A method for synthesizing α-thiocyanato-β-dicarbonyl compounds using a photocatalytic oxidation strategy

Abstract

The invention discloses a method for synthesizing α-thiocyanate-β-dicarbonyl compounds using a photocatalytic oxidation strategy, and the specific process is: β-dicarbonyl compounds, thiocyanate and photosensitizer are mixed and dispersed in a solvent, stirred under light source irradiation and air conditions, and the target product α-thiocyanate-β-dicarbonyl compounds is obtained by column chromatography separation or recrystallization after the reaction ends. The effectiveness of the present invention is embodied in that by using cheap and readily available thiocyanate as a thiocyanation reagent, using a green and environmentally friendly photocatalytic oxidation strategy, using molecular oxygen as an oxidant, it is achieved that metal-free, acid-free, alkali-free, and chemical oxidant-free β-dicarbonyl compounds are efficiently α-thiocyanated, and a novel and efficient approach is provided for preparing α-thiocyanated β-dicarbonyl compounds with wide application value. In addition, the reaction post-processing is simple, and the reaction effect can still be maintained when it is amplified to the gram level, with broad production and application prospects.

Description

Technical Field

[0001] The invention belongs to the technical field of organic synthesis, and in particular relates to a method for synthesizing alpha-thiocyanate-beta-dicarbonyl compounds by utilizing a photocatalytic oxidation strategy. Background Art

[0002] Organic compounds containing thiocyanate (SCN) (organic thiocyanates) have a variety of biological activities, such as inhibiting enzyme activity, insecticidal activity, antimicrobial activity, etc. In addition, thiocyanates can be converted into a variety of organic sulfides such as thiols, thioethers, isothiocyanates, sulfur-containing heterocycles, etc. through simple functional group transformation, which has important application value in the fields of medicine, pesticides and materials (Chin.J.Org.Chem.2019,39,287). Therefore, how to introduce SCN groups into organic molecules, especially drug molecular building blocks, is the focus of chemists. The introduction of thiocyanate by direct thiocyanation is the simplest and most efficient, mainly achieved through nucleophilic substitution, electrophilic substitution and free radical reaction types. Traditional chemical methods still have problems such as harsh reaction conditions, difficulty in obtaining raw materials, poor atom economy and many by-products (Chem.Soc.Rev.2016,45,494.). Therefore, the development of green, sustainable, efficient and highly atom-economic C-thiocyanation methods has important theoretical significance and application value. On the other hand, β-dicarbonyl compounds (especially β-ketoesters and β-ketoamides) are a very important class of structural units, and their basic structures are widely found in natural products, fine chemicals, and pesticide and pharmaceutical intermediates (Chem. Rev. 2016, 116, 9375). However, there are few reports on how to achieve efficient C-thiocyanation of β-dicarbonyl compounds and their applications are limited. In 2003, Moriarty used stoichiometric PhICl 2 and Pb(SCN) 2The α-thiocyanation of β-keto esters was achieved, but the reagents were expensive and toxic (J.Org.Chem.2003,66,2019). In 2010, Akamanchi used dimethylsulfonium bromide (BDMS) and ammonium thiocyanate to achieve a series of tandem bromination / thiocyanation reactions of carbonyl and β-dicarbonyl compounds, but stoichiometric dimethylsulfonium bromide was required as a halogenation reagent in this system (Synth.Commun.2010,40,799). Recently, Chen et al. used the electrophilic thiocyanation reagent N-Thiocyanatophthalimide derived from phthalimide to achieve asymmetric thiocyanation of a series of β-keto esters (Org.Lett.2018,20,1600), but the preparation method of the electrophilic reagent was cumbersome, with poor stability and low atom economy, and the substrate was only applicable to large sterically hindered keto esters derived from indane. Therefore, it is urgent to develop a green, efficient and practical thiocyanation method for β-dicarbonyl compounds. Summary of the invention

[0003] The technical problem solved by the present invention is to provide a method for synthesizing α-thiocyanate-β-dicarbonyl compounds by a photocatalytic oxidation strategy. The method uses green and environmentally friendly oxygen as an oxidant and cheap and readily available thiocyanate as a thiocyanation reagent, and realizes efficient and highly selective α-thiocyanation reaction of β-dicarbonyl compounds in the absence of metals and acid and alkali addition, and expands the applicable scope of substrates of β-dicarbonyl compounds, which has very important theoretical value and application prospects.

[0004] The present invention adopts the following technical solution to solve the above technical problems, a method for synthesizing α-thiocyanate-β-dicarbonyl compounds by using a photocatalytic oxidation strategy, the specific process is: β-dicarbonyl compounds, thiocyanate and photosensitizer are mixed and dispersed in a solvent, stirred and reacted under light source irradiation and air conditions, and after the reaction, the target product α-thiocyanate-β-dicarbonyl compounds are obtained by column chromatography separation or recrystallization, wherein thiocyanate is NH 4 SCN, KSCN, NaSCN, LiSCN, CuSCN, Ca(SCN) 2 , CuSCN or AgSCN, the photosensitizer is one or more of Bengal rose red, porphyrin and its derivatives, phthalocyanine and its derivatives, eosin and its derivatives, thioxanthone and its derivatives, methylene blue, diphenyl disulfide and its derivatives or tris(2,2'-bipyridyl)dichlororuthenium and its derivatives, the β-dicarbonyl compound is a compound of formula IIa or a compound of formula IIb, the corresponding α-thiocyanato-β-dicarbonyl compound is a compound of formula Ia or a compound of formula Ib, and the synthetic route of the synthetic process is:

[0005]

[0006] Where R 1 C 1-10 Alkyl, C 3-10 Cycloalkyl, phenyl, substituted phenyl, benzyl, adamantyl or anthracenyl; R 2 For hydrogen, halogen, C 1-10 Alkyl, C 1-10 Alkoxy, C 3-10 Cycloalkyl, phenyl, substituted phenyl or benzyl, R 2 is a mono- or di-substituted, R 3 For hydrogen, halogen, C 1-10 Alkyl, C 1-10 Alkoxy or C 3-10 Cycloalkyl, R 4 C 1-10 Alkyl, C 3-10 Cycloalkyl, phenyl, substituted phenyl, benzyl or naphthyl, R 5 For hydrogen, C 1-10 Alkyl or C 3-10 Cycloalkyl, n is 1 or 2.

[0007] It is further defined that the light source is any visible light, preferably sunlight or a 3W-LED energy-saving lamp.

[0008] It is further defined that the solvent is N,N-dimethylformamide, tetrahydrofuran, acetonitrile, ethanol, methanol, isopropanol, DMSO, dioxane, chloroform, acetone or ether.

[0009] It is further defined that the reaction temperature of the reaction process is -60 to 100°C, preferably 5 to 25°C.

[0010] It is further defined that the dosage of the photosensitizer is 0.1 to 20 mol% of the β-dicarbonyl compound, and the molar ratio of thiocyanate to β-dicarbonyl compound is 2 to 10:1.

[0011] Compared with the prior art, the present invention has the following advantages and beneficial effects: The effectiveness of the present invention is reflected in that by using cheap and readily available thiocyanate as a thiocyanation reagent, utilizing a green and environmentally friendly photocatalytic oxidation strategy, and using molecular oxygen as an oxidant, efficient α-thiocyanation of β-dicarbonyl compounds without metal, acid, alkali, or chemical oxidant addition is achieved, providing a novel and efficient approach for preparing α-thiocyanated β-dicarbonyl compounds with wide application value. In addition, the post-processing of the reaction is simple, and the reaction effect can be maintained when scaled up to the gram level, and has broad production and application prospects.

[0012] In summary, the present invention provides a method for utilizing oxygen in the air as a green oxidant, a low-toxic and low-cost thiocyanate (NH4 SCN, NaSCN, KSCN, etc.) as thiocyanation reagents and cheap and readily available metal-free organic small molecules as photocatalysts have achieved thiocyanation reactions of a series of β-dicarbonyl compounds, which have wide application value. DETAILED DESCRIPTION

[0013] The above contents of the present invention are further described in detail below through examples, but this should not be understood as the scope of the above subject matter of the present invention being limited to the following examples, and all technologies implemented based on the above contents of the present invention belong to the scope of the present invention.

[0014] Example 1

[0015]

[0016] Weigh 0.1 mmol of 1-indanone-2-carboxylic acid methyl ester IIa-1, add 3 times the amount of ammonium thiocyanate and 0.1 times the amount of Bengal rose red, put into a 10 mL single-mouth reaction tube, add 2 mL of acetonitrile, and react under 3W LED white light in air at room temperature with stirring. After reacting for 2 hours, the mixed solution is extracted twice with ethyl acetate, washed once with water, dried over anhydrous sodium sulfate, filtered, and spin-dried. The crude product is separated by column chromatography (petroleum ether: ethyl acetate = 20:1, v / v) to obtain the thiocyanate product 2-thiocyanato-1-indanone-2-carboxylic acid methyl ester Ia-1 (17.1 mg, light yellow solid, yield 69%). 1 H NMR(400MHz,Chloroform-d)δ7.81(dt,J=7.7,1.0Hz,1H),7.68(td,J=7.5,1.2Hz ,1H),7.51–7.36(m,2H),4.12–3.98(m,1H),3.75(s,3H),3.57(d,J=18.0Hz,1H). 13 C NMR (101 MHz, CDCl 3 )δ194.35,166.78,150.86,137.05,132.84,129.02,126.32,126.03,109.25,63.43,54.62,40.36.

[0017] The inventive process implemented in Examples 2-9 is the same as that in Example 1, but the photosensitizers listed in the following table are used instead of the Bengal rose red in Example 1. The results are shown in Table 1.

[0018] Table 1 Preparation of thiocyanate products Ia-1 using different photosensitizers

[0019]

[0020]

[0021] The inventive process implemented in Examples 10-17 is the same as that in Example 5, but the solvents listed in the following table are used instead of the acetonitrile in Example 5. The results are shown in Table 2.

[0022] Table 2 Preparation of thiocyanate products Ia-1 using different solvents

[0023]

[0024] The inventive process implemented in Examples 18-25 is the same as that in Example 5, but the light sources listed in the following table are used instead of the 3W LED white lamp in Example 5. The results are shown in Table 3.

[0025] Table 3 Preparation of thiocyanate product Ia-1 using different light sources

[0026]

[0027] The inventive process implemented in Examples 26-30 is the same as that in Example 18, but the thiocyanates listed in the following table are used instead of the NH 4 SCN, the results are shown in Table 4.

[0028] Table 4 Preparation of thiocyanate products Ia-1 using different thiocyanates

[0029]

[0030] The inventive process implemented in Examples 31-34 is the same as that in Example 18, but the temperatures listed in the following table are used instead of the room temperature in Example 18. The results are shown in Table 5.

[0031] Table 5 Preparation of thiocyanate product Ia-1 using different temperatures

[0032]

[0033] The inventive process implemented in Examples 35-37 is the same as that in Example 32, but the amount of thiocyanamide listed in the following table is used instead of the original amount in Example 32. The results are shown in Table 6.

[0034] Table 6 Preparation of thiocyanate product Ia-1 using different temperatures

[0035]

[0036] Embodiment 38

[0037]

[0038] Weigh 0.1 mmol of 5-bromo-1-indanone-2-carboxylic acid methyl ester IIa-2, add 3 times the amount of ammonium thiocyanate and 0.1 times the amount of methylene blue, put into a 10 mL single-mouth reaction tube, add 2 mL of acetonitrile, and react with stirring at room temperature in air under 3W LED yellow light. After reacting for 6 hours, the mixed solution is extracted twice with ethyl acetate, washed once with water, dried over anhydrous sodium sulfate, filtered, and spin-dried. The crude product is separated by column chromatography (petroleum ether: ethyl acetate = 15:1, v / v) to obtain the thiocyanate product Ia-2 (23.0 mg, white solid, yield 71%). 1 HNMR (400MHz, CDCl 3 )δ7.73–7.61(m,2H),7.58(dd,J=8.3,1.7Hz,1H),4.03(d,J=18.3Hz,1H),3.76(s,3H),3.56(d,J=18.3Hz,1H). 13 CNMR (101MHz, CDCl 3 )δ193.22,166.35,152.21,132.92,132.80,131.71,129.66,127.03,109.03,63.45,54.76,39.92.

[0039] Embodiment 39

[0040]

[0041] Weigh 0.1 mmol of 6-methyl 1-indanone-2-carboxylic acid methyl ester IIa-3, add 3 times the amount of ammonium thiocyanate and 0.1 times the amount of methylene blue, put into a 10 mL single-mouth reaction tube, add 2 mL of acetonitrile, and react with stirring at room temperature in air under 3W LED yellow light. After reacting for 6 hours, the mixed solution is extracted twice with ethyl acetate, washed once with water, dried over anhydrous sodium sulfate, filtered, and spin-dried. The crude product is separated by column chromatography (petroleum ether: ethyl acetate = 25:1, v / v) to obtain the thiocyanate product Ia-3 (16.7 mg, white solid, yield 65%). 1 H NMR (400 MHz, CDCl 3 )δ7.75–7.65(m,1H),7.58(dd,J=7.9,1.7Hz,1H),7.44(d,J=7.9Hz,1H),4.08(d,J=18.0Hz,1H),3.84(s,3H),3.62(d,J=17.9Hz,1H),2.47(s,3H). 13 CNMR (101MHz, CDCl 3)δ194.35,166.89,148.33,139.29,138.38,133.03,125.93,125.83,109.34,63.82,54.56,40.14,21.15.

[0042] Embodiment 40

[0043]

[0044] Weigh 0.1 mmol of 5-methoxy-1-indanone-2-carboxylic acid methyl ester IIa-4, add 3 times the amount of ammonium thiocyanate and 0.1 times the amount of Bengal rose red, put into a 10 mL single-mouth reaction tube, add 2 mL of acetonitrile, and react under 3W LED yellow light in oxygen at room temperature with stirring. After reacting for 12 hours, the mixed solution is extracted twice with ethyl acetate, washed once with water, dried over anhydrous sodium sulfate, filtered, and spin-dried. The crude product is separated by column chromatography (petroleum ether: ethyl acetate = 10:1, v / v) to obtain the thiocyanate product Ia-4 (17.5 mg, white waxy substance, yield 63%). 1 HNMR (400MHz, CDCl 3 )δ7.73(d,J=8.6Hz,1H),6.95(dd,J=8.7,2.2Hz,1H),6.89–6.79(m,1H),4.00(d,J=18.1Hz,1H),3.86(s,3H),3.75(s,3H),3.54(d,J=18.1Hz,1H). 13 C NMR (101 MHz, CDCl 3 )δ192.12,167.17,166.98,154.18,127.82,125.83,117.32,109.54,109.31,64.14,56.01,54.56,40.40.

[0045] Embodiment 41

[0046]

[0047] Weigh 0.1 mmol of 5-chloro-1-indanone-2-carboxylic acid methyl ester IIa-3, add 3 times the amount of ammonium thiocyanate and 0.1 times the amount of methylene blue, put into a 10 mL single-mouth reaction tube, add 2 mL of acetonitrile, and react with stirring at room temperature in air under 3W LED yellow light. After reacting for 4 hours, the mixed solution is extracted twice with ethyl acetate, washed once with water, dried over anhydrous sodium sulfate, filtered, and spin-dried. The crude product is separated by column chromatography (petroleum ether: ethyl acetate = 30:1, v / v) to obtain the thiocyanate product Ia-5 (20.1 mg, white solid, yield 71%). 1 H NMR (400 MHz, CDCl3 )δ7.82(d,J=8.3Hz,1H),7.62–7.42(m,2H),4.09(d,J=18.3Hz,1H),3.83(s,3H),3.63(d,J=18.3Hz,1H). 13 C NMR (101 MHz, CDCl 3 )δ192.93,166.36,152.17,143.94,131.30,129.94,127.02,126.55,109.01,63.53,54.74,40.00.

[0048] Embodiment 42

[0049]

[0050] Weigh 0.1 mmol of 5,6-dimethoxy-1-indanone-2-carboxylic acid methyl ester IIa-6, add 5 times the amount of ammonium thiocyanate and 0.1 times the amount of Bengal rose red, put into a 10 mL single-mouth reaction tube, add 2 mL of acetonitrile, and react under 3W LED yellow light in oxygen at room temperature with stirring. After reacting for 12 hours, the mixed solution is extracted twice with ethyl acetate, washed once with water, dried over anhydrous sodium sulfate, filtered, and spin-dried. The crude product is separated by column chromatography (petroleum ether: ethyl acetate = 8:1, v / v) to obtain the thiocyanate product Ia-6 (18.1 mg, white waxy substance, yield 59%). 1 H NMR (400 MHz, CDCl 3 )δ7.17(s,1H),6.85(s,1H),3.99–3.91(m,4H),3.87(s,3H),3.75(s,3H),3.50(dd,J=17.8,0.8Hz,1H). 13 C NMR (101 MHz, CDCl 3 )δ192.55,167.03,157.52,150.61,147.01,125.63,109.57,106.89,105.55,64.21,56.58,56.26,54.54,40.26.

[0051] Embodiment 43

[0052]

[0053] Weigh 0.1 mmol IIa-7, add 3 times the amount of ammonium thiocyanate and 0.1 times the amount of methylene blue, put into a 10 mL single-mouth reaction tube, add 2 mL of acetonitrile, and react under 3W LED yellow light in air at room temperature with stirring. After reacting for 4 hours, the mixed solution was extracted twice with ethyl acetate, washed once with water, dried over anhydrous sodium sulfate, filtered, and spin-dried. The crude product was separated by column chromatography (petroleum ether: ethyl acetate = 25:1, v / v) to obtain the thiocyanate product Ia-7 (28.1 mg, white solid, yield 85%). 1 H NMR (400 MHz, CDCl 3 )δ7.81(d,J=7.7Hz,1H),7.67(td,J=7.5,1.2Hz,1H),7.51–7.36(m,2H),4.58(t,J=6.1Hz,1H), 4.04(d,J=17.9Hz,1H), 3.61(d,J=17.9Hz,1H), 1.82(dq,J=9.6,6.7Hz,2H), 0.89–0.51(m,12H). 13 C NMR (101 MHz, CDCl 3 )δ194.62,166.22,150.91,136.88,133.16,128.93,126.19,125.86,1 09.59,87.82,64.29,40.62,29.50,29.41,19.46,19.40,17.11,16.87.

[0054] Embodiment 44

[0055]

[0056] Weigh 0.1 mmol IIa-8, add 3 times the amount of ammonium thiocyanate and 0.1 times the amount of methylene blue, put into a 10 mL single-mouth reaction tube, add 2 mL of acetonitrile, and react under 3W LED yellow light in air at room temperature with stirring. After 4 hours of reaction, the mixed solution was extracted twice with ethyl acetate, washed once with water, dried over anhydrous sodium sulfate, filtered, and spin-dried. The crude product was separated by column chromatography (petroleum ether: ethyl acetate = 25:1, v / v) to obtain the thiocyanate product Ia-8 (36.8 mg, light yellow solid, yield 87%). 1 HNMR (400MHz, CDCl 3)δ8.54(s,1H),8.22(dd,J=8.9,1.1Hz,2H),8.09–7.98(m,2H),7.84(d,J=7.7Hz,1H),7.66(dd,J=7.5,1.2Hz,1H),7.62–7.42(m, 5H),7.37(dt,J=7.8,1.0Hz,1H),6.39(d,J=12.5Hz,1H),6.20(d,J=12.5Hz,1H),3.89(d,J=18.0Hz,1H),3.52(d,J=18.0Hz,1H). 13 CNMR (101MHz, CDCl 3 )δ194.29,166.49,150.77,136.82,132.80,131.23,131.04,130.03,129.17,128. 87,127.06,126.18,125.97,125.22,124.15,123.46,109.23,63.77,62.58,40.25.

[0057] Embodiment 45

[0058]

[0059] Weigh 0.1 mmol IIa-9, add 3 times the amount of ammonium thiocyanate and 0.1 times the amount of methylene blue, put into a 10 mL single-mouth reaction tube, add 2 mL of acetonitrile, and react under 3W LED yellow light in air at room temperature with stirring. After 4 hours of reaction, the mixed solution was extracted twice with ethyl acetate, washed once with water, dried over anhydrous sodium sulfate, filtered, and spin-dried. The crude product was separated by column chromatography (petroleum ether: ethyl acetate = 30:1, v / v) to obtain the thiocyanate product Ia-9 (32.3 mg, white colloid, yield 89%). 1 H NMR (400 MHz, CDCl 3 )δ7.81(d,J=7.7Hz,1H),7.66(t,J=7.4Hz,1H),7.56–7.32(m,2H),4.93(t,J=3.5Hz,1H),4.04(d,J =17.9Hz,1H),3.60(d,J=17.9Hz,1H),1.91(t,J=3.6Hz,2H),1.81–1.50(m,10H),1.50–1.31(m,2H). 13 C NMR (101 MHz, CDCl 3)δ194.60,165.45,150.98,136.86,133.13,128.90,126.24,125.83,109.60,81. 55,64.27,40.55,37.06,36.09,36.06,31.67,31.59,31.54,31.50,26.85,26.67.

[0060] Embodiment 46

[0061]

[0062] Weigh 0.1 mmol IIa-11, add 3 times the amount of ammonium thiocyanate and 0.1 times the amount of methylene blue, put into a 10 mL single-mouth reaction tube, add 2 mL of acetonitrile, and react with stirring at room temperature in the air under 3W LED yellow light. After reacting for 4 hours, the mixed solution is extracted twice with ethyl acetate, washed once with water, dried over anhydrous sodium sulfate, filtered, and spin-dried. The crude product is separated by column chromatography (petroleum ether: ethyl acetate = 35:1, v / v) to obtain the thiocyanate product Ia-10 (31.9 mg, white solid, yield 83%). 1 H NMR (400 MHz, CDCl 3 )δ7.82(dd,J=9.1,5.3Hz,1H),7.13(d,J=8.4Hz,2H),3.97(d,J=18.3Hz,1H) ,3.54(d,J=18.2Hz,1H),2.04(dd,J=46.9,3.0Hz,9H),1.55(t,J=2.9Hz,6H). 13 C NMR (101 MHz, CDCl 3 )δ193.24,169.49,166.90,164.40,154.07(d,J=10.7Hz),129.58,129.57,128.34,128.23,117.3 6(d,J=24.0Hz), 113.14(d,J=23.1Hz), 109.67, 86.45, 64.62, 40.88, 40.28, 40.26, 35.79, 30.95.

[0063] Embodiment 47

[0064]

[0065] Weigh 0.1 mmol IIa-11, add 3 times the amount of ammonium thiocyanate and 0.1 times the amount of methylene blue, put into a 10 mL single-mouth reaction tube, add 2 mL of acetonitrile, and react with stirring at room temperature in air under 3W LED yellow light. After reacting for 4 hours, the mixed solution is extracted twice with ethyl acetate, washed once with water, dried over anhydrous sodium sulfate, filtered, and spin-dried. The crude product is separated by column chromatography (petroleum ether: ethyl acetate = 30:1, v / v) to obtain the thiocyanate product Ia-11 (31.2 mg, white solid, yield 82%). 1 H NMR (400 MHz, CDCl 3 )δ7.58(d,J=1.6Hz,1H),7.46(dd,J=7.8,1.7Hz,1H),7.33(d,J=7.8Hz,1H),3.92(d,J=17.9Hz ,1H),3.49(d,J=17.9Hz,1H),2.36(s,3H),2.03(dd,J=43.4,3.0Hz,9H),1.55(d,J=3.1Hz,6H). 13 C NMR (101 MHz, CDCl 3 )δ195.11,164.88,148.53,138.96,138.07,133.33,125.81,125.63,109.90,86.03,64.72,40.88,40.25,35.82,30.94,21.15.

[0066] Embodiment 48

[0067]

[0068] Weigh 0.1 mmol IIa-12, add 3 times the amount of ammonium thiocyanate and 0.1 times the amount of Bengal rose red, put into a 10 mL single-mouth reaction tube, add 2 mL of acetonitrile, and react with stirring at room temperature in air under 3W LED yellow light. After reacting for 4 hours, the mixed solution is extracted twice with ethyl acetate, washed once with water, dried over anhydrous sodium sulfate, filtered, and spin-dried. The crude product is separated by column chromatography (petroleum ether: ethyl acetate = 30:1, v / v) to obtain the thiocyanate product Ia-12 (33.1 mg, white solid, yield 86%). 1 HNMR (400MHz, CDCl 3)δ7.33(d,J=8.4Hz,1H),7.23(dd,J=8.4,2.6Hz,1H),7.21–7.16(m,1H),3.88(d,J=17.7Hz,1 H), 3.79 (s, 3H), 3.46 (d, J = 17.8Hz, 1H), 2.04 (dd, J = 46.9, 3.0Hz, 9H), 1.55 (d, J = 3.3Hz, 6H). 13 C NMR (101 MHz, CDCl 3 )δ194.03,163.77,159.20,143.00,133.40,125.81,125.34,108.81,105.40,85.05,64.02,54.68,39.84,38.94,34.77,29.90.

[0069] Embodiment 49

[0070]

[0071] Weigh 0.1 mmol IIa-13, add 3 times the amount of ammonium thiocyanate and 0.1 times the amount of Bengal rose red, put into a 10 mL single-mouth reaction tube, add 2 mL of acetonitrile, and react under 3W LED yellow light in air at room temperature with stirring. After reacting for 4 hours, the mixed solution is extracted twice with ethyl acetate, washed once with water, dried over anhydrous sodium sulfate, filtered, and spin-dried. The crude product is separated by column chromatography (petroleum ether: ethyl acetate = 20:1, v / v) to obtain the thiocyanate product Ia-13 (19.3 mg, white solid, yield 73%). 1 HNMR (400MHz, CDCl 3 )δ7.99(dd,J=7.9,1.4Hz,1H),7.51(td,J=7.5,1.5Hz,1H),7.35–7.28(m,1H),7.21( d,J=7.7Hz,1H),3.75(s,3H),3.23–2.96(m,3H),2.54(ddd,J=13.8,11.1,5.6Hz,1H). 13 CNMR (101MHz, CDCl 3 )δ188.99,166.85,142.84,135.19,130.11,129.03,128.57,127.56,109.99,65.44,54.18,33.87,26.88.

[0072] Embodiment 50

[0073]

[0074] Weigh 0.1 mmol IIa-14, add 3 times the amount of ammonium thiocyanate and 0.1 times the amount of Bengal rose red, put into a 10 mL single-mouth reaction tube, add 2 mL of acetonitrile, and react under 3W LED yellow light in air at room temperature with stirring. After 4 hours of reaction, the mixed solution was extracted twice with ethyl acetate, washed once with water, dried over anhydrous sodium sulfate, filtered, and spin-dried. The crude product was separated by column chromatography (petroleum ether: ethyl acetate = 20:1, v / v) to obtain the thiocyanate product Ia-14 (20.0 mg, yellow waxy substance, yield 59%). 1 H NMR(400MHz,Chloroform-d)δ8.10(d,J=2.2Hz,1H),7.61(dd,J=8.2,2.2Hz,1H),7.17–6.99(m,1H) ,3.76(s,3H),3.13(dt,J=13.4,3.9Hz,1H),3.06–2.89(m,2H),2.52(ddd,J=13.4,9.6,7.0Hz,1H). 13 C NMR (101 MHz, CDCl 3 )δ187.83,166.56,141.44,137.93,131.55,131.15,130.76,121.57,109.61,65.01,54.31,33.61,26.45.

[0075] Embodiment 51

[0076]

[0077] Weigh 0.1 mmol IIa-15, add 3 times the amount of ammonium thiocyanate and 0.1 times the amount of Bengal rose red, put into a 10 mL single-mouth reaction tube, add 2 mL of acetonitrile, and react with stirring at room temperature in the air under 3W LED yellow light. After 8 hours of reaction, the mixed solution is extracted twice with ethyl acetate, washed once with water, dried over anhydrous sodium sulfate, filtered, and spin-dried. The crude product is separated by column chromatography (petroleum ether: ethyl acetate = 20:1, v / v) to obtain the thiocyanate product Ia-15 (20.1 mg, yellow waxy substance, yield 70%). 1 HNMR(400MHz,Chloroform-d)δ7.42(d,J=2.6Hz,1H),7.17–6.98(m,2H),3.88–3.59(m,6H),3.20–2.89(m,3H),2.52(ddd,J=13.2,10.5,6.0Hz,1H). 13 CNMR (101MHz, CDCl 3)δ188.99,166.88,158.84,135.47,130.85,130.24,123.88,109.99,65.43,55.61,54.16,34.15,26.14.

[0078] Embodiment 52

[0079]

[0080] Weigh 0.1 mmol IIa-16, add 3 times the amount of ammonium thiocyanate and 0.1 times the amount of Bengal rose red, put into a 10 mL single-mouth reaction tube, add 2 mL of acetonitrile, and react under 3W LED yellow light in air at room temperature with stirring. After 8 hours of reaction, the mixed solution was extracted twice with ethyl acetate, washed once with water, dried over anhydrous sodium sulfate, filtered, and spin-dried. The crude product was separated by column chromatography (petroleum ether: ethyl acetate = 20:1, v / v) to obtain the thiocyanate product Ia-16 (30.8 mg, white solid, yield 81%). 1 H NMR(400MHz,Chloroform-d)δ7.96(dd,J=7.9,1.4Hz,1H),7.49(td,J=7.6,1.5Hz,1H),7.30(t,J=7.6Hz,1H),7 .20(d,J=1.8Hz,1H),3.24–2.94(m,3H),2.62–2.33(m,1H),2.03(dd,J=36.9,3.1Hz,9H),1.54(t,J=3.1Hz,6H). 13 C NMR (101 MHz, CDCl 3 )δ189.61,165.10,142.57,134.80,130.61,128.86,128.23,127.46,110.57,85.50,66.33,40.84,35.85,34.08,30.88,27.09.

[0081] Embodiment 53

[0082]

[0083] Weigh 0.1 mmol IIa-17, add 3 times the amount of ammonium thiocyanate and 0.1 times the amount of methylene blue, put into a 10 mL single-mouth reaction tube, add 2 mL of acetonitrile, and react with stirring at room temperature in air under 3W LED yellow light. After reacting for 4 hours, the mixed solution is extracted twice with ethyl acetate, washed once with water, dried over anhydrous sodium sulfate, filtered, and spin-dried. The crude product is separated by column chromatography (petroleum ether: ethyl acetate = 20:1, v / v) to obtain the thiocyanate product Ia-17 (22.1 mg, white solid, yield 78%). 1H NMR (400 MHz, CDCl 3 )δ7.81(d,J=7.7Hz,1H),7.67(td,J=7.5,1.2Hz,1H),7.50–7.38(m,2H),5.03(p,J=6. 3Hz, 1H), 4.01 (d, J = 18.1Hz, 1H), 3.56 (d, J = 18.1Hz, 1H), 1.18 (dd, J = 7.6, 6.3Hz, 6H). 13 C NMR (101 MHz, CDCl 3 )δ194.64,165.77,150.94,136.89,132.97,128.92,126.26,125.93,109.45,72.64,63.52,40.31,21.44,21.34.

[0084] Embodiment 54

[0085]

[0086] Weigh 0.1 mmol IIa-18, add 3 times the amount of ammonium thiocyanate and 0.1 times the amount of methylene blue, put into a 10 mL single-mouth reaction tube, add 2 mL of acetonitrile, and react with stirring at room temperature in air under 3W LED yellow light. After reacting for 4 hours, the mixed solution is extracted twice with ethyl acetate, washed once with water, dried over anhydrous sodium sulfate, filtered, and spin-dried. The crude product is separated by column chromatography (petroleum ether: ethyl acetate = 20:1, v / v) to obtain the thiocyanate product Ia-18 (32.3 mg, white solid, yield 88%). 1 H NMR (400 MHz, CDCl 3 )δ7.80(d,J=7.6Hz,1H),7.65(td,J=7.5,1.2Hz,1H),7.52–7.34(m,2H),3.98(d,J=18 .0Hz,1H),3.55(d,J=18.0Hz,1H),2.03(dd,J=43.8,3.1Hz,9H),1.55(t,J=3.1Hz,6H). 13 C NMR (101 MHz, CDCl 3 )δ195.06,164.74,151.05,136.71,133.18,128.78,126.17,125.82,109.81,86.16,64.36,40.88,40.48,35.81,30.94.

[0087] Embodiment 55

[0088]

[0089] Weigh 0.1 mmol IIa-19, add 3 times the amount of ammonium thiocyanate and 0.1 times the amount of Bengal rose red, put into a 10 mL single-mouth reaction tube, add 2 mL of acetonitrile, and react with stirring at room temperature in air under 3W LED yellow light. After reacting for 4 hours, the mixed solution is extracted twice with ethyl acetate, washed once with water, dried over anhydrous sodium sulfate, filtered, and spin-dried. The crude product is separated by column chromatography (petroleum ether: ethyl acetate = 20:1, v / v) to obtain the thiocyanate product Ia-18 (39.9 mg, white solid, yield 87%). 1 HNMR (400MHz, CDCl 3 )δ8.08(d,J=2.2Hz,1H),7.59(dd,J=8.2,2.2Hz,1H),7.10(d,J=8.2Hz,1H),3 .07–2.99(m,3H),2.53–2.43(m,1H),2.13–1.89(m,9H),1.56(d,J=3.1Hz,6H). 13 C NMR (101 MHz, CDCl 3 )δ188.41,164.80,141.25,137.58,132.03,130.82,130.64,121.46,110.20,85.93,65.91,40.86,35.82,33.84,30.90,26.67.

[0090] Embodiment 56

[0091]

[0092] Weigh 0.1 mmol IIa-20, add 3 times the amount of ammonium thiocyanate and 0.1 times the amount of Bengal rose red, put into a 10 mL single-mouth reaction tube, add 2 mL of acetonitrile, and react under 3W LED yellow light in air at room temperature with stirring. After reacting for 4 hours, the mixed solution is extracted twice with ethyl acetate, washed once with water, dried over anhydrous sodium sulfate, filtered, and spin-dried. The crude product is separated by column chromatography (petroleum ether: ethyl acetate = 20:1, v / v) to obtain the thiocyanate product Ia-20 (34.5 mg, white solid, yield 84%). 1 H NMR (400 MHz, CDCl 3 )δ7.42(d,J=2.6Hz,1H),7.17–6.98(m,2H),3.88–3.59(m,6H),3.20–2.89(m,3H),2.52(ddd,J=13.2,10.5,6.0Hz,1H). 13 C NMR (101 MHz, CDCl 3)δ188.99,166.88,158.84,135.47,130.85,130.24,123.88,109.99,65.43,55.61,54.16,34.15,26.14.

[0093] Embodiment 57

[0094]

[0095] Weigh 0.1 mmol IIb-1, add 3 times the amount of ammonium thiocyanate and 0.1 times the amount of Bengal rose red, put into a 10 mL single-mouth reaction tube, add 2 mL of acetonitrile, and react under 3W LED white light in air at room temperature with stirring. After reacting for 4 hours, the mixed solution was extracted twice with ethyl acetate, washed once with water, dried over anhydrous sodium sulfate, filtered, and spin-dried. The crude product was separated by column chromatography (petroleum ether: ethyl acetate = 35:1, v / v) to obtain the thiocyanate product Ib-1 (19.4 mg, white solid, yield 63%). 1 H NMR (400 MHz, CDCl 3 )δ7.78(d,J=7.7Hz,1H),7.70–7.59(m,1H),7.54–7.35(m,5H),7.31–7.23(m,2H),4.12(d,J=17.8Hz,1H),3.47(d,J=17.8Hz,1H). 13 C NMR (101 MHz, CDCl 3 )δ198.76,173.57,159.34,151.18,137.16,135.443,132.07,129.87,127.36,126.49,125.48,61.36,38.40.

[0096] The inventive process implemented in Examples 58-61 is the same as that in Example 57, but the photosensitizers listed in the following table are used instead of the Rose Bengal in Example 57. The results are shown in Table 7.

[0097] Table 7 Preparation of thiocyanate product Ib-1 using different photosensitizers

[0098]

[0099] The inventive process implemented in Examples 62-66 is the same as that in Example 61, but the solvents listed in the following table are used instead of the acetonitrile in Example 61. The results are shown in Table 8.

[0100] Table 8 Preparation of thiocyanate product Ib-1 using different solvents

[0101]

[0102] Embodiment 67

[0103]

[0104] Weigh 0.1 mmol IIb-2, add 3 times the amount of ammonium thiocyanate and 0.1 times the amount of rhodamine 6G, put into a 10 mL single-mouth reaction tube, add 2 mL of ethanol, and react with stirring at room temperature in air under 3W LED yellow light. After 3 hours of reaction, the mixed solution was extracted twice with ethyl acetate, washed once with water, dried over anhydrous sodium sulfate, filtered, and spin-dried. The crude product was separated by column chromatography (petroleum ether: ethyl acetate = 15:1, v / v) to obtain the thiocyanate product Ib-2 (25.4 mg, light yellow solid, yield 71%). 1 H NMR (400 MHz, CDCl 3 )δ8.09–7.99(m,1H),7.93(d,J=8.2Hz,1H),7.84(dd,J=9.7,8.1Hz,2H),7.66(td,J=7.5,1.2Hz,1H),7.60(ddd ,J=8.3,6.8,1.3Hz,1H),7.55–7.46(m,3H),7.46–7.38(m,2H),4.20(d,J=17.8Hz,1H),3.56(d,J=17.8Hz,1H). 13 C NMR (101 MHz, CDCl 3 )δ197.94,171.35,159.88,152.21,136.71,134.63,132.95,130.85,129.66,128.7 8,128.48,128.17,127.23,127.08,126.46,125.96,125.39,122.23,63.07,38.88.

[0105] Embodiment 68

[0106]

[0107] Weigh 0.1 mmol IIb-3, add 3 times the amount of ammonium thiocyanate and 0.1 times the amount of rhodamine 6G, put into a 10 mL single-mouth reaction tube, add 2 mL of ethanol, and react under 3 W LED white light in air at room temperature with stirring. After reacting for 3 hours, the mixed solution was extracted twice with ethyl acetate, washed once with water, dried over anhydrous sodium sulfate, filtered, and spin-dried. The crude product was separated by column chromatography (petroleum ether: ethyl acetate = 15:1, v / v) to obtain the thiocyanate product Ib-3 (18.9 mg, white solid, yield 69%). 1 H NMR (400 MHz, CDCl 3)δ7.86(d,J=7.7Hz,1H),7.75(td,J=7.6,1.2Hz,1H),7.58–7.43(m,2H),7.07(d,J=7.5Hz,1H),4.32(d,J=18 .8Hz,1H),4.09(dp,J=7.7,6.5Hz,1H),3.30(d,J=18.8Hz,1H),1.30(d,J=6.6Hz,3H),1.18(d,J=6.6Hz,3H). 13 C NMR (101 MHz, CDCl 3 )δ198.00,163.07,150.48,137.35,132.78,128.88,126.54,125.82,108.61,57.06,43.00,37.51,22.43,22.30.

[0108] Embodiment 69

[0109]

[0110] Weigh 0.1 mmol IIb-4, add 3 times the amount of ammonium thiocyanate and 0.1 times the amount of rhodamine 6G, put into a 10 mL single-mouth reaction tube, add 2 mL of ethanol, and react under 3 W LED white light in air at room temperature with stirring. After reacting for 3 hours, the mixed solution was extracted twice with ethyl acetate, washed once with water, dried over anhydrous sodium sulfate, filtered, and spin-dried. The crude product was separated by column chromatography (petroleum ether: ethyl acetate = 15:1, v / v) to obtain the thiocyanate product Ib-4 (22.6 mg, white solid, yield 72%). 1 HNMR (400MHz, CDCl 3 )δ7.84–7.57(m,2H),7.52–7.34(m,2H),7.10(d,J=8.1Hz,1H),4.24(d,J=18.8Hz,1H),3.82–3.63(m,1 H),3.22(d,J=18.9Hz,1H),2.03–1.86(m,1H),1.85–1.59(m,3H),1.58–1.46(m,1H),1.37–1.13(m,5H). 13 C NMR (101 MHz, CDCl 3 )δ198.06,163.03,150.42,137.34,132.79,128.88,126.55,125.83,108.67,56.94,49.49,37.47,32.53,32.42,25.39,24.51.

[0111] Embodiment 70

[0112]

[0113] Weigh 0.1 mmol IIb-5, add 3 times the amount of ammonium thiocyanate and 0.1 times the amount of rhodamine 6G, put into a 10 mL single-mouth reaction tube, add 2 mL of ethanol, and react under 3W LED white light in air at room temperature with stirring. After reacting for 3 hours, the mixed solution was extracted twice with ethyl acetate, washed once with water, dried over anhydrous sodium sulfate, filtered, and spin-dried. The crude product was separated by column chromatography (petroleum ether: ethyl acetate = 20:1, v / v) to obtain the thiocyanate product Ib-5 (25.1 mg, white solid, yield 78%). 1 H NMR (400 MHz, CDCl 3 )δ7.85(d,J=7.7Hz,1H),7.70(dd,J=7.5,1.2Hz,1H),7.57–7.42(m,2H),7.32(d,J=8.0 Hz,2H),7.25–7.15(m,2H),4.19(d,J=17.7Hz,1H),3.53(d,J=17.8Hz,1H),2.40(s,3H). 13 CNMR (101MHz, CDCl 3 )δ197.62,171.66,159.31,152.03,139.81,136.53,133.12,130.48,128.67,127.90,126.39,125.81,62.60,39.13,21.33.

[0114] Embodiment 71

[0115]

[0116] Weigh 0.1 mmol IIb-6, add 3 times the amount of ammonium thiocyanate and 0.1 times the amount of rhodamine 6G, put into a 10 mL single-mouth reaction tube, add 2 mL of ethanol, and react under 3W LED white light in air at room temperature with stirring. After reacting for 3 hours, the mixed solution was extracted twice with ethyl acetate, washed once with water, dried over anhydrous sodium sulfate, filtered, and spin-dried. The crude product was separated by column chromatography (petroleum ether: ethyl acetate = 20:1, v / v) to obtain the thiocyanate product Ib-6 (25.1 mg, white solid, yield 78%). 1 HNMR (400MHz, CDCl 3)δ8.54(s,1H),7.75(d,J=7.7Hz,1H),7.62(td,J=7.5,1.2Hz,1H),7.49–7.42(m,1H ),7.40–7.36(m,2H),6.87–6.63(m,2H),3.83–3.61(m,4H),3.13(d,J=16.7Hz,1H). 13 C NMR (101 MHz, CDCl 3 )δ203.15,167.88,156.65,153.01,136.52,133.72,130.07,128.20,126.39,125.24,121.31,114.14,82.70,55.48,40.87.

[0117] Embodiment 72

[0118]

[0119] Weigh 0.1 mmol IIb-7, add 3 times the amount of ammonium thiocyanate and 0.1 times the amount of rhodamine 6G, put into a 10 mL single-mouth reaction tube, add 2 mL of ethanol, and react under 3W LED white light in air at room temperature with stirring. After 3 hours of reaction, the mixed solution was extracted twice with ethyl acetate, washed once with water, dried over anhydrous sodium sulfate, filtered, and spin-dried. The crude product was separated by column chromatography (petroleum ether: ethyl acetate = 20:1, v / v) to obtain the thiocyanate product Ib-7 (24.3 mg, light yellow solid, yield 76%). 1 H NMR (400 MHz, CDCl 3 )δ7.75(d,J=7.7Hz,1H),7.62(td,J=7.5,1.2Hz,1H),7.47–7.30(m,4H),7.29–7. 16(m,3H),4.91(q,J=14.6Hz,2H),4.01(d,J=17.9Hz,1H),3.37(d,J=17.9Hz,1H). 13 C NMR (101 MHz, CDCl 3 )δ197.54,172.26,157.85,152.02,136.50,135.33,133.29,128.63,128.61,128.02,127.80,126.33,125.78,63.09,46.08,39.44.

[0120] Embodiment 73

[0121]

[0122] Weigh 0.1 mmol IIb-8, add 3 times the amount of ammonium thiocyanate and 0.1 times the amount of rhodamine 6G, put into a 10 mL single-mouth reaction tube, add 2 mL of ethanol, and react under 3 W LED white light in air at room temperature with stirring. After reacting for 3 hours, the mixed solution was extracted twice with ethyl acetate, washed once with water, dried over anhydrous sodium sulfate, filtered, and spin-dried. The crude product was separated by column chromatography (petroleum ether: ethyl acetate = 20:1, v / v) to obtain the thiocyanate product Ib-8 (29.3 mg, white solid, yield 76%). 1 H NMR (400 MHz, CDCl 3 )δ8.67(s,1H),7.72(ddd,J=36.8,7.7,1.0Hz,2H),7.50–7.39(m,2H),7.30–7.20 (m,3H),7.11–6.97(m,1H),3.75(d,J=17.3Hz,1H),3.03(dd,J=17.2,0.9Hz,1H). 13 C NMR (101 MHz, CDCl 3 )δ202.62,168.02,152.69,139.13,136.70,135.69,129.88,129.07,124.97,123.94,121.75,119.75,82.22,41.87.

[0123] Embodiment 74

[0124]

[0125] Weigh 0.1 mmol IIb-9, add 3 times the amount of ammonium thiocyanate and 0.1 times the amount of rhodamine 6G, put into a 10 mL single-mouth reaction tube, add 2 mL of ethanol, and react under 3 W LED white light in air at room temperature with stirring. After reacting for 3 hours, the mixed solution was extracted twice with ethyl acetate, washed once with water, dried over anhydrous sodium sulfate, filtered, and spin-dried. The crude product was separated by column chromatography (petroleum ether: ethyl acetate = 20:1, v / v) to obtain the thiocyanate product Ib-9 (30.3 mg, white solid, yield 79%). 1 HNMR (400MHz, CDCl 3 )δ8.65(s,1H),7.67–7.39(m,5H),7.25(t,J=7.9Hz,2H),7.12–7.01(m,1H),3.79(d,J=16.8Hz,1H),3.11(d,J=16.8Hz,1H). 13 C NMR (101 MHz, CDCl 3)δ201.89,167.81,154.37,136.75,132.49,132.28,131.93,129.76,129.09,126.26,124.94,119.69,82.83,40.53.

[0126] Embodiment 75

[0127]

[0128] Weigh 0.1 mmol IIb-10, add 3 times the amount of ammonium thiocyanate and 0.1 times the amount of rhodamine 6G, put into a 10 mL single-mouth reaction tube, add 2 mL of ethanol, and react under 3W LED white light in air at room temperature with stirring. After reacting for 3 hours, the mixed solution was extracted twice with ethyl acetate, washed once with water, dried over anhydrous sodium sulfate, filtered, and spin-dried. The crude product was separated by column chromatography (petroleum ether: ethyl acetate = 20:1, v / v) to obtain the thiocyanate product Ib-10 (26.0 mg, white solid, yield 81%). 1 H NMR (400 MHz, CDCl 3 )δ8.04(d,J=7.9Hz,1H),7.60–7.05(m,8H),3.21–3.02(m,3H),2.64–2.42(m,1H). 13 C NMR (101 MHz, CDCl 3 )δ190.36,172.29,158.12,142.44,134.86,129.80,129.68,129.56,129.01,128.88,128.31,127.65,64.09,32.03,26.24.

[0129] Embodiment 76

[0130]

[0131] Weigh 0.1 mmol IIb-11, add 3 times the amount of ammonium thiocyanate and 0.1 times the amount of rhodamine 6G, put into a 10 mL single-mouth reaction tube, add 2 mL of ethanol, and react under 3W LED white light in air at room temperature with stirring. After reacting for 3 hours, the mixed solution was extracted twice with ethyl acetate, washed once with water, dried over anhydrous sodium sulfate, filtered, and spin-dried. The crude product was separated by column chromatography (petroleum ether: ethyl acetate = 20:1, v / v) to obtain the thiocyanate product Ib-11 (24.2 mg, white solid, yield 76%). 1 HNMR (400MHz, CDCl 3)δ8.00(dd,J=8.0,1.4Hz,1H),7.52(td,J=7.5,1.5Hz,1H),7.35–7.16(m,2H),6.45(d,J=6.0Hz,1H),3.38–3.05(m,4H),2.9 8(dt,J=17.5,4.7Hz,1H),2.55(ddd,J=13.6,10.5,4.7Hz,1H),1.51–1.33(m,2H),1.31–1.12(m,2H),0.82(t,J=7.3Hz,3H). 13 C NMR (101 MHz, CDCl 3 )δ192.42,163.70,144.22,135.69,129.80,129.08,128.74,127.45,109.60,63.53,40.32,32.91,31.16,26.73,19.90,13.68.

[0132] Embodiment 77

[0133] Gram-scale scale-up experiment of α-thiocyanate of β-ketoester

[0134]

[0135] Weigh 1 mmol IIa-1 (1.90 g), add 3 times the amount of ammonium thiocyanate and 0.1 times the amount of methylene blue, put into a 100 mL single-mouth reaction tube, add 50 mL of acetonitrile, and react under 25 W LED white light in air at room temperature with stirring. After 8 hours of reaction, the mixed solution was extracted twice with ethyl acetate, washed once with water, dried over anhydrous sodium sulfate, filtered, and spin-dried. The crude product was separated by column chromatography (petroleum ether: ethyl acetate = 25:1, v / v) to obtain the thiocyanate product Ia-7 (1.84 g, light yellow solid, yield 74%).

[0136] The above embodiments describe the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for illustrating the principles of the present invention. Without departing from the scope of the principles of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of protection of the present invention.

Claims

1. A method for synthesizing α-thiocyanato-β-dicarbonyl compounds using a photocatalytic oxidation strategy, characterized in that The specific process is: β-dicarbonyl compounds, thiocyanate and photosensitizer are mixed and dispersed in a solvent, stirred and reacted under light source irradiation and air conditions, and after the reaction, column chromatography separation or recrystallization is performed to obtain the target product α-thiocyanate-β-dicarbonyl compounds, wherein the thiocyanate is one or more of NH4SCN, KSCN, NaSCN, LiSCN, CuSCN, Ca(SCN)2, CuSCN or AgSCN, the photosensitizer is one or more of Bengal rose red, porphyrin, phthalocyanine, eosin, thioxanthone, methylene blue, diphenyl disulfide or tris(2,2'-bipyridine)ruthenium dichloride, the β-dicarbonyl compound is a compound of formula IIa or a compound of formula IIb, and the corresponding α-thiocyanate-β-dicarbonyl compound is a compound of formula Ia or a compound of formula Ib. The synthetic route of the synthetic process is: Where R1 is C 1-10 Alkyl, C 3-10 Cycloalkyl, phenyl, substituted phenyl, benzyl, adamantyl or anthracenyl; R2 is hydrogen, halogen, C 1-10 Alkyl, C 1-10 Alkoxy, C 3-10 Cycloalkyl, phenyl, substituted phenyl or benzyl, R2 is monosubstituted or disubstituted, R3 is hydrogen, halogen, C 1-10 Alkyl, C 1-10 Alkoxy or C 3-10 Cycloalkyl, R3 is monosubstituted or disubstituted, R4 is C 1-10 Alkyl, C 3-10 Cycloalkyl, phenyl, substituted phenyl, benzyl or naphthyl, R5 is hydrogen, C 1-10 Alkyl or C 3-10 Cycloalkyl, n is 1 or 2.

2. The method for synthesizing α-thiocyanate-β-dicarbonyl compounds using a photocatalytic oxidation strategy according to claim 1, characterized in that: The light source is any visible light.

3. The method for synthesizing α-thiocyanate-β-dicarbonyl compounds using a photocatalytic oxidation strategy according to claim 1, characterized in that: The light source is sunlight or a 3W-LED energy-saving lamp.

4. The method for synthesizing α-thiocyanate-β-dicarbonyl compounds using a photocatalytic oxidation strategy according to claim 1, characterized in that: The solvent is N,N-dimethylformamide, tetrahydrofuran, acetonitrile, ethanol, methanol, isopropanol, DMSO, dioxane, chloroform, acetone or ether.

5. The method for synthesizing α-thiocyanate-β-dicarbonyl compounds using a photocatalytic oxidation strategy according to claim 1, characterized in that: The reaction temperature of the reaction process is 5~25℃.

6. The method for synthesizing α-thiocyanato-β-dicarbonyl compounds using a photocatalytic oxidation strategy according to claim 1, characterized in that: The dosage of the photosensitizer is 0.1-20 mol% of the β-dicarbonyl compound, and the molar ratio of thiocyanate to the β-dicarbonyl compound is 2-10:1.

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