Method for enamine pentafluorosulfenyl by using sulfur hexafluoride as pentafluorosulfenyl source

Abstract

The invention discloses an enamine pentafluorosulfhydrylation method using sulfur hexafluoride as a pentafluorosulfenyl source, which comprises the following steps: placing a photocatalyst and an alkaline additive in a reaction device, replacing air in the reaction device by using sulfur hexafluoride gas, adding enamine substances and a solvent in the atmosphere of the sulfur hexafluoride gas, and reacting at the temperature of 60-80 DEG C for 1-2 hours to obtain the enamine pentafluorosulfhydrylation product. Sealing the reaction device, carrying out photocatalytic reaction under a light source with the wavelength of 380-400nm, and then adding hydrochloric acid to obtain the pentafluorosulfenyl product. According to the method, the sulfur hexafluoride is used as a safe and cheap pentafluorosulfenyl reagent and acts with specific enamine substances to prepare the high-added-value organic pentafluorosulfenyl group-containing small molecules, the sulfur hexafluoride is ingeniously used as a fluorination reagent in the method, so that the pentafluorosulfenyl reaction is safely, economically and mildly carried out, and the yield of the pentafluorosulfenyl group-containing small molecules is improved. Meanwhile, wide substrate compatibility is shown, so that a green and efficient new way is provided for chemical synthesis in the field.

Description

Technical Field

[0001] The invention relates to the technical field of organic chemical synthesis, and in particular to a method for pentafluorosulfurization of enamines using sulfur hexafluoride as a pentafluorosulfur source. Background Art

[0002] The pentafluorosulfonyl group structure is a unique octahedral structure around the sulfur atom. Due to its large steric hindrance and high chemical stability, it has broad development potential in the field of optoelectronic materials. In addition, the pentafluorosulfonyl group has more significant lipophilicity and electron-withdrawing properties than the trifluoromethyl group, which is of great significance for the synthesis and development of fluorine-containing drugs. The methods for synthesizing small molecules containing pentafluorosulfonyl groups are currently relatively limited, mainly limited to pentafluorosulfonylating agents or photoredox methods.

[0003] In 2018, Hans-Achim Wagenknech's group proposed the first photocatalytic redox method to convert it into pentafluorosulfonylated α-methylstyrene and α-phenylstyrene simply using light. This work addresses the challenge of precisely activating sulfur hexafluoride with a photoredox catalyst that designs a continuous electron transfer cycle that allows styrene to capture the generated pentafluorosulfonyl group. (ChemCatChem 2018, 10, 2955–2961)

[0004] In 2019, Hans-Achim Wagenknech's group described the use of SF6 as a pentafluorosulfonylating agent and a one-step photoredox method to prepare ether compounds with SF5 as an ortho-substituent. (Angew.Chem.Int.Ed.2020,59,300–303)

[0005] In 2021, Hans-Achim Wagenknech's group reported a one-step synthesis of perfluorosulfonylated oxygen-containing heterocyclic compounds from α-substituted olefins, and the proposed mechanism was supported by theoretical calculations, which not only provided insights in the pentafluorosulfonylation step, but also fully complied with Baldwin's cyclization rules. The synthesized oxygen heterocyclic compounds cannot be simply prepared by other synthetic methods, and their structural complexity is relatively high, which greatly expands the scope of pentafluorosulfonylated building blocks and has important application value in medicine and materials chemistry. (Chem.Eur.J.2021,27,8088–8093)

[0006] In 2021, Qing Fengling's research group developed a new synthesis method for SF5Cl, realized the free radical addition reaction of SF5Cl with diazo compounds, and successfully synthesized a series of α-SF5 carbonyl compounds and dehydroepiandrosterone derivatives. (Angew.Chem.Int.Ed.2021,60,15271–15275)

[0007] In the prior art, when synthesizing a series of pentafluorosulfonated derivatives, traditional conversion strategies are often limited by the need to pre-prepare expensive fluorination reagents and the reliance on highly toxic substances. These problems not only increase costs but also pose safety risks. Summary of the invention

[0008] The technical problem to be solved by the present invention is how to make enamine pentafluorosulfurization safe and at low cost.

[0009] The present invention solves the above technical problems through the following technical means:

[0010] A method for pentafluorosulfurization of enamines using sulfur hexafluoride as a pentafluorosulfur source comprises the following steps: placing a photocatalyst and an alkaline additive in a reaction device, replacing the air in the reaction device with sulfur hexafluoride gas, adding enamine substances and solvents under the sulfur hexafluoride gas atmosphere, sealing the reaction device, performing a photocatalytic reaction under a light source with a wavelength of 380-400nm, and then adding hydrochloric acid to obtain a pentafluorosulfurization product;

[0011] The solvent is a mixture of solvent A and solvent B, the solvent A is a mixture of one or more of ethyl acetate, dichloroethane, acetonitrile, dichloromethane, toluene, dioxane, 2-methyltetrahydrofuran, tetrahydrofuran, cyclopentyl methyl ether, and methyl tert-butyl ether, and the solvent B is methanol; the enamine substance is one of 1-(1-phenylvinyl)pyrrolidin-2-one, 1-(1-(m-tolyl)vinyl)pyrrolidin-2-one, and 1-(1-(3-fluorophenyl)vinyl)pyrrolidin-2-one.

[0012] Preferably, the photocatalyst is 10-phenylphenothiazine.

[0013] Preferably, the alkaline additive is tetrabutylammonium chloride, tetrabutylammonium iodide or a mixture of the two.

[0014] Preferably, the molar ratio of the photocatalyst to the enamine substance is 0.2:1.

[0015] Preferably, the molar ratio of the enamine substance to the alkaline additive is 1:0.7.

[0016] Preferably, the volume ratio of solvent A to solvent B is 1:0.6.

[0017] Preferably, the usage ratio of the enamine substance to the solvent is 0.1 mmol:1.6 ml.

[0018] Preferably, the volume of the added hydrochloric acid is 0.5 times the volume of solvent A.

[0019] Preferably, during the photocatalytic reaction, the power of the light source is 10 W, the temperature is 20° C., and the time is 24 h.

[0020] Preferably, the hydrochloric acid is dilute hydrochloric acid.

[0021] The present invention also proposes an application of sulfur hexafluoride as a pentafluorosulfonyl source for an enamine pentafluorosulfonation reaction, wherein the enamine substance is one of 1-(1-phenylvinyl)pyrrolidin-2-one, 1-(1-(m-tolyl)vinyl)pyrrolidin-2-one, and 1-(1-(3-fluorophenyl)vinyl)pyrrolidin-2-one.

[0022] Preferably, in a specific application process, the photocatalyst and the alkaline additive are placed in a reaction device, the air in the reaction device is replaced by sulfur hexafluoride gas, an enamine substance and a solvent are added under the sulfur hexafluoride gas atmosphere, the reaction device is sealed, a photocatalytic reaction is carried out under a light source with a wavelength of 380-400nm, and then hydrochloric acid is added to obtain a pentafluorosulfurization product;

[0023] The solvent is a mixture of solvent A and solvent B, wherein solvent A is a mixture of one or more of ethyl acetate, dichloroethane, acetonitrile, dichloromethane, toluene, dioxane, 2-methyltetrahydrofuran, tetrahydrofuran, cyclopentyl methyl ether, and methyl tert-butyl ether, and solvent B is methanol.

[0024] The advantages of the present invention are:

[0025] The present invention specifically relates to a method for preparing high value-added organic pentafluorosulfur group-containing small molecules by using sulfur hexafluoride as a safe and cheap pentafluorosulfurization reagent to react with specific enamine substances.

[0026] When synthesizing a series of pentafluorosulfylated derivatives, traditional conversion strategies are often limited by the need to pre-prepare expensive fluorination reagents and the reliance on highly toxic substances. These problems not only drive up costs but also pose safety risks. To this end, the present invention proposes an innovative method that cleverly uses sulfur hexafluoride as a fluorination reagent to achieve safe, economical, and mild pentafluorosulfylated reactions while showing a wide range of substrate compatibility, thereby providing a greener and more efficient new approach for chemical synthesis in this field. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is the H NMR spectrum of the product in Example 11 of the present invention;

[0028] Figure 2 is the NMR carbon spectrum of the product in Example 11 of the present invention;

[0029] Figure 3is the NMR fluorine spectrum of the product in Example 11 of the present invention;

[0030] Figure 4 is the H NMR spectrum of the product in Example 12 of the present invention;

[0031] Figure 5 is the NMR carbon spectrum of the product in Example 12 of the present invention;

[0032] Figure 6 This is the NMR fluorine spectrum of the product in Example 12 of the present invention. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Unless otherwise specified, the test materials and reagents used in the following examples can be obtained from commercial sources.

[0035] If no specific techniques or conditions are specified in the examples, they can be carried out according to the techniques or conditions described in the literature in the art or according to the product instructions.

[0036] Example 1

[0037] A method for pentafluorosulfurization of enamines using sulfur hexafluoride as a pentafluorosulfur source, the reaction equation is as follows:

[0038] in,

[0039] R is H.

[0040] The following steps are involved:

[0041] (1) Preparation of photocatalyst solution: Place an A615 polytetrafluoroethylene magnetic stirrer in a Schlenk tube with a volume of 10 mL, then weigh 0.2 eq (5.5 mg) of the photocatalyst PTH 10-phenylphenothiazine and 0.7 eq (19 mg) of the additive TBAC and add them to the Schlenk tube. Screw on the polytetrafluoroethylene stopcock to seal the tube mouth and connect the tube cavity with the branch tube mouth. Take a high vacuum three-way gas valve with a stopper, and connect its interfaces to the Schlenk tube, vacuum pump and sulfur hexafluoride gas respectively. Connect the Schlenk tube and the vacuum pump, and extract the air in the tube (for more than 3 seconds); connect the sulfur hexafluoride gas and the Schlenk tube, and add sulfur hexafluoride gas (for more than 3 seconds). One set of extraction and degassing is a ventilation cycle. Repeat the ventilation 3 times and stay in the degassing state so that there is a positive pressure of pure sulfur hexafluoride gas in the tube. Place the Schlenk tube at -78°C, open the stopcock of the Schlenk tube, quickly add 1eq (18.7mg) of the raw material 1-(1-phenylvinyl)pyrrolidin-2-one, 1ml of the solvent ethyl acetate and 0.6ml of the solvent methanol in the atmosphere of sulfur hexafluoride gas, close the stopcock, and keep the Schlenk tube connected to the sulfur hexafluoride gas for 30 seconds. Close the stopcock to completely seal the lumen of the Schlenk tube, and disconnect the vacuum pump and the sulfur hexafluoride gas.

[0042] (2) Reaction conditions: Place a sealed Schlenk tube in a parallel light reactor, adjust the light source wavelength to 380-400 nm, power to 10 W, and temperature to 20°C, and react for 24 h.

[0043] (3) Reaction treatment: Open the Schlenk tube, wait until the bubbles disappear completely, and then add 0.5 ml of HCl.

[0044] (4) Reaction results: 65% isolation yield ( 19 F-NMR corrected yield 75%) to obtain the substrate 12-(pentafluoro-λ 6 -sulfaneyl)-1-phenylethan-1-one, 2-(pentafluoro-λ 6 -sulfonyl)-1-phenylethane-1-one, its NMR data are as follows:

[0045] 1 H NMR (400MHz, Chloroform-d) δ8.04–7.96(m,2H),7.71–7.61(m,1H),7.61–7.49(m,2H),4.88(p,J=7.8Hz,2H).

[0046] 19F NMR(376MHz,Chloroform-d)δ81.93–80.08(m,1F),72.93–72.33(m,4F).

[0047] Example 2

[0048] A method for pentafluorosulfurization of enamines using sulfur hexafluoride as a pentafluorosulfur source comprises the following steps:

[0049] (1) Preparation of photocatalyst solution: Place an A615 polytetrafluoroethylene magnetic stirrer in a Schlenk tube with a volume of 10 mL, then weigh 0.2 eq (5.5 mg) of the photocatalyst PTH 10-phenylphenothiazine and 0.7 eq (19 mg) of the additive TBAC and add them to the Schlenk tube. Screw on the polytetrafluoroethylene stopcock to seal the tube mouth and connect the tube cavity with the branch tube mouth. Take a high vacuum three-way gas valve with a stopper, and connect its interfaces to the Schlenk tube, vacuum pump and sulfur hexafluoride gas respectively. Connect the Schlenk tube and the vacuum pump, and extract the air in the tube (for more than 3 seconds); connect the sulfur hexafluoride gas and the Schlenk tube, and add sulfur hexafluoride gas (for more than 3 seconds). One set of extraction and degassing is a ventilation cycle. Repeat the ventilation 3 times and stay in the degassing state so that there is a positive pressure of pure sulfur hexafluoride gas in the tube. Place the Schlenk tube at -78°C, open the stopcock of the Schlenk tube, quickly add the raw material 1-(1-phenylvinyl)pyrrolidin-2-one 1eq (18.7mg), solvent DCE 1ml and solvent methanol 0.6ml in the sulfur hexafluoride gas atmosphere, close the stopcock, keep the Schlenk tube connected to the sulfur hexafluoride gas for 30 seconds, close the stopcock to completely seal the Schlenk tube lumen, and disconnect the vacuum pump and sulfur hexafluoride gas.

[0050] (2) Reaction conditions: Place a sealed Schlenk tube in a parallel light reactor, adjust the light source wavelength to 380-400 nm, power to 10 W, and temperature to 20°C, and react for 24 h.

[0051] (3) Reaction treatment: Open the Schlenk tube, wait until the bubbles disappear completely, and then add 0.5 ml of HCl.

[0052] (4) Reaction results: 56% isolation yield ( 19 F-NMR corrected yield 59%) to obtain the substrate 12-(pentafluoro-λ 6 -sulfaneyl)-1-phenylethan-1-one, 2-(pentafluoro-λ 6 -sulfonyl)-1-phenylethan-1-one.

[0053] Example 3

[0054] A method for pentafluorosulfuration of enamines using sulfur hexafluoride as a pentafluorosulfur source, wherein the steps thereof are different from those of Example 2 only in that: in (1), acetonitrile is used instead of the solvent DCE in Example 2, and the remaining steps are the same as those of Example 2.

[0055] Reaction results: 59% isolation yield ( 19 F-NMR corrected yield 62%) to obtain the substrate 12-(pentafluoro-λ 6 -sulfaneyl)-1-phenylethan-1-one, 2-(pentafluoro-λ 6 -sulfonyl)-1-phenylethan-1-one.

[0056] Example 4

[0057] A method for pentafluorosulfuration of enamines using sulfur hexafluoride as a pentafluorosulfur source, wherein the steps thereof are different from those of Example 2 only in that: in (1), DCM is used instead of the solvent DCE in Example 2, and the remaining steps are the same as those of Example 2.

[0058] Reaction results: 46% isolation yield ( 19 F-NMR corrected yield 55%) to obtain the substrate 12-(pentafluoro-λ 6 -sulfaneyl)-1-phenylethan-1-one, 2-(pentafluoro-λ 6 -sulfonyl)-1-phenylethan-1-one.

[0059] Example 5

[0060] A method for pentafluorosulfuration of enamines using sulfur hexafluoride as a pentafluorosulfur source, wherein the steps thereof are different from those of Example 2 only in that: in (1), toluene is used instead of the solvent DCE in Example 2, and the remaining steps are the same as those of Example 2.

[0061] Reaction results: 58% isolation yield ( 19 F-NMR corrected yield 61%) to obtain the substrate 12-(pentafluoro-λ 6 -sulfaneyl)-1-phenylethan-1-one, 2-(pentafluoro-λ 6 -sulfonyl)-1-phenylethan-1-one.

[0062] Example 6

[0063] A method for pentafluorosulfurization of enamines using sulfur hexafluoride as a pentafluorosulfur source, wherein the steps thereof are different from those of Example 2 only in that: in (1), dioxane is used instead of the solvent DCE in Example 2, and the remaining steps are the same as those of Example 2.

[0064] Reaction results: 58% isolation yield ( 19 F-NMR corrected yield 61%) to obtain the substrate 12-(pentafluoro-λ 6 -sulfaneyl)-1-phenylethan-1-one, 2-(pentafluoro-λ 6 -sulfonyl)-1-phenylethan-1-one.

[0065] Example 7

[0066] A method for pentafluorosulfuration of enamines using sulfur hexafluoride as a pentafluorosulfur source, wherein the steps thereof are different from those of Example 2 only in that: in (1), 2-methyltetrahydrofuran is used instead of the solvent DCE in Example 2, and the remaining steps are the same as those of Example 2.

[0067] Reaction results: 32% isolation yield ( 19 F-NMR corrected yield 35%) to obtain the substrate 12-(pentafluoro-λ 6 -sulfaneyl)-1-phenylethan-1-one, 2-(pentafluoro-λ 6 -sulfonyl)-1-phenylethan-1-one.

[0068] Example 8

[0069] A method for pentafluorosulfuration of enamines using sulfur hexafluoride as a pentafluorosulfur source, wherein the steps thereof are different from those of Example 2 only in that in (1), tetrahydrofuran (THF) is used instead of the solvent DCE in Example 2, and the remaining steps are the same as those of Example 2.

[0070] Reaction results: 55% isolation yield ( 19 F-NMR corrected yield 59%) to obtain the substrate 12-(pentafluoro-λ 6 -sulfaneyl)-1-phenylethan-1-one, 2-(pentafluoro-λ 6 -sulfonyl)-1-phenylethan-1-one.

[0071] Example 9

[0072] A method for pentafluorosulfuration of enamines using sulfur hexafluoride as a pentafluorosulfur source, wherein the steps thereof are different from those of Example 2 only in that: in (1), CPME is used instead of the solvent DCE in Example 2, and the remaining steps are the same as those of Example 2.

[0073] Reaction results: 46% isolation yield ( 19 F-NMR corrected yield 53%) to obtain the substrate 12-(pentafluoro-λ 6-sulfaneyl)-1-phenylethan-1-one, 2-(pentafluoro-λ 6 -sulfonyl)-1-phenylethan-1-one.

[0074] Example 10

[0075] A method for pentafluorosulfuration of enamines using sulfur hexafluoride as a pentafluorosulfur source, wherein the steps thereof are different from those of Example 2 only in that: in (1), the solvent MTBE is used instead of the solvent DCE in Example 2, and the remaining steps are the same as those of Example 2.

[0076] Reaction results: 58% isolation yield ( 19 F-NMR corrected yield 67%) to obtain the substrate 12-(pentafluoro-λ 6 -sulfaneyl)-1-phenylethan-1-one, 2-(pentafluoro-λ 6 -sulfonyl)-1-phenylethan-1-one.

[0077] Comparative Example 1

[0078] The only difference from Example 2 is that in (1), DMSO is used instead of the solvent DCE in Example 2, and the remaining steps are the same as Example 2.

[0079] Reaction results: Substrate 1, only trace amounts of fluorine were obtained.

[0080] Embodiment 11

[0081] Reaction system substrate expansion: 2-(pentafluoro-λ 6 -sulfaneyl)-1-(m-tolyl)ethan-1-one i.e. 2-(pentafluoro-λ 6 -sulfonyl)-1-(m-tolyl)ethan-1-one

[0082] A method for pentafluorosulfurization of enamines using sulfur hexafluoride as a pentafluorosulfur source, wherein the steps thereof are different from those of Example 2 only in that: in (1), 20.1 mg of the raw material 1-(1-(m-tolyl)vinyl)pyrrolidin-2-one, i.e., 1-(1-(m-tolyl)vinyl)pyrrolidin-2-one is used instead of 18.7 mg of the raw material 1-(1-phenylvinyl)pyrrolidin-2-one in Example 2, and the solvent EA is used instead of the solvent DCE therein, and the remaining steps are the same as those of Example 2.

[0083] Reaction results: The substrate 22-(pentafluoro-λ 6-sulfaneyl)-1-(m-tolyl)ethan-1-one i.e. 2-(pentafluoro-λ 6 -sulfonyl)-1-(m-tolyl)ethane-1-one. The NMR spectrum of the product is as follows Figure 1-3 The data is shown below:

[0084] 1 H NMR (500MHz, Chloroform-d) δ7.88–7.76 (m, 2H), 7.50–7.37 (m, 2H), 4.86 (p, J = 7.8Hz, 2H), 2.44 (s, 3H).

[0085] 13 C NMR (126MHz, Chloroform-d) δ 187.45–187.28 (m), 139.22, 135.66, 135.47, 129.71, 129.06, 126.56, 71.85 (p, J = 12.9Hz), 21.47.

[0086] 19 F NMR(471MHz,Chloroform-d)δ81.96–80.35(m,1F),72.87–72.24(m,4F).

[0087] Example 12

[0088] Reaction system substrate expansion: 1-(3-fluorophenyl)-2-(pentafluoro-λ 6 -sulfaneyl)ethan-1-one, namely 1-(3-fluorophenyl)-2-(pentafluoro-λ 6 -sulfonyl)vinyl-1-one

[0089] A method for pentafluorosulfonation of enamines using sulfur hexafluoride as a pentafluorosulfonyl source, wherein the steps thereof are different from those of Example 2 only in that: in (1), 20.5 mg of the raw material 1-(1-(3-fluorophenyl)vinyl)pyrrolidin-2-one, i.e., 1-(1-(3-fluorophenyl)vinyl)pyrrolidin-2-one is used instead of 18.7 mg of the raw material 1-(1-phenylvinyl)pyrrolidin-2-one in Example 2, and the solvent EA is used instead of the solvent DCE therein, and the remaining steps are the same as those of Example 2.

[0090] Reaction results: 40% isolation yield, the substrate 31-(3-fluorophenyl)-2-(pentafluoro-λ 6-sulfaneyl)ethan-1-one, namely 1-(3-fluorophenyl)-2-(pentafluoro-λ 6 -sulfonyl)vinyl-1-one. The NMR spectrum of the product is as follows Figure 4-6 The data is shown below:

[0091] 1 H NMR (600MHz, Chloroform-d) δ7.79(d,J=7.8Hz,1H),7.69(dt,J=9.3,2.1Hz,1H),7.59–7.50(m,1H),7.37(td,J=8.0,2.4Hz,1H),4.86(p,J=7.8Hz,2H).

[0092] 13 C NMR(151MHz,Chloroform-d)δ186.12,163.09(d,J=249.4Hz),137.50(d,J=8.2Hz),130.98( d,J=8.3Hz), 125.07(d), 121.85(d,J=21.7Hz), 115.94(d,J=23.2Hz), 71.78(p,J=14.6Hz).

[0093] 19 F NMR(565MHz,Chloroform-d)δ81.34–80.00(m,1F),73.10–72.75(m,4F),

[0094] -109.21–-112.09(m,1F).

[0095] Comparative Example 2

[0096] The steps are different from those of Example 2 only in that: in (1), the solvent N,N-dimethylformamide is used instead of the solvent DCE, and the remaining steps are the same as those of Example 2.

[0097] Reaction results: Only trace amounts of product were observed.

[0098] Comparative Example 3

[0099] The steps are different from those of Example 2 only in that: in (1), a light source of 365 nm is used instead of a light source of 380-400 nm, and the remaining steps are the same as those of Example 2.

[0100] Reaction results: Only trace amounts of product were observed.

[0101] Comparative Example 4

[0102] Compared with the synthesis method and catalytic method of Qing Fengling's research group, this article (Angew. Chem. Int. Ed. 2021, 60, 15271–15275) uses α-diazocarbonyl compounds and pentafluorosulfuryl chloride reagents to construct pentafluorosulfur compounds.

[0103] (1) Operation steps: In a glove box environment, first add K3PO4 (31.8 mg, 0.15 mmol) to a 4 mL vial equipped with a magnetic stirring bar, then the vial is tightly sealed and taken out of the glove box. Next, DCM (1 mL) and SF5Cl (0.15 M in n-hexane, 1 mL, 0.15 mmol) are added to the vial at room temperature. Subsequently, the α-diazocarbonyl compound (0.1 mmol) is dissolved in DCM (1 mL) and quickly added to the above reaction mixture. The entire reaction system is stirred continuously for 3 hours under magnetic stirring. Once the reaction is completed, the air in the vial must be carefully expelled using a needle to prevent the introduction of impurities. Afterwards, the solvent is evaporated under reduced pressure to complete the initial post-reaction processing steps.

[0104] (2) Comparison: The fluorination reagents of the present invention are all sulfur hexafluoride, which is low in price, suitable for a variety of substrates, and the solvent ethyl acetate is easy to separate. The α-diazocarbonyl compound used in the comparative example requires multi-step synthesis, and a large amount of toxic reagents and low temperatures of 0°C and -78°C are used in the synthesis process. The preparation is cumbersome, costly, and time-consuming. In addition, the reagent also needs to be stored under nitrogen conditions, and the storage conditions are relatively harsh, which is not conducive to application.

[0105]

[0106]

[0107] Comparative Example 5

[0108] Reaction system substrate expansion: 1-(4-methoxyphenyl)-2-(pentafluoro-λ 6 -sulfaneyl)ethan-1-one, namely 1-(4-methoxyphenyl)-2-(pentafluoro-λ 6 -sulfonyl)vinyl-1-one

[0109] The steps are different from those in Example 2 only in that in (1), 21.7 mg of the raw material 1-(1-(4-methoxyphenyl)vinyl)pyrrolidin-2-one, i.e., 1-(1-(4-methoxyphenyl)vinyl)pyrrolidin-2-one is used instead of 18.7 mg of the raw material 1-(1-phenylvinyl)pyrrolidin-2-one, and the remaining steps are the same as in Example 2.

[0110] Reaction results: Under TLC monitoring, only trace amounts of products were observed.

[0111] Comparative Example 6

[0112] The steps are different from those of Example 2 only in that in (1), 0.6 ml of isopropanol is used instead of 0.6 ml of methanol, and the remaining steps are the same as those of Example 2.

[0113] Reaction result: No target product was obtained.

[0114] Embodiment 13

[0115] The steps are different from those of Example 2 only in that: in (1), the additive TBAI is used in an amount equimolar to TBAC instead of the additive TBAC, and the remaining steps are the same as those of Example 2.

[0116] Reaction results: 36% isolation yield ( 19 F-NMR corrected yield 25%) to obtain the substrate 12-(pentafluoro-λ 6 -sulfaneyl)-1-phenylethan-1-one, 2-(pentafluoro-λ 6 -sulfonyl)-1-phenylethan-1-one.

[0117] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for pentafluorosulfurization of enamines using sulfur hexafluoride as a pentafluorosulfur source, characterized in that: The method comprises the following steps: placing a photocatalyst and an alkaline additive in a reaction device, replacing the air in the reaction device with sulfur hexafluoride gas, adding enamine substances and solvents in the sulfur hexafluoride gas atmosphere, sealing the reaction device and performing a photocatalytic reaction under a light source with a wavelength of 380-400nm, and then adding hydrochloric acid to obtain a pentafluorosulfurization product; The solvent is a mixture of solvent A and solvent B, the solvent A is a mixture of one or more of ethyl acetate, dichloroethane, acetonitrile, dichloromethane, toluene, dioxane, 2-methyltetrahydrofuran, tetrahydrofuran, cyclopentyl methyl ether, and methyl tert-butyl ether, and the solvent B is methanol; the enamine substance is one of 1-(1-phenylvinyl)pyrrolidin-2-one, 1-(1-(m-tolyl)vinyl)pyrrolidin-2-one, and 1-(1-(3-fluorophenyl)vinyl)pyrrolidin-2-one.

2. The method for pentafluorosulfurization of enamines using sulfur hexafluoride as a pentafluorosulfur source according to claim 1, characterized in that: The photocatalyst is 10-phenylphenothiazine.

3. The method for pentafluorosulfurization of enamines using sulfur hexafluoride as a pentafluorosulfur source according to claim 1, characterized in that: The alkaline additive is one of tetrabutylammonium chloride and tetrabutylammonium iodide or a mixture of the two.

4. The method for pentafluorosulfurization of enamines using sulfur hexafluoride as a pentafluorosulfur source according to claim 1, characterized in that: The molar ratio of the photocatalyst to the enamine substance is 0.2:

1.

5. The method for pentafluorosulfurization of enamines using sulfur hexafluoride as a pentafluorosulfur source according to claim 1, characterized in that: The molar ratio of the enamine substance to the alkaline additive is 1:0.

7.

6. The method for pentafluorosulfurization of enamines using sulfur hexafluoride as a pentafluorosulfur source according to claim 1, characterized in that: The volume ratio of the solvent A to the solvent B is 1:0.

6.

7. The method for pentafluorosulfurization of enamines using sulfur hexafluoride as a pentafluorosulfur source according to claim 1, characterized in that: The usage ratio of the enamine substance to the solvent is 0.1 mmol:1.6 ml.

8. The method for pentafluorosulfurization of enamines using sulfur hexafluoride as a pentafluorosulfur source according to claim 1, characterized in that: The volume of hydrochloric acid added was 0.5 times the volume of solvent A.

9. The method for pentafluorosulfurization of enamines using sulfur hexafluoride as a pentafluorosulfur source according to any one of claims 1 to 8, characterized in that: During the photocatalytic reaction, the power of the light source is 10W, the temperature is 20°C, and the time is 24h.

10. Use of sulfur hexafluoride as a pentafluorosulfenyl source for pentafluorosulfenylation of enamines, characterized in that: The enamine substance is one of 1-(1-phenylvinyl)pyrrolidin-2-one, 1-(1-(m-tolyl)vinyl)pyrrolidin-2-one and 1-(1-(3-fluorophenyl)vinyl)pyrrolidin-2-one.

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