A method for biomimetic catalytic aerobic oxidation of heteroatomic compounds

Abstract

The application discloses a method for biomimetic catalytic aerobic oxidation of heteroatomic compounds, and belongs to the technical field of organic synthesis. The method is characterized in that various tertiary phosphine compounds, sulfides, boric acids, trivalent arsine compounds and sulfophenols are reacted with oxygen under the condition of air or oxygen in the presence of a simple and easily obtained catalyst (antipyrine) and a cheap green reducing agent (ascorbic acid), so that corresponding oxidation products are efficiently obtained. The various oxidation products synthesized by the method are important organic synthesis elements and drug molecular building blocks. The biomimetic catalytic oxidation method can generate various tertiary phosphine oxides, sulfoxide compounds, oxidized arsine compounds, phenolic compounds and disulfide compounds in high yield under mild conditions by using the cheap green ascorbic acid as a reducing agent; the reaction has the advantages of green and cheap reagents, environmental friendliness, mild conditions, simple operation, easy amplification, wide substrate range and good functional group tolerance, and exhibits good economic practicability and industrial application prospect.

Description

Technical Field

[0001] This invention belongs to, but is not limited to, the field of organic synthesis technology, and specifically relates to a method for efficiently synthesizing various heteroatom oxidation products through biomimetic catalytic aerobic oxidation. Background Technology

[0002] Oxidation reactions play a vital role in nature and are a key transformation step in organic synthesis. With the deepening of green chemistry and sustainable development concepts, constructing efficient and environmentally friendly organic synthesis methods has become an important research direction in the field of chemistry. Traditional oxidation methods heavily rely on stoichiometric strong oxidants (such as hydrogen peroxide, potassium permanganate, m-chloroperoxybenzoic acid, periodate, etc.). While these methods are effective, they suffer from prominent problems such as poor atom economy, the generation of toxic byproducts, harsh reaction conditions, and difficulty in precisely controlling selectivity. Photocatalytic oxidation and transition metal catalytic oxidation, which have been developed in recent years, have achieved aerobic oxidation to some extent, but they also suffer from high costs and potential metal residues. Flavin monooxygenases are a class of flavin-dependent oxidoreductases widely found in organisms. They can utilize oxygen from the air to efficiently oxidize various tertiary phosphine compounds, thioethers, boric acids, arsines, and thiophenols under mild environmental conditions, avoiding the oxidation side reactions caused by strong oxidants in chemical oxidation processes. However, the high production cost, stringent storage and operating conditions, and limited substrate applicability of flavin monooxygenases greatly restrict their practical application. Therefore, developing a new oxidation method that is mild, uses safe reagents, is simple to operate, compatible with various substrates, is atom-economical, green, and efficient is of great significance for providing an efficient and convenient new strategy for the preparation of important tertiary phosphine oxides, sulfoxides, phenols, arsine oxides, and disulfide compounds. Summary of the Invention

[0003] To overcome the aforementioned technical deficiencies, this invention provides a novel biomimetic catalytic aerobic oxidation method that mimics the oxidation process catalyzed by flavin monooxygenase in vivo. This method is characterized by its mildness, convenience, high efficiency, and high selectivity, utilizing readily available and inexpensive air (or oxygen) to prepare various heteroatom oxidation products. It aims to address the problems of high catalyst costs, the need for stoichiometric strong oxidants, poor reaction selectivity, complex operation, and safety and environmental unfriendliness in existing oxidation processes.

[0004] The method of this invention can achieve oxidation reaction using oxygen as an oxidant without the need for special conditions such as photocatalysis and strong oxidants, thus truly simulating the flavin-dependent oxidase in vivo.

[0005] Specifically, the present invention provides a biomimetic catalytic aerobic oxidation method for heteroatom compounds, characterized in that: under air or oxygen conditions in the presence of a catalyst, a reducing agent, and a solvent, tertiary phosphine compounds, thioethers, boric acids, arsines, and thiophenols are oxidized to obtain the corresponding oxidation products; Here, the catalyst is a substituted allourea or a monohydrate or polyhydrate of a substituted allourea; The reducing agent is a hydrazine solution, zinc powder, symmetrically structured hansyl ester, ascorbic acid derivative, or crude extract containing ascorbic acid; optionally, the structure of the reducing agent is: ; The solvent is one or more of the following: acetonitrile, acetone, N,N-dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, 2-methyltetrahydrofuran, methanol, ethanol, trifluoroethanol, water, toluene, dichloromethane, chloroform, carbon tetrachloride, dichloroethane, tetrachloroethane, and ethyl acetate, preferably a 2-methyltetrahydrofuran / water or ethanol / water mixed solvent.

[0006] In the biomimetic catalytic aerobic oxidation method of the present invention, the tertiary phosphine compound having the structure shown in formula (I) yields the tertiary phosphine oxide shown in formula (II); the thioether compound having the structure shown in formula (III) yields the sulfoxide compound shown in formula (IV); the triphenylarsine compound having the structure shown in formula (V) yields the structure shown in formula (VI); the arylboronic acid compound having the structure shown in formula (VII) yields the phenolic compound shown in formula (VIII); and the thiophenol compound having the structure shown in formula (IX) yields the disulfide compound shown in formula (X). ; ; ; ; ; The molecular structure of the allourea catalyst is as follows: ; Where: R¹, R², R³, R 4 R 5 Substituents attached to S or P atoms In formulas (I), (II), (III), (IV) and the allourea catalyst, R¹, R², R³, R 4 R 5 R 6 R 7Each group is independently selected from the following groups: hydrogen, C1-C10 alkyl, substituted or unsubstituted aryl, C1-C10 alkoxy, C1-C10 alkyl-substituted thio, halogen, C1-C5 ester, carbonyl, amide, hydroxyl, nitro, carboxyl; wherein, R¹, R², R³, R… 4 R 5 R 6 R 7 They can be the same or different.

[0007] In the biomimetic catalytic aerobic oxidation method described in this invention, the reaction temperature is 0–70°C, preferably 25–30°C (room temperature).

[0008] In the biomimetic catalytic aerobic oxidation method described in this invention, the molar ratio of tertiary phosphine compound, thioether, boric acid, arsine compound, and thiophenol compound to albumin catalyst is 1:0.01 to 1, with the ratio of tertiary phosphine compound, thioether, boric acid, and arsine compound preferably being 1:0.1; and the ratio of thiophenol compound preferably being 1:0.05.

[0009] In the biomimetic catalytic aerobic oxidation method described in this invention, the molar ratio of tertiary phosphine compound, thioether, boric acid, arsine compound, and thiophenol compound to reducing agent is 1:0.5 to 50, with the ratio of tertiary phosphine compound, thioether, boric acid, and arsine compound preferably being 1:2; and the ratio of thiophenol compound preferably being 1:1.

[0010] In the biomimetic catalytic aerobic oxidation method described in this invention, the concentrations of tertiary phosphine compounds, thioethers, boric acid, arsine compounds, and thiophenol compounds are 0.01–1.0 M, with the concentrations of tertiary phosphine compounds, boric acid, and arsine compounds preferably at 0.1 M; the concentrations of thioether compounds preferably at 0.2 M; and the concentrations of thiophenol compounds preferably at 0.4 M.

[0011] In the biomimetic catalytic aerobic oxidation method described in this invention, the reaction time is 0.1 to 72 hours, the oxidation time for tertiary phosphine compounds, boric acid, and arsine compounds is preferably 6 to 10 hours, and the oxidation time for thioether compounds and thiophenol compounds is preferably 12 hours.

[0012] This invention achieves highly efficient oxidation reactions of various heteroatoms in an air (or oxygen) system under mild room temperature conditions and in the presence of readily available catalysts and reducing agents. It prepares a variety of important tertiary phosphine oxides, sulfoxides, phenols, arsine oxides, and disulfide compounds with high efficiency, high selectivity, low cost, and environmental friendliness, exhibiting good functional group compatibility. The method uses inexpensive and environmentally friendly oxygen from the air as the oxidant, and the reagents are also inexpensive and environmentally friendly, eliminating the need for expensive metal catalysts and strong oxidants. Furthermore, the reaction solvents are all environmentally friendly. The reaction has the advantages of mild conditions, simple operation, and easy scale-up, with low requirements for raw materials and equipment, making it suitable for large-scale industrial production and compatible with unpurified primary raw materials. Therefore, it has promising prospects for practical applications.

[0013] When 4-chloroanisole is used as a substrate and oxidation is carried out at room temperature (28°C), the aerobic oxidation method using allourea-inspired catalysis in this invention can specifically generate the single target product sulfoxide with a yield of 99%, exhibiting excellent chemoselectivity. Furthermore, the post-reaction processing is simple, requiring only a simple extraction operation to obtain the sulfoxide product. In contrast, other reported sulfoxide oxidation methods have lower yields than this method and may generate sulfone byproducts, increasing the difficulty of separation and purification.

[0014] The objectives and other advantages of this invention will be achieved through the structural features expressly pointed out in the claims and description. Other features and advantages will be set forth in detail in the following parts of the description, particularly in the description of the embodiments. Detailed Implementation

[0015] To further clarify the purpose, technical solution, and advantages of this patent, the embodiments of the present invention will be described in detail below. Unless otherwise specified, all raw materials and reagents required for the reaction are commercially available. Furthermore, the embodiments and features described herein can be arbitrarily combined without conflict. It should be noted that the scope of protection of the present invention is not limited to the following embodiments; any technical solution implemented based on the description of the present invention falls within the scope of protection of the present invention.

[0016] Example 1: Preparation of triphenylphosphine oxide (compound 1)

[0017] a) In a 10 mL test tube, add triphenylphosphine (0.0262 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of 2-methyltetrahydrofuran / water (1 / 1, 1 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution and stir vigorously for 6 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate, combine the organic phases, dry to anhydrous sodium sulfate, and concentrate under reduced pressure to give the oxidation product (yield 99%).

[0018] b) In a 10 mL test tube, add triphenylphosphine (0.0262 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of 2-methyltetrahydrofuran / water (1 / 1, 1 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution and stir vigorously in open air for 2 hours. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate, combine the organic phases, concentrate under reduced pressure to give the oxidation product (yield 41%).

[0019] c) In a 10 mL test tube, add triphenylphosphine (0.0262 g, 0.1 mmol, 1.0 eq), diethyl 2,6-dimethyl-1,4-dihydro-3,5-pyridinedicarboxylate (0.0506 g, 0.2 mmol, 2.0 eq), and a mixed solvent of 2-methyltetrahydrofuran / water (1 / 1, 1 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution and stir vigorously for 6 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate. Combine the organic phases, dry to anhydrous sodium sulfate, concentrate under reduced pressure, and purify by rapid column chromatography to obtain the oxidation product (yield 93%).

[0020] d) In a 10 mL test tube, add triphenylphosphine (0.0262 g, 0.1 mmol, 1.0 eq), hydrazine hydrate solution (0.0183 g, 0.2 mmol, 2.0 eq), and a mixed solvent of 2-methyltetrahydrofuran / water (1 / 1, 1 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution and stir vigorously for 6 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate, combine the organic phases, concentrate under reduced pressure to give the oxidation product (yield 4%).

[0021] e) In a 10 mL test tube, add triphenylphosphine (0.0262 g, 0.1 mmol, 1.0 eq), zinc powder (0.0130 g, 0.2 mmol, 2.0 eq), and a mixed solvent of 2-methyltetrahydrofuran / water (1 / 1, 1 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution and stir vigorously for 6 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate, combine the organic phases, concentrate under reduced pressure to give the oxidation product (yield 5%).

[0022] f) In a 10 mL test tube, add triphenylphosphine (0.0262 g, 0.1 mmol, 1.0 eq), sodium ascorbate (0.0396 g, 0.2 mmol, 2.0 eq), and a mixed solvent of 2-methyltetrahydrofuran / water (1 / 1, 1 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution and stir vigorously for 6 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate, combine the organic phases, concentrate under reduced pressure to give the oxidation product (yield 11%).

[0023] g) In a 10 mL test tube, add triphenylphosphine (0.0262 g, 0.1 mmol, 1.0 eq), calcium ascorbate (0.0853 g, 0.2 mmol, 2.0 eq), and a mixed solvent of 2-methyltetrahydrofuran / water (1 / 1, 1 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution and stir vigorously for 6 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate, combine the organic phases, concentrate under reduced pressure to give the oxidation product (yield 7%).

[0024] h) In a 10 mL test tube, add triphenylphosphine (0.0262 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (0.0352 g, 0.2 mmol, 2.0 eq), and solvent 2-methyltetrahydrofuran (1 mL); stir briefly to dissolve the substrate. At room temperature, add 1,3-dimethylalbumin (0.0019 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution and stir vigorously for 6 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate, combine the organic phases, concentrate under reduced pressure to give the oxidation product (yield 47%).

[0025] i) In a 10 mL test tube, add triphenylphosphine (0.0262 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (0.0352 g, 0.2 mmol, 2.0 eq), and dimethyl sulfoxide (1 mL); stir briefly to dissolve the substrate. At room temperature, add 1,3-dimethylalbumin (0.0019 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution and stir vigorously for 6 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate, combine the organic phases, concentrate under reduced pressure to give the oxidation product (yield 45%).

[0026] j) In a 10 mL test tube, add triphenylphosphine (0.0262 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of acetonitrile / water (1 / 1, 1 mL); stir briefly to dissolve the substrate. At room temperature, add 1,3-dimethylalbumin (0.0019 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution and stir vigorously for 6 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate, combine the organic phases, concentrate under reduced pressure to give the oxidation product (yield 64%).

[0027] k) In a 10 mL test tube, add triphenylphosphine (0.0262 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of 2-methyltetrahydrofuran / water (1 / 1, 1 mL); stir briefly to dissolve the substrate. At room temperature, add 1,3-dimethylalbumin (0.0019 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution and stir vigorously for 6 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate, combine the organic phases, concentrate under reduced pressure to give the oxidation product (yield 98%).

[0028] l) In a 10 mL test tube, add triphenylphosphine (0.0262 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of 2-methyltetrahydrofuran / water (1 / 1, 1 mL); stir briefly to dissolve the substrate. At room temperature, add 1-methylalbumin (0.0018 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution, and stir vigorously for 6 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate, combine the organic phases, concentrate under reduced pressure to give the oxidation product (yield 95%).

[0029] m) In a 10 mL test tube, add triphenylphosphine (1.31 g, 5 mmol, 1.0 eq), L-ascorbic acid (1.76 g, 0.2 mmol, 2.0 eq), and a mixed solvent of 2-methyltetrahydrofuran / water (1 / 1, 50 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.08 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution and stir vigorously for 6 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate, combine the organic phases, concentrate under reduced pressure to give the oxidation product (yield 99%).

[0030] n) In a 10 mL test tube, add triphenylphosphine (0.0262 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of 2-methyltetrahydrofuran / water (1 / 1, 1 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution, and stir vigorously for 6 hours under an oxygen atmosphere. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate, combine the organic phases, dry to anhydrous sodium sulfate, and concentrate under reduced pressure to give the oxidation product (yield 98%).

[0031] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 7.67 (ddt, J = 12.0, 6.9, 1.4 Hz, 6H), 7.57 - 7.51 (m, 3H), 7.46 (ddd, J = 8.8, 7.1, 3.0 Hz, 6H). Example 2: Preparation of tris(4-methylphenyl)phosphine oxide (Compound 2)

[0032] In a 10 mL test tube, add triphenylmethylphosphine (0.0304 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of 2-methyltetrahydrofuran / water (1 / 1, 1 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution and stir vigorously for 6 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate. Combine the organic phases, dry to anhydrous sodium sulfate, and concentrate under reduced pressure to give the oxidation product (yield 95%).

[0033] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 7.56 - 7.49 (m, 6H), 7.25 (dd, J =8.1, 2.6 Hz, 6H), 2.39 (s, 9H). Example 3: Preparation of tris(3-methoxyphenyl)-phosphine oxide (compound 3)

[0034] In a 10 mL test tube, tris(3-methoxyphenyl)phosphine (0.0352 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of 2-methyltetrahydrofuran / water (1 / 1, 1 mL) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) was added to the stirred reaction solution, and the mixture was vigorously stirred for 6 hours in open air. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (yield 97%).

[0035] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 7.35 (td, J = 7.9, 3.8 Hz, 3H), 7.30 - 7.25 (m, 3H), 7.16 - 7.10 (m, 3H), 7.08 - 7.00 (m, 3H), 3.79 (s, 9H). Example 4: Preparation of diphenyl(o-methoxyphenyl)phosphine oxide (compound 4)

[0036] In a 10 mL test tube, diphenyl(o-methoxyphenyl)phosphine (0.0292 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of 2-methyltetrahydrofuran / water (1 / 1, 1 mL) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) was added to the stirred reaction solution, and the mixture was vigorously stirred for 6 hours in open air. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (99% yield).

[0037] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 7.75 (ddd, J = 13.4, 7.6, 1.8 Hz,1H), 7.72 - 7.67 (m, 4H), 7.54 - 7.48 (m, 3H), 7.42 (td, J = 7.7, 2.9 Hz,4H), 7.07 (ddt, J = 8.6, 6.7, 1.4 Hz, 1H), 6.91 (ddt, J = 8.3, 5.3 Hz, 1H), 3.54 (s, 3H). Example 5: Preparation of tris(4-fluorophenyl)phosphine oxide (Compound 5)

[0038] a) In a 10 mL test tube, add tris(4-fluorophenyl)phosphine (0.0316 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of 2-methyltetrahydrofuran / water (1 / 1, 1 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution and stir vigorously for 6 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate, combine the organic phases, dry to anhydrous sodium sulfate, and concentrate under reduced pressure to give the oxidation product (yield 99%).

[0039] b) In a 10 mL test tube, add tris(4-fluorophenyl)phosphine (0.0316 g, 0.1 mmol, 1.0 eq), acerola cherry extract (containing 17% vitamin C, 0.3105 g), and a mixed solvent of 2-methyltetrahydrofuran / water (1 / 1, 1 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution and stir vigorously for 6 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate, combine the organic phases, dry to anhydrous sodium sulfate, and concentrate under reduced pressure to give the oxidation product (yield 99%).

[0040] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 7.64 (ddd, J = 11.7, 8.6, 5.6 Hz, 6H), 7.17 (td, J = 8.7, 2.1 Hz, 6H). Example 6: Preparation of tris(4-chlorophenyl)phosphine oxide (Compound 6)

[0041] In a 10 mL test tube, tris(4-chlorophenyl)phosphine (0.0365 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of 2-methyltetrahydrofuran / water (1 / 1, 1 mL) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) was added to the stirred reaction solution, and the mixture was vigorously stirred for 6 hours in open air. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (99% yield).

[0042] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 7.61 - 7.50 (m, 6H), 7.46 (dd, J =8.5, 2.4 Hz, 6H). Example 7: Preparation of tris(4-trifluorotolyl)phosphine oxide (Compound 7)

[0043] In a 10 mL test tube, tris(4-trifluorotoluyl)phosphine (0.0466 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of 2-methyltetrahydrofuran / water (1 / 1, 1 mL) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) was added to the stirred reaction solution, and the mixture was vigorously stirred for 6 hours in open air. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (99% yield).

[0044] Product characterization: 1 H NMR (400 MHz, CDCl3) δ 7.88 - 7.73 (m, 12H). Example 8: Preparation of [1,1'-biphenyl]-2-yldiphenylphosphine oxide (Compound 8)

[0045] In a 10 mL test tube, 2-diphenylphosphine-biphenyl (0.0338 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of 2-methyltetrahydrofuran / water (1 / 1, 1 mL) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) was added to the stirred reaction solution, and the mixture was vigorously stirred for 6 hours in open air. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (yield 97%).

[0046] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 7.61 - 7.52 (m, 5H), 7.44 - 7.36 (m, 3H), 7.35 - 7.28 (m, 6H), 7.22 - 7.17 (m, 2H), 7.09 - 7.01 (m, 3H). Example 9: Preparation of diphenyltolylphosphine oxide (Compound 9)

[0047] In a 10 mL test tube, diphenyltolylphosphine (0.0276 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of 2-methyltetrahydrofuran / water (1 / 1, 1 mL) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) was added to the stirred reaction solution, and the mixture was vigorously stirred for 6 hours in open air. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (yield 98%).

[0048] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 7.70 - 7.61 (m, 4H), 7.57 - 7.49(m, 4H), 7.43 (td, J = 7.7, 2.8 Hz, 4H), 7.25 (dd, J = 8.1, 2.7 Hz, 2H), 2.38(s, 3H). Example 10: Preparation of tri-m-phenylphosphine oxide (Compound 10)

[0049] In a 10 mL test tube, diphenyltolylphosphine (0.0304 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of 2-methyltetrahydrofuran / water (1 / 1, 1 mL) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) was added to the stirred reaction solution, and the mixture was vigorously stirred for 6 hours in open air. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (yield 98%).

[0050] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 7.54 (d, J = 12.5 Hz, 3H), 7.39 -7.31 (m, 9H), 2.36 (s, 9H). Example 11: Preparation of tris(3,5-dimethyl)phosphine oxide (compound 11)

[0051] In a 10 mL test tube, tris(3,5-xylyl)phosphine (0.0346 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of 2-methyltetrahydrofuran / water (1 / 1, 1 mL) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) was added to the stirred reaction solution, and the mixture was vigorously stirred for 6 hours in open air. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (yield 98%).

[0052] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 7.27 (d, J = 12.3 Hz, 6H), 7.13 (s,3H), 2.30 (s, 18H). Example 12: 4-Diphenylphosphinobenzoic acid (Compound 12)

[0053] In a 10 mL test tube, 4-diphenylphosphine benzoic acid (0.0306 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of 2-methyltetrahydrofuran / water (1 / 1, 1 mL) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) was added to the stirred reaction solution, and the mixture was vigorously stirred for 6 hours in open air. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (yield 97%).

[0054] Product characterization: 1 H NMR (400 MHz, DMSO-D6) δ 8.09 (dd, J = 8.2, 2.4 Hz, 2H), 7.80 - 7.73 (m, 2H), 7.67 - 7.53 (m, 10H). Example 13: Preparation of 2-(diphenyloxyphosphino)benzaldehyde (Compound 13)

[0055] In a 10 mL test tube, 0.0290 g (0.1 mmol, 1.0 eq) of 2-diphenylphosphine benzaldehyde, 0.0352 g (0.2 mmol, 2.0 eq) of L-ascorbic acid (also known as vitamin C), and 1 / 1 mL (2-methyltetrahydrofuran / water) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, 0.0016 g (0.01 mmol, 0.1 eq) of alluronide monohydrate was added to the stirred reaction solution, and the mixture was vigorously stirred for 6 hours in open air. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (yield 97%).

[0056] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 10.74 (s, 1H), 8.15 (ddd, J = 7.8,3.7, 1.3 Hz, 1H), 7.69 - 7.47 (m, 12H), 7.23 (ddd, J = 13.7, 7.6, 1.2 Hz,1H). Example 14: Preparation of diphenyl(pyridin-2-yl)phosphine oxide (compound 14)

[0057] In a 10 mL test tube, diphenyl-2-pyridinium phosphine (0.0263 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of 2-methyltetrahydrofuran / water (1 / 1, 1 mL) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) was added to the stirred reaction solution, and the mixture was vigorously stirred for 6 hours in open air. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (yield 98%).

[0058] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 8.77 (dt, J = 4.7, 1.3 Hz, 1H), 8.30 (ddt, J = 8.1, 5.8, 1.2 Hz, 1H), 7.92 - 7.81 (m, 5H), 7.53 - 7.49 (m,2H), 7.46 - 7.42 (m, 4H), 7.39 - 7.36 (m, 1H). Example 15: Preparation of tris(2-furanyl)phosphine oxide (compound 15)

[0059] In a 10 mL test tube, tris(2-furanyl)phosphine (0.0232 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of 2-methyltetrahydrofuran / water (1 / 1, 1 mL) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) was added to the stirred reaction solution, and the mixture was vigorously stirred for 6 hours in open air. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (yield 99%).

[0060] Product characterization: 1 H NMR (400 MHz, CDCl3) δ 7.76 - 7.70 (m, 3H), 7.16 (ddd, J =3.4, 2.1, 0.7 Hz, 3H), 6.55 (dt, J = 3.4, 1.7 Hz, 3H). Example 16: Preparation of methyldiphenylphosphine oxide (compound 16)

[0061] In a 10 mL test tube, diphenylmethoxyphosphine (0.02 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of 2-methyltetrahydrofuran / water (1 / 1, 1 mL) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) was added to the stirred reaction solution, and the mixture was vigorously stirred for 6 hours in open air. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (99% yield).

[0062] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 7.76 - 7.68 (m, 4H), 7.55 - 7.49(m, 2H), 7.46 (td, J = 8.0, 2.8 Hz, 4H), 2.01 (d, J = 13.2 Hz, 3H). Example 17: Preparation of tert-butyldiphenylphosphine oxide (Compound 17)

[0063] In a 10 mL test tube, tert-butyldiphenylphosphine (0.0242 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of 2-methyltetrahydrofuran / water (1 / 1, 1 mL) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) was added to the stirred reaction solution, and the mixture was vigorously stirred for 6 hours in open air. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (yield 96%).

[0064] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 7.93 (ddd, J = 10.0, 7.6, 1.4 Hz, 4H), 7.52 - 7.44 (m, 6H), 1.23 (d, J = 15.0 Hz, 9H). Example 18: Preparation of benzyl diphenylphosphine oxide (compound 18)

[0065] In a 10 mL test tube, benzyldiphenylphosphine (0.0242 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of 2-methyltetrahydrofuran / water (1 / 1, 1 mL) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) was added to the stirred reaction solution, and the mixture was vigorously stirred for 6 hours in open air. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (yield 97%).

[0066] Product characterization: 1H NMR (600 MHz, CDCl3) δ 7.69 (ddt, J = 11.4, 6.9, 1.4 Hz, 4H), 7.54 - 7.45 (m, 2H), 7.42 (td, J = 7.6, 2.9 Hz, 4H), 7.17 (d, J = 7.2Hz, 3H), 7.13 - 7.08 (m, 2H), 3.64 (d, J = 13.7 Hz, 2H). Example 19: Preparation of dimethylphenylphosphine oxide (Compound 19)

[0067] In a 10 mL test tube, dimethylphenylphosphine (0.0138 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of 2-methyltetrahydrofuran / water (1 / 1, 1 mL) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) was added to the stirred reaction solution, and the mixture was vigorously stirred for 6 hours in open air. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (yield 99%).

[0068] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 7.71 - 7.64 (m, 2H), 7.49 - 7.40 (m, 3H), 1.67 (d, J = 13.0 Hz, 6H). Example 20: Preparation of di-tert-butyl(2'-(dimethylamino)-[1,1'-biphenyl]-2-yl)phosphine oxide (Compound 20)

[0069] In a 10 mL test tube, 2-di-tert-butylphospho-2-(N,N-dimethylamino)biphenyl (0.0341 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of 2-methyltetrahydrofuran / water (1 / 1, 1 mL) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) was added to the stirred reaction solution, and the mixture was vigorously stirred for 6 hours in open air. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (yield 97%).

[0070] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 7.63 - 7.55 (m, 1H), 7.49 (t, J =7.5 Hz, 1H), 7.38 - 7.29 (m, 2H), 7.26 (q, J = 4.4 Hz, 1H), 7.05 (d, J = 8.1Hz, 1H), 6.95 (d, J = 4.4 Hz, 2H), 2.46 (s, 6H), 1.37 (d, J = 13.3 Hz, 9H), 1.08 (d, J = 13.2 Hz, 9H). 13 C NMR (151 MHz, CDCl3) δ 153.27, 148.23, 148.20,137.29, 137.27, 133.41, 133.35, 130.10, 128.13, 124.70, 124.63, 121.15,118.00, 77.37, 76.95, 43.88, 37.22, 37.19, 36.83, 36.80, 28.47, 26.75. 31 P NMR (243 MHz, CDCl3) δ 51.72. HRMS (ESI): C 22 H 32 NOP, Neutral mass: 357.2222,Observed ([M+H]) + : 358.2291. Example 21: Preparation of diphenyl methyl phosphate (Compound 21)

[0071] In a 10 mL test tube, diphenylmethoxyphosphine (0.0216 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and the solvent 2-methyltetrahydrofuran (1 mL) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) was added to the stirred reaction solution, and the mixture was vigorously stirred for 6 hours in open air. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (99% yield).

[0072] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 7.84 - 7.78 (m, 4H), 7.52 (dt, J =7.5, 4.4 Hz, 2H), 7.45 (td, J = 7.6, 3.5 Hz, 4H), 3.76 (d, J = 11.1 Hz, 3H). Example 22: Preparation of phenyl diphenylphosphonate (Compound 22)

[0073] In a 10 mL test tube, phenol diphenylphosphite (0.0278 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and the solvent 2-methyltetrahydrofuran (1 mL) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) was added to the stirred reaction solution, and the mixture was vigorously stirred for 6 hours in open air. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (yield 88%).

[0074] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 7.89 (ddd, J = 12.6, 8.3, 1.4 Hz,4H), 7.55 - 7.51 (m, 2H), 7.46 (td, J = 7.6, 3.5 Hz, 4H), 7.25 - 7.19 (m,4H), 7.07 (t, J = 7.3 Hz, 1H). Example 23: Preparation of diphenylvinylphosphine oxide (Compound 23)

[0075] In a 10 mL test tube, vinyldiphenylphosphine (0.0212 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of 2-methyltetrahydrofuran / water (1 / 1, 1 mL) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) was added to the stirred reaction solution, and the mixture was vigorously stirred for 6 hours in open air. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (yield 98%).

[0076] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 7.68 (dd, J = 12.1, 7.5 Hz, 4H), 7.53 - 7.39 (m, 6H), 6.65 (ddd, J = 24.6, 18.5, 12.6 Hz, 1H), 6.37 - 6.16 (m, 2H). Example 24: Preparation of methylenebis(diphenylphosphine oxide) (Compound 24)

[0077] In a 10 mL test tube, add bis(diphenylphosphine)methane (0.0384 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0704 g, 0.4 mmol, 4.0 eq), and a mixed solvent of 2-methyltetrahydrofuran / water (1 / 1, 1 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.0032 g, 0.02 mmol, 0.2 eq) to the stirred reaction solution, and stir vigorously for 6 hours under an oxygen atmosphere. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate. Combine the organic phases, dry to anhydrous sodium sulfate, and concentrate under reduced pressure to give the oxidation product (yield 98%).

[0078] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 7.72 (dd, J = 11.7, 7.4 Hz, 8H), 7.37 (dt, J = 51.5, 7.7 Hz, 12H), 3.53 (t, J = 14.7 Hz, 2H). Example 25: Preparation of 1,2-ethylidene bis(diphenylphosphine oxide) (Compound 25)

[0079] In a 10 mL test tube, 1,2-bis(diphenylphosphine)ethane (0.0398 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0704 g, 0.4 mmol, 4.0 eq), and a mixed solvent of 2-methyltetrahydrofuran / water (1 / 1, 1 mL) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, allourea monohydrate (0.0032 g, 0.02 mmol, 0.2 eq) was added to the stirred reaction solution, and the mixture was vigorously stirred for 6 hours under an oxygen atmosphere. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (yield 98%).

[0080] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 7.70 (q, J = 6.4 Hz, 8H), 7.47 (dt, J = 38.1, 7.5 Hz, 12H), 2.51 (s, 4H). Example 26: Preparation of 1,3-propylidene bis(diphenylphosphine oxide) (Compound 26)

[0081] In a 10 mL test tube, 1,3-bis(diphenylphosphine)propane (0.0412 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0704 g, 0.4 mmol, 4.0 eq), and a mixed solvent of 2-methyltetrahydrofuran / water (1 / 1, 1 mL) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, allourea monohydrate (0.0032 g, 0.02 mmol, 0.2 eq) was added to the stirred reaction solution, and the mixture was vigorously stirred for 6 hours under an oxygen atmosphere. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (yield 97%).

[0082] Product characterization: 1H NMR (600 MHz, CDCl3) δ 7.67 (dd, J = 11.5, 7.6 Hz, 8H), 7.49 - 7.44 (m, 4H), 7.40 (td, J = 7.7, 2.7 Hz, 8H), 2.49 (dt, J = 11.0, 7.6Hz, 4H), 1.99 (ddt, J = 20.3, 13.3, 7.7 Hz, 2H). Example 27: Preparation of methyl 3-bromo-indole-5-carboxylate (Compound 27)

[0083] In a 10 mL test tube, add bis(2-diphenylphosphine) ether (0.0538 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0704 g, 0.4 mmol, 4.0 eq), and a mixed solvent of 2-methyltetrahydrofuran / water (1 / 1, 1 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.0032 g, 0.02 mmol, 0.2 eq) to the stirred reaction solution, and stir vigorously for 6 hours under an oxygen atmosphere. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate. Combine the organic phases, dry to anhydrous sodium sulfate, and concentrate under reduced pressure to give the oxidation product (yield 96%).

[0084] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 7.81 - 7.50 (m, 10H), 7.50 - 7.05 (m, 16H), 6.04 (dd, J = 8.2, 4.9 Hz, 2H). Example 28: Preparation of methyl phenyl sulfoxide (compound 28)

[0085] In a 10 mL test tube, add methyl phenyl sulfide (0.0124 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of anhydrous ethanol / water (1 / 1, 0.5 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution, and stir vigorously for 12 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate. Combine the organic phases, dry to anhydrous sodium sulfate, and concentrate under reduced pressure to give the oxidation product (yield 99%).

[0086] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 7.67 - 7.64 (m, 2H), 7.56 - 7.49 (m, 3H), 2.73 (s, 3H). Example 29: Preparation of methyl-p-toluene sulfoxide (compound 29)

[0087] In a 10 mL test tube, add 0.0138 g (0.1 mmol, 1.0 eq) of 1-methyl-4-methylthiobenzene, 0.0352 g (0.2 mmol, 2.0 eq) of L-ascorbic acid (also known as vitamin C), and anhydrous ethanol / water (1 / 1, 0.5 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution and stir vigorously for 12 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate. Combine the organic phases, dry to anhydrous sodium sulfate, and concentrate under reduced pressure to give the oxidation product (yield 99%).

[0088] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 7.56 - 7.51 (m, 2H), 7.35 - 7.31(m, 2H), 2.71 (s, 3H), 2.42 (s, 3H). Example 30: Preparation of 1-methoxy-4-(methylsulfinyl)benzene (Compound 30)

[0089] a) In a 10 mL test tube, add 4-methoxyanisole (0.0154 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of anhydrous ethanol / water (1 / 1, 0.5 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution and stir vigorously for 12 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate, combine the organic phases, dry to anhydrous sodium sulfate, and concentrate under reduced pressure to give the oxidation product (yield 99%).

[0090] b) In a 10 mL test tube, add 4-methoxyanisole (0.0154 g, 0.1 mmol, 1.0 eq), acerola cherry extract (containing 17% vitamin C, 0.3105 g), and a mixed solvent of anhydrous ethanol / water (1 / 1, 0.5 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution and stir vigorously for 12 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate. Combine the organic phases, dry to anhydrous sodium sulfate, and concentrate under reduced pressure to give the oxidation product (yield 97%).

[0091] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 7.60 (d, J = 8.8 Hz, 2H), 7.03 (d,J = 8.6 Hz, 2H), 3.86 (s, 3H), 2.70 (s, 3H). Example 31: Preparation of 2-(methanesulfinyl)anisole (Compound 31)

[0092] In a 10 mL test tube, add 2-methoxyanisole (0.0154 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of anhydrous ethanol / water (1 / 1, 0.5 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution, and stir vigorously for 12 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate. Combine the organic phases, dry to anhydrous sodium sulfate, and concentrate under reduced pressure to give the oxidation product (yield 99%).

[0093] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 7.82 (dd, J = 7.7, 1.7 Hz, 1H), 7.47 - 7.43 (m, 1H), 7.19 (td, J = 7.5, 0.9 Hz, 1H), 6.92 (dd, J = 8.3, 1.0Hz, 1H), 3.89 (s, 3H), 2.78 (s, 3H). Example 32: Preparation of 1-(methanesulfinyl)-4-nitrobenzene (Compound 32)

[0094] In a 10 mL test tube, add 4-nitroanisole (0.0169 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of anhydrous ethanol / water (1 / 1, 0.5 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution, and stir vigorously for 12 hours under an oxygen atmosphere. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate. Combine the organic phases, dry to anhydrous sodium sulfate, and concentrate under reduced pressure to give the oxidation product (yield 98%).

[0095] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 8.39 (d, J = 8.7 Hz, 2H), 7.84 (d,J = 8.7 Hz, 2H), 2.80 (s, 3H). Example 33: Preparation of p-chlorophenylmethyl sulfoxide (Compound 33)

[0096] a) In a 10 mL test tube, add 4-chloroanisole (0.0158 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of anhydrous ethanol / water (1 / 1, 0.5 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution and stir vigorously for 12 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate, combine the organic phases, dry to anhydrous sodium sulfate, and concentrate under reduced pressure to give the oxidation product (yield 99%).

[0097] b) In a 10 mL test tube, add 4-chloroanisole (0.0158 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and water (0.5 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution and stir vigorously for 12 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate, combine the organic phases, dry to anhydrous sodium sulfate, and concentrate under reduced pressure to give the oxidation product (yield 47%).

[0098] c) In a 10 mL test tube, add 4-chloroanisole (0.0158 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and anhydrous ethanol (0.5 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution and stir vigorously for 12 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate, combine the organic phases, dry to anhydrous sodium sulfate, and concentrate under reduced pressure to give the oxidation product (yield 13%).

[0099] d) In a 10 mL test tube, add 4-chloroanisole (0.0158 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent 2Me-THF / H2O (1 / 1, 0.5 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution and stir vigorously for 12 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate. Combine the organic phases, dry to anhydrous sodium sulfate, and concentrate under reduced pressure to give the oxidation product (yield 34%).

[0100] e) In a 10 mL test tube, add 4-chloroanisole (0.0158 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of anhydrous ethanol / water (1 / 1, 0.5 mL); stir briefly to dissolve the substrate. At room temperature, add 1,3-dimethylalbumin (0.0019 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution and stir vigorously in open air for 12 hours. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate, combine the organic phases, dry to anhydrous sodium sulfate, and concentrate under reduced pressure to give the oxidation product (yield 98%).

[0101] f) In a 10 mL test tube, add 4-chloroanisole (0.0158 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of anhydrous ethanol / water (1 / 1, 0.5 mL); stir briefly to dissolve the substrate. At room temperature, add 1-methylalbumin (0.0016 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution and stir vigorously for 12 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate, combine the organic phases, dry to anhydrous sodium sulfate, and concentrate under reduced pressure to give the oxidation product (yield 97%).

[0102] g) In a 10 mL test tube, add 4-chloroanisole (0.0158 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of anhydrous ethanol / water (1 / 1, 1 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution and stir vigorously for 12 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate, combine the organic phases, dry to anhydrous sodium sulfate, and concentrate under reduced pressure to give the oxidation product (yield 27%).

[0103] h) In a 10 mL test tube, add 4-chloroanisole (0.0158 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of anhydrous ethanol / water (1 / 1, 0.25 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution and stir vigorously for 12 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate, combine the organic phases, dry to anhydrous sodium sulfate, and concentrate under reduced pressure to give the oxidation product (yield 53%).

[0104] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 7.61 - 7.57 (m, 2H), 7.53 - 7.48 (m, 2H), 2.72 (s, 3H). Example 34: Preparation of p-bromophenylmethyl sulfoxide (Compound 34)

[0105] In a 10 mL test tube, add 4-bromoanisole (0.0203 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of anhydrous ethanol / water (1 / 1, 0.5 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution, and stir vigorously for 12 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate. Combine the organic phases, dry to anhydrous sodium sulfate, and concentrate under reduced pressure to give the oxidation product (yield 98%).

[0106] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 7.69 - 7.65 (m, 2H), 7.56 - 7.50 (m, 2H), 2.73 (s, 3H). Example 35: Preparation of m-bromophenylmethyl sulfoxide (Compound 35)

[0107] In a 10 mL test tube, add 0.0203 g (0.1 mmol, 1.0 eq) of 3-bromothioanisole, 0.2 mmol (also known as vitamin C) of L-ascorbic acid (0.0352 g, 2.0 eq) and a mixed solvent of anhydrous ethanol / water (1 / 1, 0.5 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution and stir vigorously for 12 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate. Combine the organic phases, dry to anhydrous sodium sulfate, and concentrate under reduced pressure to give the oxidation product (99% yield).

[0108] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 7.80 (t, J = 1.8 Hz, 1H), 7.62(ddd, J = 7.9, 1.9, 1.0 Hz, 1H), 7.54 (ddd, J = 7.8, 1.6, 1.0 Hz, 1H), 7.40(t, J = 7.9 Hz, 1H), 2.74 (s, 3H). Example 36: Preparation of 2-bromophenylmethyl sulfoxide (Compound 36)

[0109] In a 10 mL test tube, add 2-bromoanisole (0.0203 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of anhydrous ethanol / water (1 / 1, 0.5 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution, and stir vigorously for 12 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate. Combine the organic phases, dry to anhydrous sodium sulfate, and concentrate under reduced pressure to give the oxidation product (yield 99%).

[0110] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 7.95 (dd, J = 7.8, 1.7 Hz, 1H), 7.58 (ddd, J = 15.6, 7.7, 1.1 Hz, 2H), 7.38 (td, J = 7.6, 1.7 Hz, 1H), 2.83 (s, 3H). Example 37: Preparation of ethyl phenyl sulfoxide (compound 37)

[0111] In a 10 mL test tube, phenethyl sulfide (0.0138 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of anhydrous ethanol / water (1 / 1, 0.5 mL) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) was added to the stirred reaction solution, and the mixture was vigorously stirred for 12 hours in open air. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (yield 96%).

[0112] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 7.63 - 7.58 (m, 2H), 7.55 - 7.46(m, 3H), 2.96 - 2.86 (m, 1H), 2.81 - 2.74 (m, 1H), 1.19 (t, J = 7.4 Hz, 3H). Example 38: Preparation of (cyclosulfinyl)benzene (Compound 38)

[0113] In a 10 mL test tube, cyclopropyl phenyl sulfide (0.0150 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of anhydrous ethanol / water (1 / 1, 0.5 mL) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) was added to the stirred reaction solution, and the mixture was vigorously stirred for 12 hours in open air. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (yield 98%).

[0114] Product characterization: 1H NMR (600 MHz, CDCl3) δ 7.69 - 7.64 (m, 2H), 7.54 - 7.48(m, 3H), 2.29 - 2.24 (m, 1H), 1.26 - 1.22 (m, 1H), 1.05 - 1.01 (m, 1H), 0.99- 0.92 (m, 2H). Example 39: Preparation of 2-(methanesulfinyl)naphthalene (Compound 39)

[0115] In a 10 mL test tube, 2-(methylthio)naphthalene (0.0174 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of anhydrous ethanol / water (1 / 1, 0.5 mL) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) was added to the stirred reaction solution, and the mixture was vigorously stirred for 12 hours in open air. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (yield 85%).

[0116] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 8.22 (s, 1H), 7.99 (d, J = 8.6 Hz,1H), 7.96 - 7.90 (m, 2H), 7.60 (ddd, J = 7.9, 6.4, 1.8 Hz, 3H), 2.80 (s, 3H). Example 40: Preparation of diphenyl sulfoxide (Compound 40)

[0117] In a 10 mL test tube, diphenyl sulfide (0.0186 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of anhydrous ethanol / water (1 / 1, 0.5 mL) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) was added to the stirred reaction solution, and the mixture was vigorously stirred for 12 hours in open air. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (yield 41%).

[0118] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 7.67 - 7.63 (m, 4H), 7.48 - 7.43 (m, 6H). Example 41: Preparation of 2-(methanesulfinyl)thiophene (Compound 41)

[0119] In a 10 mL test tube, 2-(methylthiothiophene) (0.0130 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of anhydrous ethanol / water (1 / 1, 0.5 mL) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) was added to the stirred reaction solution, and the mixture was vigorously stirred for 12 hours in open air. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (yield 99%).

[0120] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 7.65 (dd, J = 5.0, 1.3 Hz, 1H), 7.49 (dd, J = 3.7, 1.3 Hz, 1H), 7.12 (dd, J = 5.0, 3.7 Hz, 1H), 2.93 (s, 3H). Example 42: Preparation of ((methylenesulfinyl)methyl)benzene (Compound 42)

[0121] In a 10 mL test tube, add benzyl methyl sulfide (0.0138 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of anhydrous ethanol / water (1 / 1, 0.5 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution, and stir vigorously for 12 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate. Combine the organic phases, dry to anhydrous sodium sulfate, and concentrate under reduced pressure to give the oxidation product (yield 97%).

[0122] Product characterization:1 H NMR (600 MHz, CDCl3) δ 7.40 - 7.34 (m, 3H), 7.31 - 7.27(m, 2H), 4.08 (d, J = 12.9 Hz, 1H), 3.93 (d, J = 12.8 Hz, 1H), 2.46 (s, 3H). Example 43: Preparation of thiochroman-4-one 1-oxide (Compound 43)

[0123] In a 10 mL test tube, add benzothiocyclopentyl-4-one (0.0164 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of anhydrous ethanol / hydrochloric acid aqueous solution (pH=4) (1 / 1, 0.5 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution, and stir vigorously for 12 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate. Combine the organic phases, dry to anhydrous sodium sulfate, and concentrate under reduced pressure to give the oxidation product (yield 86%).

[0124] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 8.19 (dd, J = 7.9, 1.4 Hz, 1H), 7.90 (dd, J = 7.7, 1.2 Hz, 1H), 7.78 (td, J = 7.6, 1.4 Hz, 1H), 7.68 (td, J =7.6, 1.3 Hz, 1H), 3.53 - 3.47 (m, 3H), 2.95 - 2.88 (m, 1H). Example 44: Preparation of (sulfinylbis(methylene))diphenyl (Compound 44)

[0125] In a 10 mL test tube, dibenzyl sulfide (0.0214 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of anhydrous ethanol / water (1 / 1, 0.5 mL) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) was added to the stirred reaction solution, and the mixture was vigorously stirred for 12 hours in open air. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (yield 98%).

[0126] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 7.41 - 7.32 (m, 6H), 7.30 - 7.28 (m, 4H), 3.97 - 3.85 (m, 4H). Example 45: Preparation of 2-(tert-butylsulfinyl)-2-methylpropane (Compound 45)

[0127] In a 10 mL test tube, tert-butyl sulfide (0.0146 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of anhydrous ethanol / water (1 / 1, 0.5 mL) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) was added to the stirred reaction solution, and the mixture was vigorously stirred for 12 hours in open air. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (yield 98%).

[0128] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 1.32 (s, 18H). Example 46: Preparation of 1-(Butylsulfinyl)butane (Compound 46)

[0129] In a 10 mL test tube, add n-butyl sulfide (0.0146 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of anhydrous ethanol / water (1 / 1, 0.5 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution, and stir vigorously for 12 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate. Combine the organic phases, dry to anhydrous sodium sulfate, and concentrate under reduced pressure to give the oxidation product (yield 98%).

[0130] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 2.71 - 2.60 (m, 4H), 1.78 - 1.69 (m, 4H), 1.55 - 1.40 (m, 4H), 0.95 (t, J = 7.4 Hz, 6H). Example 47: Preparation of 2-phenyl-1,3-dithiane 1-oxide (Compound 47)

[0131] In a 10 mL test tube, 2-phenyl-1,3-dithiane (0.0196 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of anhydrous ethanol / water (1 / 1, 0.5 mL) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) was added to the stirred reaction solution, and the mixture was vigorously stirred for 12 hours in open air. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (95% yield).

[0132] Product characterization: 1H NMR (600 MHz, CDCl3) δ 7.45 - 7.36 (m, 5H), 4.56 (s, 1H), 3.57 (dt, J = 11.5, 3.7 Hz, 1H), 2.89 (ddd, J = 14.6, 12.4, 2.6 Hz, 1H), 2.81- 2.67 (m, 2H), 2.54 (ddq, J = 14.2, 5.7, 2.9 Hz, 1H), 2.38 (dtt, J = 15.6,12.8, 3.1 Hz, 1H). Example 48: Preparation of isopropylpropane-2-sulfinyl thioester (Compound 48)

[0133] In a 10 mL test tube, add isopropyl disulfide (0.0150 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of anhydrous ethanol / water (1 / 1, 0.5 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution, and stir vigorously for 12 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate. Combine the organic phases, dry to anhydrous sodium sulfate, and concentrate under reduced pressure to give the oxidation product (yield 54%).

[0134] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 3.63 (hept, J = 6.8 Hz, 1H), 3.21 (hept, J = 6.9 Hz, 1H), 1.51 - 1.46 (m, 6H), 1.42 - 1.36 (m, 6H). Example 49: Preparation of 4-(methylenesulfinyl)phenol (Compound 49)

[0135] In a 10 mL test tube, add 4-(methylthio)phenol (0.0140 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of anhydrous ethanol / water (1 / 1, 0.5 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution, and stir vigorously for 12 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate. Combine the organic phases, dry to anhydrous sodium sulfate, and concentrate under reduced pressure to give the oxidation product (yield 91%).

[0136] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 7.49 (d, J = 8.4 Hz, 2H), 6.96 (d,J = 8.3 Hz, 2H), 2.75 (s, 3H). Example 50: Preparation of 4-(methanesulfinyl)benzaldehyde (Compound 50)

[0137] In a 10 mL test tube, 4-(methylmercapto)benzaldehyde (0.0152 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of anhydrous ethanol / water (1 / 1, 0.5 mL) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) was added to the stirred reaction solution, and the mixture was vigorously stirred for 12 hours in open air. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (yield 81%).

[0138] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 10.08 (s, 1H), 8.04 (d, J = 8.4 Hz, 2H), 7.82 (d, J = 8.3 Hz, 2H), 2.79 (s, 3H). Example 51: Preparation of 2-((4-chlorophenyl)sulfinyl)acetic acid (Compound 51)

[0139] In a 10 mL test tube, add (4-chlorophenylthiophenol)acetic acid (0.0202 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of anhydrous ethanol / water (1 / 1, 0.5 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution, and stir vigorously for 12 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate. Combine the organic phases, dry to anhydrous sodium sulfate, and concentrate under reduced pressure to give the oxidation product (yield 95%).

[0140] Product characterization: 1 H NMR (600 MHz, DMSO-D6) δ 7.74 (d, J = 8.2 Hz, 2H), 7.66 (d, J = 8.2 Hz, 2H), 4.05 (d, J = 14.4 Hz, 1H), 3.81 (d, J = 14.5 Hz, 1H). 13 CNMR (151 MHz, DMSO-D6) δ 167.15, 143.13, 136.41, 129.78, 126.79, 61.42. HRMS(ESI): C8H7ClO3S, Neutral mass: 217.9804, Observed ([M+H]) + : 218.9868. Example 52: Preparation of 2-(benzenesulfinyl)ethane-1-ol (Compound 52)

[0141] In a 10 mL test tube, add 0.0154 g (0.1 mmol, 1.0 eq) of 2-phenylthioethanol, 0.2 mmol (also known as vitamin C) of L-ascorbic acid (0.0352 g, 2.0 eq) and a mixed solvent of anhydrous ethanol / water (1 / 1, 0.5 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution and stir vigorously for 12 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate. Combine the organic phases, dry to anhydrous sodium sulfate, and concentrate under reduced pressure to give the oxidation product (yield 98%).

[0142] Product characterization: 1H NMR (600 MHz, CDCl3) δ 7.66 - 7.62 (m, 2H), 7.56 - 7.50(m, 3H), 4.16 (ddd, J = 12.1, 8.8, 3.1 Hz, 1H), 4.00 (ddd, J = 12.2, 5.5, 3.9Hz, 1H), 3.17 (ddd, J = 13.6, 8.8, 3.9 Hz, 1H), 2.88 (ddd, J = 13.6, 5.5, 3.1Hz, 1H). Example 53: Preparation of (allylsulfinyl)benzene (Compound 53)

[0143] In a 10 mL test tube, allyloxythiophenol (0.0150 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of anhydrous ethanol / water (1 / 1, 0.5 mL) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) was added to the stirred reaction solution, and the mixture was vigorously stirred for 12 hours in open air. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (yield 98%).

[0144] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 7.62 - 7.58 (m, 2H), 7.53 - 7.49(m, 3H), 5.65 (ddt, J = 17.5, 10.2, 7.5 Hz, 1H), 5.33 (dd, J = 10.2, 1.3 Hz, 1H), 5.20 (dq, J = 17.1, 1.3 Hz, 1H), 3.60 - 3.56 (m, 1H), 3.51 (ddt, J =12.8, 7.5, 0.9 Hz, 1H). Example 54: Preparation of methyl 2-(benzenesulfinyl)acetate (Compound 54)

[0145] In a 10 mL test tube, methyl phenyl thioacetate (0.0182 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of anhydrous ethanol / water (1 / 1, 0.5 mL) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) was added to the stirred reaction solution, and the mixture was vigorously stirred for 12 hours in open air. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (99% yield).

[0146] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 7.69 (dd, J = 6.7, 2.9 Hz, 2H), 7.55 (dd, J = 5.0, 1.9 Hz, 3H), 3.85 (d, J = 13.7 Hz, 1H), 3.71 (s, 3H), 3.67(d, J = 13.7 Hz, 1H). Example 55: Preparation of ((1R,4R)-1,7,7-trimethylbicyclo[2.2.1]hept-2-ylidene)-14-thioalkylone (Compound 55)

[0147] In a 10 mL test tube, (1R)-(-)-thiocamphor (0.0168 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of anhydrous ethanol / water (1 / 1, 0.5 mL) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, alliin monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) was added to the stirred reaction solution, and the mixture was vigorously stirred for 12 hours in open air. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (yield 80%).

[0148] Product characterization: 1H NMR (600 MHz, CDCl3) δ 3.05 - 2.96 (m, 1H), 2.54 (d, J =20.6 Hz, 1H), 2.05 (t, J = 4.2 Hz, 1H), 1.92 - 1.84 (m, 2H), 1.50 - 1.41 (m,1H), 1.29 - 1.23 (m, 1H), 1.12 (s, 3H), 0.94 (s, 3H), 0.83 (s, 3H). 13 C NMR (151 MHz, CDCl3) δ 210.52, 56.23, 50.25, 44.35, 38.21, 35.56, 27.04, 19.32,18.30, 12.15. HRMS (ESI): C 10 H 16 OS, Neutral mass: 184.0922, Observed ([M+Na]) + :207.0813. Example 56: Preparation of N-(ethanesulfinyl)benzamide (Compound 56)

[0149] In a 10 mL test tube, N-(ethylthio)benzamide (0.0181 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of anhydrous ethanol / water (1 / 1, 0.5 mL) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) was added to the stirred reaction solution, and the mixture was vigorously stirred for 12 hours in open air. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (yield 96%).

[0150] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 9.91 (d, J = 28.5 Hz, 1H), 7.88 (td, J = 7.9, 1.3 Hz, 2H), 7.59 - 7.48 (m, 1H), 7.42 (td, J = 7.8, 3.5 Hz, 2H),3.18 - 3.06 (m, 2H), 1.23 (dt,J = 9.8, 7.5 Hz, 3H). 13 C NMR (151 MHz, CDCl3) δ167.59, 133.14, 131.47, 128.72, 128.26, 128.23, 48.46, 48.42, 7.03. HRMS(ESI): C9H 11 NO2S, Neutral mass: 197.0511, Observed ([M+Na]) + : 220.0310. Example 57: Preparation of Modafinil (Compound 57)

[0151] a) In a 10 mL test tube, add 2-[(diphenylmethyl)thio]acetamide (0.0257 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of anhydrous ethanol / water (1 / 1, 0.5 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution and stir vigorously for 12 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and dichloromethane, combine the organic phases, dry to anhydrous sodium sulfate, and concentrate under reduced pressure to give the oxidation product (yield 99%).

[0152] b) In a 10 mL test tube, add 2-[(diphenylmethyl)thio]acetamide (1.29 g, 5 mmol, 1.0 eq), L-ascorbic acid (1.76 g, 0.2 mmol, 2.0 eq), and a mixed solvent of anhydrous ethanol / water (1 / 1, 25 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.08 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution and stir vigorously for 10 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate, combine the organic phases, concentrate under reduced pressure to give the oxidation product (yield 95%).

[0153] Product characterization: 1H NMR (600 MHz, CDCl3) δ 7.52 - 7.48 (m, 2H), 7.45 - 7.35(m, 8H), 7.05 (s, 1H), 5.73 (s, 1H), 5.22 (s, 1H), 3.48 (d, J = 14.3 Hz, 1H),3.12 (d, J = 14.4 Hz, 1H). Example 58: Preparation of 1-isothiocyanate-3-(methanesulfinyl)propane (Compound 58)

[0154] In a 10 mL test tube, 3-(methylthio)propyl isothiocyanate (0.0147 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of anhydrous ethanol / hydrochloric acid aqueous solution (pH=4) (1 / 1, 0.5 mL) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) was added to the stirred reaction solution, and the mixture was vigorously stirred for 12 hours in open air. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (yield 77%).

[0155] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 3.79 - 3.69 (m, 2H), 2.85 - 2.74(m, 2H), 2.62 (d, J = 1.3 Hz, 3H), 2.24 - 2.16 (m, 2H). Example 59: Preparation of (2S)-2-((tert-Butoxycarbonyl)amino)-4-(methanesulfinyl)butyric acid (Compound 59)

[0156] In a 10 mL test tube, add Boc-L-methionine (0.0249 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of anhydrous ethanol / water (1 / 1, 0.5 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) to the stirred reaction solution, and stir vigorously for 12 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate. Combine the organic phases, dry to anhydrous sodium sulfate, and concentrate under reduced pressure to give the oxidation product (yield 86%).

[0157] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 5.57 (d, J = 50.5 Hz, 1H), 4.41 (d, J = 44.7 Hz, 1H), 2.91 (d, J = 80.3 Hz, 2H), 2.69 (d, J = 29.6 Hz, 3H), 2.47 -2.14 (m, 2H), 1.43 (s, 9H). Example 60: Preparation of diphenyl disulfide (Compound 60)

[0158] In a 10 mL test tube, add thiophene (0.0220 g, 0.2 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 1.0 eq), and a mixed solvent of anhydrous ethanol / water (1 / 1, 0.5 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.0016 g, 0.01 mmol, 0.05 eq) to the stirred reaction solution, and stir vigorously for 12 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate. Combine the organic phases, dry to anhydrous sodium sulfate, and concentrate under reduced pressure to give the oxidation product (yield 83%).

[0159] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 7.51 - 7.47 (m, 4H), 7.29 (dd, J =8.5, 7.0 Hz, 4H), 7.23 - 7.19 (m, 2H). Example 61: Preparation of 4,4'-dichlorodiphenyl disulfide (Compound 61)

[0160] In a 10 mL test tube, add 4-chlorothiophenol (0.0288 g, 0.2 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 1.0 eq), and a mixed solvent of anhydrous ethanol / water (1 / 1, 0.5 mL); stir briefly to dissolve the substrate. At room temperature, add allourea monohydrate (0.0016 g, 0.01 mmol, 0.05 eq) to the stirred reaction solution, and stir vigorously for 12 hours in open air. After the reaction is complete, extract with saturated sodium chloride solution and ethyl acetate. Combine the organic phases, dry to anhydrous sodium sulfate, and concentrate under reduced pressure to give the oxidation product (yield 97%).

[0161] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 7.40 (d, J = 8.6 Hz, 4H), 7.28 (d, J = 8.6 Hz, 4H). Example 62: Preparation of triphenylarsine oxide (compound 62)

[0162] In a 10 mL test tube, triphenylarsine (0.0306 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of 2-methyltetrahydrofuran / water (1 / 1, 1 mL) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) was added to the stirred reaction solution, and the mixture was vigorously stirred for 6 hours in open air. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (yield 96%).

[0163] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 7.71 (d, J = 7.6 Hz, 6H), 7.60 -7.42 (m, 9H). Example 63: Preparation of 2-Naphthol (Compound 63)

[0164] In a 10 mL test tube, 2-naphthoboric acid (0.0171 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of 2-methyltetrahydrofuran / water (1 / 1, 1 mL) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) was added to the stirred reaction solution, and the mixture was vigorously stirred for 10 hours in open air. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (yield 89%).

[0165] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 7.77 (dd, J = 10.5, 8.6 Hz, 2H), 7.69 (dd, J = 8.1, 1.2 Hz, 1H), 7.44 (ddd, J = 8.2, 6.8, 1.3 Hz, 1H), 7.34(ddd, J = 8.1, 6.8, 1.2 Hz, 1H), 7.15 (d, J = 2.5 Hz, 1H), 7.11 (dd, J = 8.8,2.6 Hz, 1H), 5.03 (s, 1H). Example 64: Preparation of 3-methoxyphenol (Compound 64)

[0166] In a 10 mL test tube, 3-methoxyphenylboronic acid (0.0151 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of 2-methyltetrahydrofuran / water (1 / 1, 1 mL) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) was added to the stirred reaction solution, and the mixture was vigorously stirred for 10 hours in open air. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (yield 81%).

[0167] Product characterization: 1H NMR (600 MHz, CDCl3) δ 7.15 (t, J = 8.1 Hz, 1H), 6.54 (dtd, J = 8.3, 1.9, 0.9 Hz, 1H), 6.51 - 6.45 (m, 2H), 3.77 (s, 3H). Example 65: Preparation of phenol (compound 64)

[0168] In a 10 mL test tube, phenylboronic acid (0.0121 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of 2-methyltetrahydrofuran / water (1 / 1, 1 mL) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) was added to the stirred reaction solution, and the mixture was vigorously stirred for 10 hours in open air. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (yield 77%).

[0169] Product characterization: 1 H NMR (600 MHz, CDCl3) δ 7.26 - 7.20 (m, 2H), 6.93 (tt, J =7.3, 1.1 Hz, 1H), 6.85 - 6.80 (m, 2H), 5.31 (s, 1H). Example 66: Preparation of 4-chlorophenol (Compound 64)

[0170] In a 10 mL test tube, 4-chlorophenylboronic acid (0.0156 g, 0.1 mmol, 1.0 eq), L-ascorbic acid (also known as vitamin C) (0.0352 g, 0.2 mmol, 2.0 eq), and a mixed solvent of 2-methyltetrahydrofuran / water (1 / 1, 1 mL) were added; the mixture was briefly stirred to dissolve the substrate. At room temperature, allourea monohydrate (0.0016 g, 0.01 mmol, 0.1 eq) was added to the stirred reaction solution, and the mixture was vigorously stirred for 10 hours in open air. After the reaction was complete, the mixture was extracted with saturated sodium chloride solution and ethyl acetate. The combined organic phases were dried over anhydrous sodium sulfate and concentrated under reduced pressure to give the oxidation product (yield 84%).

[0171] Product characterization:1 H NMR (600 MHz, CDCl3) δ 7.23 - 7.16 (m, 2H), 6.80 - 6.75(m, 2H), 5.50 (s, 1H)。

Claims

1. A method for biomimetic catalytic aerobic oxidation of heteroatom compounds, characterized in that: Oxidation reactions of tertiary phosphine compounds, thioethers, boric acids, arsines, and thiophenols are carried out in the presence of a catalyst, reducing agent, and solvent in air or oxygen to obtain the corresponding oxidation products. Here, the catalyst is a substituted allourea or a monohydrate or polyhydrate of a substituted allourea; The reducing agent is a hydrazine solution, zinc powder, symmetrically structured hansyl ester, ascorbic acid derivative, or crude extract containing ascorbic acid; optionally, the structure of the reducing agent is: ； The solvent is one or more of the following: acetonitrile, acetone, N,N-dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, 2-methyltetrahydrofuran, methanol, ethanol, trifluoroethanol, water, toluene, dichloromethane, chloroform, carbon tetrachloride, dichloroethane, tetrachloroethane, and ethyl acetate, preferably a 2-methyltetrahydrofuran / water or ethanol / water mixed solvent.

2. The method for biomimetic catalytic aerobic oxidation of heteroatom compounds as described in claim 1, wherein the tertiary phosphine compound having the structure shown in formula (I) yields the tertiary phosphine oxide shown in formula (II); the thioether compound having the structure shown in formula (III) yields the sulfoxide compound shown in formula (IV); the triphenylarsine compound having the structure shown in formula (V) yields the structure shown in formula (VI); the arylboronic acid compound having the structure shown in formula (VII) yields the phenolic compound shown in formula (VIII); and the thiophenol compound having the structure shown in formula (IX) yields the disulfide compound shown in formula (X). ； ； ； ； ； The molecular structure of the allourea catalyst is as follows: ； in: R¹, R², R³, R 4 R 5 Substituents attached to S or P atoms In formulas (I), (II), (III), (IV) and the allourea catalyst, R¹, R², R³, R 4 R 5 R 6 R 7 Each group is independently selected from the following groups: hydrogen, C1-C10 alkyl, substituted or unsubstituted aryl, C1-C10 alkoxy, C1-C10 alkyl-substituted thio, halogen, C1-C5 ester, carbonyl, amide, hydroxyl, nitro, carboxyl; wherein, R¹, R², R³, R… 4 R 5 R 6 R 7 They can be the same or different.

3. The method for biomimetic catalytic aerobic oxidation of heteroatom compounds as described in claim 1 or 2, characterized in that: The oxidation reaction is carried out at a temperature of 0–70°C, preferably 25–30°C (room temperature).

4. The method for biomimetic catalytic aerobic oxidation of heteroatom compounds as described in claim 1 or 2, characterized in that: The molar ratio of tertiary phosphine compounds, thioethers, boric acid, arsine compounds, and thiophenol compounds to the albumin catalyst is 1:0.01 to 1, with the ratio of tertiary phosphine compounds, thioethers, boric acid, and arsine compounds preferably being 1:0.1; and the ratio of thiophenol compounds preferably being 1:0.

05.

5. The method for biomimetic catalytic aerobic oxidation of heteroatom compounds as described in claim 1 or 2, characterized in that: The molar ratio of tertiary phosphine compounds, thioethers, boric acid, arsine compounds, and thiophenol compounds to the reducing agent is 1:0.5 to 50, with the ratio of tertiary phosphine compounds, thioethers, boric acid, and arsine compounds preferably being 1:2; and the ratio of thiophenol compounds preferably being 1:

1.

6. The method for biomimetic catalytic aerobic oxidation of heteroatom compounds as described in claim 1 or 2, characterized in that: The concentrations of tertiary phosphine compounds, thioethers, boric acids, arsines, and thiophenols are 0.01–1.0 M, with tertiary phosphine compounds, boric acids, and arsines preferably at 0.1 M; thioether compounds preferably at 0.2 M; and thiophenols preferably at 0.4 M.

7. The method for biomimetic catalytic aerobic oxidation of heteroatom compounds as described in claim 1 or 2, characterized in that: The oxidation time for tertiary phosphine compounds, boric acid, and arsine compounds is preferably 6-10 h; the oxidation time for thioether compounds and thiophenol compounds is preferably 12 h.

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