Method for preparing sulfoxide compounds as single enantiomers or in enantiomerically enriched form

Abstract

The present invention belongs to the field of organic chemical synthesis, and specifically relates to a method for preparing sulfoxide compounds as single enantiomers or in an enantiomerically enriched form. A catalyst used therein is as represented by formula I, wherein R1 is methyl or ethyl; and C* positions are chiral centers, both in the R configuration or the S configuration. The catalyst of the present invention exhibits an excellent effect in catalyzing the asymmetric oxidation of thioether compounds to prepare sulfoxide compounds as single enantiomers or in an enantiomerically enriched form, produces target compounds with a high purity and a high yield, and is applicable to industrial production.

Description

Preparation methods of single enantiomers or enantiomer-enriched sulfoxide compounds Technical Field

[0001] This invention belongs to the field of organic chemical synthesis, specifically relating to a method for preparing a single enantiomer or an enantiomer-enriched form of a sulfoxide compound. Background Technology

[0002] Weed control is a crucial aspect of achieving efficient agriculture. A wide variety of herbicides are available on the market. CN116803993A discloses a chiral arylformamide herbicide with excellent weeding effects due to its specific chiral structure. However, existing synthesis processes suffer from low enantioselectivity and low yield in the asymmetric oxidation step of thioethers. There is an urgent need to develop more suitable catalysts and methods for catalyzing the asymmetric oxidation of thioether compounds to prepare single enantiomers or enantiomer-enriched sulfoxide compounds. Summary of the Invention

[0003] To address the aforementioned problems in the prior art, this invention provides a method for preparing a single enantiomer or an enantiomer-enriched form of a sulfoxide compound.

[0004] The technical solution adopted in this invention is as follows:

[0005] This invention provides a catalyst, as shown in Formula I”:

[0006] Wherein, R1 is methyl or ethyl; C * The chiral center is located at the position, and all of them are either R-configured or S-configured. Based on the content of stereoisomers with R and S configurations at the position, they have a stereochemical purity of 50.5-100% (R) or (S), preferably 60-100% (R) or (S), more preferably 80-100% (R) or (S), further preferably 90-100% (R) or (S), and even more preferably 95-100% (R) or (S).

[0007] The present invention also provides a method for preparing the catalyst, which is derived from ligand compound IV. It is prepared by complexation with titanium reagent.

[0008] In one specific embodiment, the titanium reagent is selected from at least one of methyl titanate, ethyl titanate, isopropyl titanate, n-butyl titanate, or titanium tetrachloride.

[0009] In one embodiment, the reaction is carried out in the presence of a solvent; preferably, the solvent is selected from at least one of dichloromethane, dichloroethane, methanol, ethanol, isopropanol, n-butanol, toluene, xylene, or chloroform.

[0010] In one specific embodiment, compound IV is prepared by reacting compound V and compound VI, as shown in the following reaction formula:

[0011] In another specific embodiment, the reaction is carried out in the presence of a solvent; preferably, the solvent is selected from at least one of dichloromethane, dichloroethane, methanol, ethanol, isopropanol, n-butanol, toluene, xylene, or chloroform.

[0012] The present invention also provides the application of the catalyst in the asymmetric oxidation of thioether compounds to prepare sulfoxide compounds in the form of a single enantiomer or enantiomer-enriched forms.

[0013] In one specific embodiment, the thioether compound is The sulfoxide compounds

[0014] Wherein, X represents C1-C6 alkyl;

[0015] Q represents C1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, or C1-C6 alkyl, C2-C6 alkenyl, or C2-C6 alkynyl substituted with at least one group selected from halogen, cyano, hydroxyl, amino, C1-C6 alkoxy, C1-C6 alkylthio, or C3-C6 cycloalkyl.

[0016] Z1 represents C1-C6 alkoxy, halogen, C1-C6 alkylthio, C1-C6 alkylsulfoxide, C1-C6 alkylsulfonyl, or C1-C6 alkoxy-C1-C6 alkyl.

[0017] Z2 represents a halogenated C1-C6 alkyl group.

[0018] In another specific embodiment, X represents methyl;

[0019] Q represents methyl, ethyl, propyl, butyl, trifluoromethyl, Methoxyethyl, methylthioethyl, or cyclopropylmethyl;

[0020] Z1 represents fluorine, chlorine, methoxy, ethoxy, methylthio, ethylthio, butylthio, methyl sulfoxide, methyl sulfonyl, or methoxymethyl;

[0021] Z2 represents CF3 or CHF2.

[0022] In another specific embodiment, the enantiomer ratio is 50.5:49.5 to 100:0 (R):(S) or (S):(R), preferably 60:40 to 100:0 (R):(S) or (S):(R), more preferably 80:20 to 100:0 (R):(S) or (S):(R), further preferably 90:10 to 100:0 (R):(S) or (S):(R), and even more preferably 95:5 to 100:0 (R):(S) or (S):(R).

[0023] This invention also provides a method for preparing a single enantiomer or an enantiomer-enriched form of a sulfoxide compound, comprising the following steps:

[0024] Compound II is oxidized in the presence of catalyst I and an oxidant to give compound III, as shown in the following reaction equation:

[0025] S* is the chiral center.

[0026] X represents C1-C6 alkyl;

[0027] Q represents C1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, or C1-C6 alkyl, C2-C6 alkenyl, or C2-C6 alkynyl substituted with at least one group selected from halogen, cyano, hydroxyl, amino, C1-C6 alkoxy, C1-C6 alkylthio, or C3-C6 cycloalkyl.

[0028] Z1 represents C1-C6 alkoxy, halogen, C1-C6 alkylthio, C1-C6 alkylsulfoxide, C1-C6 alkylsulfonyl, or C1-C6 alkoxy-C1-C6 alkyl.

[0029] Z2 represents a halogenated C1-C6 alkyl group.

[0030] In one specific embodiment, X represents methyl;

[0031] Q represents methyl, ethyl, propyl, butyl, trifluoromethyl, Methoxyethyl, methylthioethyl, or cyclopropylmethyl;

[0032] Z1 represents fluorine, chlorine, methoxy, ethoxy, methylthio, ethylthio, butylthio, methyl sulfoxide, methyl sulfonyl, or methoxymethyl;

[0033] Z2 represents CF3 or CHF 2。

[0034] In the definitions of compounds shown in the above general formulas and in all the following structural formulas, the technical terms used, whether alone or in compound terms, represent the following substituents: alkyl groups having more than two carbon atoms can be straight-chain or branched. For example, in the compound term "alkoxyalkyl," the alkyl group can be -CH2-, -CH2CH2-, -CH(CH3)-, -C(CH3)2-, etc. The alkyl group is, for example, C1 alkyl-methyl; C2 alkyl-ethyl; C3 alkyl-propyl such as n-propyl or isopropyl; C4 alkyl-butyl such as n-butyl, isobutyl, tert-butyl, or 2-butyl; C5 alkyl-pentyl such as n-pentyl; C6 alkyl-hexyl such as n-hexyl, isohexyl, and 1,3-dimethylbutyl. Similarly, alkenyl groups are, for example, vinyl, allyl, 1-methylprop-2-en-1-yl, 2-methylprop-2-en-1-yl, but-2-en-1-yl, but-3-en-1-yl, 1-methylbut-3-en-1-yl, and 1-methylbut-2-en-1-yl. Alkynyl groups are, for example, ethynyl, propargyl, but-2-yn-1-yl, but-3-yn-1-yl, and 1-methylbut-3-yn-1-yl. Multiple bonds can be present at any position in each unsaturated group. Cycloalkyl groups are saturated carbocyclic ring systems having, for example, three to six carbon atoms, such as cyclopropyl, cyclobutyl, cyclopentyl, or cyclohexyl. Halogens are fluorine, chlorine, bromine, or iodine.

[0035] If a group is substituted by another group, this should be understood to mean that the group is substituted by one or more (e.g., 2, 3, 4, or 5) identical or different groups selected from those mentioned groups. Furthermore, the scope of the claims excludes compounds that are chemically unstable under standard conditions, as known to those skilled in the art.

[0036] In one embodiment, the oxidant is selected from at least one of hydrogen peroxide, tert-butanol peroxide, or cumene hydroperoxide.

[0037] In one specific embodiment, the reaction is carried out in the presence of a solvent; preferably, the solvent is selected from at least one of dichloromethane, dichloroethane, chloroform, alcohols (such as methanol, ethanol, isopropanol, n-butanol, n-octanol, isooctanol, etc.), acetonitrile, DMF, DMSO, dioxane, or ethyl acetate.

[0038] In one specific embodiment, the molar ratio of catalyst I to compound II is 0.01 to 0.2:1, and / or the molar ratio of oxidant to compound II is 1 to 2:1; preferably, the molar ratio of catalyst I to compound II is 0.05 to 0.1:1.

[0039] In one specific embodiment, the reaction temperature is 0–50°C.

[0040] In one specific embodiment, the enantiomer ratio is 50.5:49.5 to 100:0 (R):(S) or (S):(R), preferably 60:40 to 100:0 (R):(S) or (S):(R), more preferably 80:20 to 100:0 (R):(S) or (S):(R), further preferably 90:10 to 100:0 (R):(S) or (S):(R), and even more preferably 95:5 to 100:0 (R):(S) or (S):(R).

[0041] The catalyst described in this invention exhibits excellent performance in the asymmetric oxidation of sulfoxide compounds to prepare single enantiomers or enantiomer-enriched forms of sulfoxide compounds. The target compounds have high purity and high yield, making them suitable for industrial production. Detailed Implementation

[0042] The following examples are for illustrative purposes only and should not be construed as limiting the invention in any way. The scope of protection of this invention is defined by the claims.

[0043] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0044] Example 1

[0045] (1) Preparation of catalyst I-1:

[0046] 182 g of dichloromethane, 26 g of V-1, and 23.9 g of VI were added sequentially to a 1 L reaction flask, and the reaction was carried out at room temperature for 1 hour. After the reaction was complete, 30.5 g of isopropyl titanate was added dropwise to the system. One hour after the addition was completed, a solution of catalyst I-1 was obtained. During the desolvation process under reduced pressure, a solid precipitated, which was filtered and dried at 40 °C for 5 hours to obtain 46.1 g of pure yellow powdered catalyst I-1, with a yield of 90% and a purity of 97%. ESI-MS analysis of the product showed m / z = 587.4 [M+H]. + NMR data: 1 H NMR (CDCl3, 300MHz): δ (ppm): 3.70 (s, 4H), 3.79 (s, 6H,) 5.46-5.49 (t, 2H), 6.82-6.95 (m, 6H), 7.36-7.49 (m, 10H), 8.31 (2H, s).

[0047] The reaction equation is as follows:

[0048] (2) Preparation of compound III-1:

[0049] II-1 (20 g, 0.055 mol, 1.0 eq) was dissolved in dichloromethane solvent (282 g), and chiral titanium complex catalyst I-1 (1.8 g, 0.00275 mol, 0.05 eq) was added at room temperature. The temperature was maintained at 35–40 °C. 30% hydrogen peroxide (9.36 g, 0.0825 mol, 1.5 eq) was added dropwise to the mixture. After reacting at this temperature for 4.5 hours, 15% sodium sulfite solution (24 g, 0.0286 mol, 0.52 eq) was added until the KI-starch test paper showed no color change. After quenching, the mixture was allowed to stand and separated. The oil phase was dried with anhydrous Na2SO4. The product was purified by column chromatography (petroleum ether: ethyl acetate = 4:1). The yield of this oxidation reaction was calculated to be 95.6%, and the purity was 96.3%. The R and S configurations of compound III-1 were separated using a chiral liquid chromatography column. The ee value was calculated based on the peak area to be 89%. The formula for calculating the ee value is: (RS) / (R+S)*100%. All subsequent calculations of the ee value follow this formula.

[0050] The reaction formula is as follows:

[0051] Example 2

[0052] Compound III-1 was obtained by reacting with 0.1 eq of catalyst I-1 according to step (2) in Example 1, with a yield of 96.5%, purity of 96.6%, and ee value of 92%.

[0053] Example 3

[0054] By replacing the raw materials in the above examples with the compounds listed in Table 1 below, high-purity and high-yield target compounds were also obtained. Representative experimental results are as follows:

[0055] Table 1 Structural Formula of Raw Material II

[0056] (1) In a 500 ml reaction vessel, 300 g of dichloromethane was first added, followed by 20 g of II-1. The reaction solution was kept at a temperature of 35–40 °C. Then, 2.1 g of catalyst I-1 was added, and the reaction solution was kept at a controlled temperature. 10.1 g of 30% hydrogen peroxide was added dropwise over a period of 0.5 h. The reaction progress was monitored by HPLC. Then, the mixture was stirred with 36 ml of 10% sodium bisulfite aqueous solution. After phase separation, the aqueous phase was extracted with 200 ml of dichloromethane. The combined organic phases were concentrated (PE:EA = 3:1) and subjected to column chromatography. After distillation to remove ethyl acetate and petroleum ether, the mixture was slowly cooled with stirring. The precipitated solid compound III-11 was filtered out with an HPLC purity of 94%, a yield of 96%, and an ee of 90.2%.

[0057] The reaction formula is as follows:

[0058] (2) In a 500 ml reaction vessel, 300 g of dichloromethane was first added, followed by 20 g of II-12. The reaction solution was kept at a temperature of 35–40 °C. Then, 0 g of catalyst I-12 was added, and the reaction solution was kept at a controlled temperature. 9.7 g of 30% hydrogen peroxide was added dropwise over 0.5 h. The reaction progress was monitored by HPLC. Then, the mixture was stirred with 36 ml of 10% sodium bisulfite aqueous solution. After phase separation, the aqueous phase was extracted with 200 ml of dichloromethane. The combined organic phases were concentrated (PE:EA = 5:1) and subjected to column chromatography. After distillation to remove ethyl acetate and petroleum ether, the mixture was slowly cooled with stirring. The precipitated solid compound III-12 was filtered off, with an HPLC purity of 96%, a yield of 95%, and an optical purity of ee = 90.5%.

[0059] The reaction formula is as follows:

[0060] (3) In a 500 ml reaction vessel, 300 g of dichloromethane was first added, followed by 20 g of II-13. The reaction solution was kept at a temperature of 35–40 °C. Then, 1.86 g of catalyst I-1 was added, and the reaction solution was kept at a controlled temperature. 9.0 g of 30% hydrogen peroxide was added dropwise over 0.5 h. The reaction progress was monitored by HPLC. Then, the mixture was stirred with 36 ml of 10% sodium bisulfite aqueous solution. After phase separation, the aqueous phase was extracted with 200 ml of dichloromethane. The combined organic phases were concentrated (PE:EA = 5:1) and subjected to column chromatography. After distillation to remove ethyl acetate and petroleum ether, the mixture was slowly cooled with stirring. The precipitated solid compound III-13 was filtered out with an HPLC purity of 96%, a yield of 95%, and an optical purity of ee = 89.15%.

[0061] The reaction formula is as follows:

[0062] (4) In a 500 ml reaction vessel, first add 300 g of dichloromethane, then add 20 g of II-20. Maintain the reaction temperature at 35–40 °C, then add 1.86 g of catalyst I-1. Maintain the reaction temperature and add 9.0 g of 30% hydrogen peroxide dropwise over 0.5 h. Monitor the reaction progress by HPLC. Then stir with 36 ml of 10% sodium bisulfite aqueous solution. After phase separation, extract the aqueous phase with 200 ml of dichloromethane. Concentrate the combined organic phases (PE:EA = 3:1) and perform column chromatography. After distilling to remove ethyl acetate and petroleum ether, slowly cool the mixture with stirring. Filter out the precipitated solid compound III-20; HPLC purity is 96%, yield is 95%, and optical purity ee = 91.3%.

[0063] The reaction formula is as follows:

[0064] (5) In a 500 ml reaction vessel, first add 300 g of dichloromethane, then add 20 g of II-19. Maintain the reaction temperature at 35–40 °C, then add 1.87 g of catalyst I-1. Maintain the reaction temperature and add 9.0 g of 30% hydrogen peroxide dropwise over 0.5 h. Monitor the reaction progress by HPLC. Then stir with 36 ml of 10% sodium bisulfite aqueous solution. After phase separation, extract the aqueous phase with 200 ml of dichloromethane. Concentrate the combined organic phases (PE:EA = 4:1) and perform column chromatography. After distilling to remove ethyl acetate and petroleum ether, slowly cool the mixture with stirring. Filter out the precipitated solid compound III-19 with an HPLC purity of 97%, a yield of 95%, and an optical purity of ee = 92.8%.

[0065] The reaction formula is as follows:

[0066] (6) In a 500 ml reaction vessel, first add 300 g of dichloromethane, then add 20 g of II-15. Maintain the reaction temperature at 35–40 °C, then add 1.87 g of catalyst I-1. Maintain the reaction temperature and add 9.0 g of 30% hydrogen peroxide dropwise over 0.5 h. Monitor the reaction progress by HPLC. Then stir with 36 ml of 10% sodium bisulfite aqueous solution. After phase separation, extract the aqueous phase with 200 ml of dichloromethane. Concentrate the combined organic phases (PE:EA = 3:1) and perform column chromatography. After distilling to remove ethyl acetate and petroleum ether, slowly cool the mixture with stirring. Filter out the precipitated solid compound III-15 with an HPLC purity of 95%, a yield of 95%, two chiral neutral compounds, and optical purity of ee(R,R) = 84% and ee(S,R) = 92.0%.

[0067] Compound III-15 has two chiral centers at positions 1 and 2. The configurations of the two chiral centers of this compound are represented by (*,*). The first * represents the configuration at position 1, and the second * represents the configuration at position 2. For example, the configuration (S,R) represents a compound with the S configuration at position 1 and the R configuration at position 2.

[0068] The formula for calculating ee(R,R) is: [(R,R)-(R,S)] / [(R,R)+(R,S)]*100%, and the formula for calculating ee(S,R) is: [(S,R)-(S,S)] / [(S,R)+(S,S)]*100%.

[0069] The reaction formula is as follows:

[0070] (7) In a 500 ml reaction vessel, first add 300 g of dichloromethane, then add 20 g of II-17. Maintain the reaction temperature at 35–40 °C, then add 1.80 g of catalyst I-1. Maintain the reaction temperature and add 8.6 g of 30% hydrogen peroxide dropwise over 0.5 h. Monitor the reaction progress by HPLC. Then stir with 36 ml of 10% sodium bisulfite aqueous solution. After phase separation, extract the aqueous phase with 200 ml of dichloromethane. Concentrate the combined organic phases (PE:EA = 3:1) and perform column chromatography. After distilling to remove ethyl acetate and petroleum ether, slowly cool the mixture with stirring. Filter out the precipitated solid compound III-17. HPLC purity was 94%, yield 95%. Optical purity ee = 86.2%.

[0071] The reaction formula is as follows:

[0072] Example 4

[0073] (1) Preparation of catalyst I-2:

[0074] 10 g of isopropanol, 2 g of V-2, and 1.72 g of VI were added sequentially to the reaction flask, and the reaction was carried out at room temperature for 1 hour. After the reaction was complete, 1.81 g of isopropyl titanate was added dropwise to the system. One hour after the addition was completed, a solid precipitated during the reaction. This solid was filtered and dried at 40 °C for 5 hours to obtain 3.5 g of pure yellow powdered catalyst I-2, with a yield of 92% and a purity of 98%. ESI-MS analysis of the product showed m / z = 631.2 [M+H]. + .

[0075] Intermediate IV-2 NMR data:

[0076] 1HNMR (CDCl3, 300MHz): δ (ppm): 1.41 (t, J = 7.0Hz, 3H), 2.18 (t, J = 6.0Hz, 1H), 4.05-4.02 (d, J = 6.0Hz, 2H), 4.28-4.22 (q, J = 12.0Hz, 2H) ,4.68-4.66(q,J=12.0Hz,1H),5.9(s,1H),6.92-6.89(dd,J=6.0Hz,1H),7.05-7.02(dd,J=6.0Hz,1H),7.41-7.32(m,6H),8.36(1H,s).

[0077] NMR data for compound I-2:

[0078] 1 HNMR (CDCl3, 300MHz): δ (ppm): 1.29 (t, J = 7.0Hz, 6H), 3.93-3.91 (d, J = 6.0Hz, 4H), 4.66-4.62 (q, J = 12.0Hz, 2H), 5.02-4.98 (q, J = 12.0Hz, 2H), 5.54 -5.51(q,J=9.0Hz,2H),6.64-6.61(dd,J=9.0Hz,2H),6.81-6.79(dd,J=6.0Hz,2H),6.93-6.91(dd,J=6.0Hz,2H),7.48-7.39(m,10H),8.22(2H,s).

[0079] (2) Preparation of compound III-1:

[0080] Compound III-1 was obtained by reacting raw material II-1 with catalyst I-2 according to step (2) in Example 1. The product purity was 97.3%, the yield was 96%, and the ee value was 80%.

[0081] Comparative Example 1

[0082] (1) Preparation of catalyst A-1

[0083] 10 g of isopropanol, 0.93 g of B-1, and 0.95 g of C-1 were added sequentially to a reaction flask, and the reaction was carried out at room temperature for 1 hour. After the reaction was completed, 1.0 g of isopropyl titanate was added dropwise to the system. After the addition was completed, the reaction was carried out for 1 hour. During the reaction, a solid precipitated. The solid was filtered and dried at 40 °C for 5 hours to obtain pure yellow powdered catalyst A-1, weighing 1.5 g, with a yield of 90% and a purity of 97%.

[0084] The reaction equation is as follows:

[0085] (2) Preparation of compound III-1:

[0086] Compound III-1 was obtained by reacting with catalyst A-1 according to step (2) in Example 1. The purity, yield and ee value of the product were recorded. The molar equivalent of catalyst A-1 was the same as that of catalyst I in Example 2. The results are shown in Table 1.

[0087] Comparative Example 2

[0088] (1) Preparation of catalyst A-2:

[0089] 10 g of isopropanol, 1.37 g of B-2, and 0.7 g of C-2 were added sequentially to a reaction flask, and the reaction was carried out at room temperature for 1 hour. After the reaction was completed, 1.0 g of isopropyl titanate was added dropwise to the system. After the addition was completed, the reaction was carried out for 1 hour. During the reaction, a solid precipitated. The solid was filtered and dried at 40 °C for 5 hours to obtain pure yellow powdered catalyst A-2, weighing 2.3 g, with a yield of 87% and a purity of 98%.

[0090] The reaction equation is as follows:

[0091] (2) Preparation of compound III-1:

[0092] Compound III-1 was obtained by reacting with catalyst A-2 according to step (2) in Example 1. The purity, yield and ee value of the product were recorded. The molar equivalent of catalyst A-2 was the same as that of catalyst I in Example 2. The results are shown in Table 2.

[0093] Table 2 Catalytic effects of comparative catalysts

[0094] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A catalyst, as shown in Formula I: in, R1 is methyl or ethyl; C* is a chiral center, both of which are R configuration or both are S configuration, and based on the content of stereoisomers having R and S configurations at the said positions, they have a stereochemical purity of 50.5-100% (R) or (S), preferably 60-100% (R) or (S), more preferably 80-100% (R) or (S), further preferably 90-100% (R) or (S), and even more preferably 95-100% (R) or (S).

2. The method for preparing the catalyst according to claim 1, characterized in that, Catalyst I is composed of ligand compound IV. The reaction is prepared by complexation with a titanium reagent; preferably, the titanium reagent is selected from at least one of methyl titanate, ethyl titanate, isopropyl titanate, n-butyl titanate or titanium tetrachloride, and / or the reaction is carried out in the presence of a solvent; more preferably, the solvent is selected from at least one of dichloromethane, dichloroethane, methanol, ethanol, isopropanol, n-butanol, toluene, xylene or chloroform.

3. The method according to claim 2, characterized in that, Compound IV was prepared by reacting compound V and compound VI, as shown in the following reaction formula: Preferably, the reaction is carried out in the presence of a solvent; more preferably, the solvent is selected from at least one of dichloromethane, dichloroethane, methanol, ethanol, isopropanol, n-butanol, toluene, xylene, or chloroform.

4. The application of the catalyst as described in claim 1 in the asymmetric oxidation of sulfoxide compounds to prepare single enantiomers or enantiomer-enriched forms of sulfoxide compounds; Preferably, the thioether compound is The sulfoxide compounds in, X represents C1-C6 alkyl; Q represents C1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, or C1-C6 alkyl, C2-C6 alkenyl, or C2-C6 alkynyl substituted with at least one group selected from halogen, cyano, hydroxyl, amino, C1-C6 alkoxy, C1-C6 alkylthio, or C3-C6 cycloalkyl. Z1 represents C1-C6 alkoxy, halogen, C1-C6 alkylthio, C1-C6 alkylsulfoxide, C1-C6 alkylsulfonyl, or C1-C6 alkoxy-C1-C6 alkyl. Z2 represents a halo-C1-C6 alkyl group; or... X represents methyl; Q represents methyl, ethyl, propyl, butyl, trifluoromethyl, Methoxyethyl, methylthioethyl, or cyclopropylmethyl; Z1 represents fluorine, chlorine, methoxy, ethoxy, methylthio, ethylthio, butylthio, methyl sulfoxide, methyl sulfonyl, or methoxymethyl; Z2 represents CF3 or CHF2; More preferably, the enantiomer ratio is 50.5:49.5 to 100:0 (R):(S) or (S):(R), preferably 60:40 to 100:0 (R):(S) or (S):(R), more preferably 80:20 to 100:0 (R):(S) or (S):(R), further preferably 90:10 to 100:0 (R):(S) or (S):(R), and even more preferably 95:5 to 100:0 (R):(S) or (S):(R). More preferably, the thioether compound is selected from any one of compounds II-1 to II-23 in the specification.

5. A method for preparing a single enantiomer or an enantiomer-enriched form of a sulfoxide compound, comprising the following steps: Compound II is oxidized in the presence of catalyst I and an oxidant to give compound III, as shown in the following reaction equation: Wherein, the catalyst I as described in claim 1, S* is a chiral center; X represents C1-C6 alkyl; Q represents C1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, or C1-C6 alkyl, C2-C6 alkenyl, or C2-C6 alkynyl substituted with at least one group selected from halogen, cyano, hydroxyl, amino, C1-C6 alkoxy, C1-C6 alkylthio, or C3-C6 cycloalkyl. Z1 represents C1-C6 alkoxy, halogen, C1-C6 alkylthio, C1-C6 alkylsulfoxide, C1-C6 alkylsulfonyl, or C1-C6 alkoxy-C1-C6 alkyl. Z2 represents a halogenated C1-C6 alkyl group; Preferably, X represents methyl; Q represents methyl, ethyl, propyl, butyl, trifluoromethyl, Methoxyethyl, methylthioethyl, or cyclopropylmethyl; Z1 represents fluorine, chlorine, methoxy, ethoxy, methylthio, ethylthio, butylthio, methyl sulfoxide, methyl sulfonyl, or methoxymethyl; Z2 represents CF3 or CHF2; More preferably, the thioether compound is selected from any one of compounds II-1 to II-23 in the specification.

6. The method according to claim 5, characterized in that, The oxidant is selected from at least one of hydrogen peroxide, tert-butanol peroxide, or cumene hydroperoxide.

7. The method according to any one of claims 5-6, characterized in that, The reaction is carried out in the presence of a solvent; preferably, the solvent is selected from at least one of dichloromethane, dichloroethane, chloroform, alcohol, acetonitrile, DMF, DMSO, dioxane, or ethyl acetate.

8. The method according to any one of claims 5-7, characterized in that, The molar ratio of catalyst I to compound II is 0.01 to 0.2:1, and / or the molar ratio of oxidant to compound II is 1 to 2:1; preferably, the molar ratio of catalyst I to compound II is 0.05 to 0.1:

1.

9. The method according to any one of claims 5-8, characterized in that, The reaction temperature is 0–50°C.

10. The method according to any one of claims 5-9, characterized in that, The enantiomer ratio is 50.5:49.5 to 100:0 (R):(S) or (S):(R), preferably 60:40 to 100:0 (R):(S) or (S):(R), more preferably 80:20 to 100:0 (R):(S) or (S):(R), further preferably 90:10 to 100:0 (R):(S) or (S):(R), and even more preferably 95:5 to 100:0 (R):(S) or (S):(R).

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