , or ; (2) The alcohol solvent is methanol and / or isopropanol; (3) The ketone solvent is 1,3-dimethyl-2-imidazolinone; (4) The amide solvent is N,N-dimethylacetamide and / or N,N-dimethylformamide; (5) The nitrile solvent is acetonitrile; (6) The ether solvent is selected from one or more of tetrahydrofuran, dioxane, diethylene glycol dimethyl ether and tetraethylene glycol dimethyl ether; (7) The sulfoxide solvent is dimethyl sulfoxide; (8) The haloalkane solvent is dichloromethane; (9) The volume-to-mass ratio of the organic solvent to the compound of formula II is 2.5 ml / g, 2.1 ml / g, 1.7 ml / g or 2.6 ml / g; (10) The nucleophilic fluorinating agent is selected from one or more of diethylaminosulfur trifluoride, sulfur tetrafluoride, bis(2-methoxyethyl)aminosulfur trifluoride, (diethylamino)difluorosulfonium tetrafluoroborate, 4-tert-butyl-2,6-dimethylphenylsulfur trifluoride, 2-chloro-1,3-bis(2,6-diisopropylphenyl)-1H-imidazolium chloride-cesium fluoride and hydrogen fluoride-pyridine complex; (11) The electrophilic fluorinating agent is selected from one or more of N-fluorobisbenzenesulfonamide, N-fluorobisbenzenesulfonamide, N-fluoropyridine trifluoromethanesulfonate and 1-fluoro-4-methyl-1,4-diazabicyclo[2.2.2]octanetetrafluoroborate; (12) The molar ratio of the fluorinating agent to the compound of formula II is 1:1 or 4:1; and (13) The reaction temperature of the oxidative fluorination reaction is 20-30℃.

8. The method for preparing the compound of formula I as described in claim 7, characterized in that, It meets one or more of the following conditions: (1) The amide solvent is N,N-dimethylformamide; (2) The ether solvent is tetrahydrofuran; (3) The nucleophilic fluorinating agent is diethylaminosulfur trifluoride; and (4) The electrophilic fluorinating agent is N-fluorobisbenzenesulfonamide, N-fluorobisbenzenesulfonamide or 1-fluoro-4-methyl-1,4-diazabicyclo[2.2.2]octanetetrafluoroborate.

9. The method for preparing the compound of formula I as described in claim 5, characterized in that, The compound of formula II was prepared by the following steps: in an organic solvent, in the presence of a sulfinizing dehalogenating agent, the compound of formula III underwent the sulfinizing dehalogenating reaction as shown below to obtain the compound of formula II; ； The conditions and operation of the sulfonation dehalogenation reaction are as described in any one of claims 1-4.

10. A compound of formula II; ； in, n and M are as described in any one of claims 1-8.

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