Method for synthesizing alpha-aryl ketone compound from aryl allyl amide

Abstract

The invention discloses a method for synthesizing an alpha-aryl ketone compound from aryl allyl amide. The method comprises the following steps: by taking a boron-carbon-nitrogen material prepared by a high-temperature molten salt method as a photocatalyst, adding alpha, alpha-diaryl allyl amide, a fluorine-containing free radical precursor and alkali into a reaction container under the conditions of normal temperature and normal pressure, directly adding a reaction solvent, and then reacting in a nitrogen atmosphere and under the irradiation of visible light. And separating and purifying the reaction product to obtain the alpha-aryl ketone compound. The operation method is simple, the catalytic effect is good, the method can be carried out under visible light, the condition is mild, the cost is low, the actual production requirement is met, and the great application potential is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of photocatalytic organic synthesis, and specifically relates to a method for synthesizing alpha-aryl ketone compounds from aryl allyl amides. Background Art

[0002] As one of the most important synthetic raw materials in the world, olefins are widely distributed in nature. Since olefins can be used to extend carbon chains and introduce various functional groups through addition reactions, they occupy a core position in organic synthesis. At present, organic chemists have successfully developed several valuable methods for the difunctionalization of olefins through photoredox catalysis for the preparation of valuable compounds. Among them, α-aryl ketone compounds are key components of many biologically active natural products and synthetic drugs, and have a wide range of medicinal and biological activities, such as anti-inflammatory, anti-depressant, and anti-tumor. Using cheap and readily available polyfluorinated compounds as raw materials, a series of fluorinated α-aryl ketone compounds with application prospects can be synthesized.

[0003] In 2015, Xia's group completed the aryl alkylation of allylic alcohol for the first time through photoredox catalysis, and obtained a series of α-aryl-β-alkylated ketone products (Chem. Commun. 2015, 51, 4910-4913). This method has the characteristics of simple operation, good functional group tolerance, and high yield under mild conditions. In the same year, Zhu's group reported visible light-promoted carbon difluoroalkylation of allylic alcohol, and obtained a series of difluoro 1,5-dicarbonyl compounds through free radical addition and 1,2-aryl migration (Chem. Commun. 2015, 51, 7222-7225). In 2021, Shi's group reported an effective method for photocatalytic perfluoroalkylation of vinyl-substituted all-carbon quaternary centers involving 1,2-aryl migration (Angewandte Chemie International Edition, 2021, 60 (1): 186-190.). This strategy selects a class of olefins with a vinyl-substituted all-carbon four-member center, and uses fac-Ir(ppy)3, visible light, and fluoroalkyl halides to generate valuable multi-substituted perfluoroalkylated compounds in one step. However, there are few reports on the synthesis of α-aryl ketone compounds from aryl allyl amides, and the existing synthesis of fluorinated aryl ketone compounds mainly uses transition metal or homogeneous noble metal catalysts and unstable and excessive strong oxidants or free radical initiators, which have problems such as high reaction cost and harsh reaction conditions. This requires further in-depth research and development of economical and green photocatalytic strategies with mild reaction conditions to synthesize high value-added polyfluoroalkyl ketone compounds. Summary of the invention

[0004] In order to solve the shortcomings and deficiencies of the above prior art, the present invention provides a method for synthesizing α-aryl ketone compounds from aryl allyl amides, wherein the amide is removed through a 1,2-aryl migration process, thereby realizing the fluoroalkylation reaction of the aromatic group. The catalytic system of the present invention does not require the addition of a strong oxidant or a free radical initiator, and can be applied to various symmetrical and asymmetrical α, α-diaryl allyl amides. The operating method of the present invention is simple, has a good catalytic effect, can be carried out under visible light, has mild conditions, and has low cost.

[0005] To achieve the above object, the present invention adopts the following technical solution:

[0006] The preparation method of the non-metallic boron carbon nitrogen (BCN) photocatalyst used comprises the following steps:

[0007] (a) grinding boric acid, urea and glucose in a mass ratio of (1-2):(1-4):(1-10) uniformly;

[0008] (b) The mixed powder obtained by grinding in step (a) is transferred to a tubular furnace, heated to 1000-1250° C. in an ammonia atmosphere, calcined for 1-5 h, then cooled to room temperature, ground, washed, and dried to obtain boron carbon nitrogen nanosheets.

[0009] The method for synthesizing α-aryl ketone compounds from aryl allyl amides comprises the following steps: directly adding a photocatalyst, a base, a fluorine-containing free radical precursor and α, α-diaryl allyl amide or its derivatives into an organic solvent, charging with nitrogen gas, stirring and reacting for 20-24 hours at room temperature, normal pressure and visible light illumination conditions, and then separating and purifying to obtain α-aryl ketone compounds;

[0010] The boron carbon nitrogen photocatalyst can be used for photocatalytic aromatic migration to achieve aromatic alkylation of olefins, that is, under the conditions of room temperature, normal pressure and visible light illumination, ethyl bromodifluoroacetate is used as a fluorine source, and the boron carbon nitrogen photocatalytic material is used to remove the amide from α, α-diaryl allyl amide through a 1,2-aromatic migration process, thereby achieving an aromatic fluoroalkylation reaction;

[0011] The general structural formula of the reaction substrate is shown in formula (I) or formula (II):

[0012]

[0013] Among them, R1 is hydrogen, substituted methyl, ethyl, halogen, trifluoromethyl, methoxy, thiomethyl, trifluoromethoxy, tert-butyl; R2 is hydrogen, alkyl or halogen; R3 is hydrogen or alkoxy; R4 is hydrogen, alkyl, halogen or alkoxy; R5 is hydrogen or alkyl; R6 is hydrogen, cycloalkyl, thiophene or benzodioxolane.

[0014] Based on the above solution, the present invention can also be improved as follows.

[0015] Furthermore, the molar ratio of the photocatalyst, the base, the fluorine-containing free radical precursor and the α,α-diaryl allyl amide used is (1-5):(1-3):(2-4):(1-2).

[0016] Furthermore, the photocatalyst is a non-metallic boron carbon nitrogen (BCN) photocatalyst.

[0017] Furthermore, the fluorine-containing free radical precursor is one of ethyl bromodifluoroacetate, perfluoroiodide and perfluorobromide.

[0018] Furthermore, the base is hydrogen phosphate, phosphate, carbonate, hydrogen carbonate or an organic base.

[0019] Furthermore, the solvent is one of MeCN, DMF, DMA, THF and DMSO.

[0020] Furthermore, the pressure of N2 in the reaction container is normal pressure; the distance between the light source and the reaction container is 0.5-5 cm, the wavelength of the light is 390-450 nm, and the power of the light source is 3-50 W.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] The catalytic system of the present invention does not need to add a strong oxidant or a free radical initiator, and can be applied to various symmetrical and asymmetrical α, α-diaryl allyl amides. The operation method of the present invention is simple, the catalytic effect is good, it can be carried out under visible light, the conditions are mild, and the cost is low. DETAILED DESCRIPTION

[0023] The specific implementation modes of the present invention are described in detail below with reference to the embodiments.

[0024] The preparation method of the non-metallic boron carbon nitrogen (BCN) photocatalyst used in the following examples comprises the following steps:

[0025] (a) grinding boric acid, urea and glucose in a mass ratio of 1:1:1;

[0026] (b) The mixed powder obtained by grinding in step (a) is transferred to a tube furnace, heated to 1000° C. in an ammonia atmosphere, calcined for 1 h, then cooled to room temperature, ground, washed, and dried to obtain boron carbon nitrogen nanosheets.

[0027] Example 1

[0028] A method for synthesizing α-aryl ketone compounds from aryl allyl amides, the synthesis reaction equation is shown in (1-1):

[0029]

[0030] The synthesis method comprises the following steps:

[0031] The boron carbon nitrogen photocatalyst (10 mg), the reaction substrate α, α-diphenylallylamide (31.3 mg, 0.1 mmol, 1 equiv), and the base K2HPO4 (26.1 mg, 0.15 mmol, 1.5 equiv) were added in sequence to a 10 mL Schlenk reaction tube equipped with a stirrer, followed by the addition of the fluorinated free radical precursor ethyl bromodifluoroacetate (32 uL, 0.25 mmoL, 0.25 equiv), the solvent DMF (1 mL, 0.1 M) and 10 uL H2O, and then the liquid was frozen with liquid nitrogen. After the solvent became solid, the reaction tube was evacuated with a double-row tube to replace it with a N2 atmosphere, and the evacuation was repeated three times, and then the reaction tube was thawed and sealed. The reaction tube was fixed in a glass container with condensed water reflux, the reaction temperature was maintained at 25-30°C, the speed of the stirrer used for the reaction was adjusted to 700 r / min, a 3W blue LED lamp (wavelength of about 450 nm) was used for irradiation at a distance of 0.5 cm, and the reaction was stirred for 20 h.

[0032] After the reaction, the reaction solution was extracted with ethyl acetate, washed three times with 30 ml of saturated brine, the organic phases were combined, dried over anhydrous Na2SO4, filtered, and the solvent was distilled under reduced pressure to obtain a crude product, and finally purified by column chromatography with a mixed solvent of petroleum ether and ethyl acetate in a volume ratio of 15:1 to obtain ethyl 2,2-difluoro-5-oxo-4,5-diphenylpentanoate Colorless oil [1] , with a yield of 76% (252 mg). 1 H NMR(600MHz,Chloroform-d)δ7.97–7.92(m,2H),7.48(t,J=7.4Hz,1H),7.38(t,2H),7.31–7.23(m,4H),7.22–7.18(m,1H),4. 95(dd,J=8.0,5.0Hz,1H),4.20–4.10(m,1H),4.09–4.01(m,1H),3.37–3.19(m,1H),2.64–2.44(m,1H),1.21(t,J=7.2Hz,3H). 13C NMR (151 MHz, Chloroform-d) δ 197.39, 163.86 (d, J = 32.0 Hz), 137.90, 135.93, 133.29, 129.30, 128.91, 128.69, 128.35, 127.77, 115.38, 62.99, 47.00 (t), 38.42 (d, J = 23.1 Hz), 13.89–13.71 (m). Example 2

[0033] A method for synthesizing α-aryl ketone compounds from aryl allyl amides, the synthesis reaction equation is shown in (1-2):

[0034]

[0035] The synthesis method comprises the following steps:

[0036] The boron carbon nitrogen photocatalyst (10 mg), the reaction substrate N-(1,1-bis(4-fluorophenyl)allyl)benzamide (34.9 mg, 0.1 mmol, 1 equiv), and the base K2HPO4 (26.1 mg, 0.15 mmol, 1.5 equiv) were added in sequence to a 10 mL Schlenk reaction tube equipped with a stirrer, followed by the addition of the fluorinated free radical precursor ethyl bromodifluoroacetate (32 uL, 0.25 mmoL, 0.25 equiv), the solvent DMF (1 mL, 0.1 M) and 10 uL H2O, and then the liquid was frozen with liquid nitrogen. After the solvent became solid, the reaction tube was evacuated with a double-row tube to replace it with a N2 atmosphere, and the evacuation was repeated three times, and then the reaction tube was thawed and sealed. The reaction tube was fixed in a glass container with condensed water reflux, the reaction temperature was maintained at 25-30°C, the speed of the stirrer used for the reaction was adjusted to 700 r / min, a 3W blue LED lamp (wavelength of about 450 nm) was used for irradiation at a distance of 0.5 cm, and the reaction was stirred for 20 h.

[0037] After the reaction, the reaction solution was extracted with ethyl acetate, washed three times with 30 ml of saturated brine, the organic phases were combined, dried over anhydrous Na2SO4, filtered, and the solvent was distilled under reduced pressure to obtain a crude product, and finally purified by column chromatography with a mixed solvent of petroleum ether and ethyl acetate in a volume ratio of 16:1 to obtain ethyl 2,2-difluoro-4,5-bis(4-fluorophenyl)-5-oxopentanoate Colorless oil [2] , with a yield of 56% (206 mg). 1H NMR(600MHz,Chloroform-d)δ8.02–7.88(m,2H),7.26–7.22(m,2H),7.09–7.03(m,2H),6.97(t,J=8.6Hz,2H),4.89(dd ,J=7.8,5.0Hz,1H),4.23–4.14(m,1H),4.13–4.05(m,1H),3.28–3.15(m,1H),2.55–2.42(m,1H),1.24(t,J=7.2Hz,3H). 13 C NMR(151MHz,Chloroform-d)δ195.80,166.73(d,J=256.0Hz),165.04,164.00,163.79(d,J=31.9Hz),161.49,133.47(d,J=3.7Hz),132 .06,131.92(d,J=9.5Hz),129.94(d,J=8.2Hz),117.06,116.42,116.28,116.05,115.90,115.43,115.29,46.08,38.23,38.07,13.84. 19 FNMR(565MHz,Chloroform-d)δ-104.17,-104.38(d),-113.93.

[0038] Example 3

[0039] A method for synthesizing α-aryl ketone compounds from aryl allyl amides, the synthesis reaction equation is shown in (1-3):

[0040]

[0041] The synthesis method comprises the following steps:

[0042] The boron carbon nitrogen photocatalyst (10 mg), the reaction substrate N-(1-(4-(methylthio)phenyl-1-)phenylallyl)benzamide (35.9 mg, 0.1 mmol, 1 equiv), and the base K2HPO4 (26.1 mg, 0.15 mmol, 1.5 equiv) were added in sequence to a 10 mL Schlenk reaction tube equipped with a stirrer, followed by the addition of the fluorinated free radical precursor ethyl bromodifluoroacetate (32 uL, 0.25 mmoL, 0.25 equiv), the solvent DMF (1 mL, 0.1 M) and 10 uL H2O, and then the liquid was frozen with liquid nitrogen. After the solvent became solid, the reaction tube was evacuated with a double-row tube to replace it with a N2 atmosphere, and the evacuation was repeated three times, and then the reaction tube was thawed and sealed. The reaction tube was fixed in a glass container with condensed water reflux, the reaction temperature was maintained at 25-30°C, the speed of the stirrer used for the reaction was adjusted to 700 r / min, a 3W blue LED lamp (wavelength of about 450 nm) was used for irradiation at a distance of 0.5 cm, and the reaction was stirred for 20 h.

[0043] After the reaction, the reaction solution was extracted with ethyl acetate, washed three times with 30 ml of saturated brine, the organic phases were combined, dried over anhydrous Na2SO4, filtered, and the solvent was distilled under reduced pressure to obtain a crude product, which was finally purified by column chromatography with a mixed solvent of petroleum ether and ethyl acetate in a volume ratio of 20:1 to obtain ethyl 2,2-difluoro-4-(4-(methylthio)phenyl)-5-oxo-5-phenylpentanoate The yield of the product was 77% (291 mg). 1 H NMR(600MHz,Chloroform-d)δ7.95–7.84(m,2H),7.48(t,J=7.4Hz,1H),7.38(t,J=7.8Hz,2H),7.23–7.10(m,4H),4.94–4. 86(m,1H),4.21–4.11(m,1H),4.10–3.99(m,1H),3.32–3.17(m,1H),2.56–2.47(m,1H),2.40(s,3H),1.21(t,J=7.2Hz,3H). 13 C NMR(151MHz,Chloroform-d)δ197.27,164.07(t),138.37,135.80,134.39,133.38,129.33,128.90 ,128.80,128.74,128.29,127.76,127.09,125.01,115.37,63.06,46.40,37.99(t),15.58,13.82. 19F NMR(565MHz,Chloroform-d)δ-104.15,-104.18,-104.21,-104.24,-104.26,-104.29,-104.32.

[0044] Example 4

[0045] A method for synthesizing α-aryl ketone compounds from aryl allyl amides, the synthesis reaction equation is shown in (1-4):

[0046]

[0047] The synthesis method comprises the following steps:

[0048] The boron carbon nitrogen photocatalyst (10 mg), the reaction substrate N-(1-(4-fluorophenyl)-1-phenylallyl)benzamide (33.1 mg, 0.1 mmol, 1 equiv), and the base K2HPO4 (26.1 mg, 0.15 mmol, 1.5 equiv) were added in sequence to a 10 mL Schlenk reaction tube equipped with a stirrer, followed by the addition of the fluorinated free radical precursor ethyl bromodifluoroacetate (32 uL, 0.25 mmoL, 0.25 equiv), the solvent DMF (1 mL, 0.1 M) and 10 uL H2O, and then the liquid was frozen with liquid nitrogen. After the solvent became solid, the reaction tube was evacuated with a double-row tube to replace it with a N2 atmosphere, and the evacuation was repeated three times, and then the reaction tube was thawed and sealed. The reaction tube was fixed in a glass container with condensed water reflux, the reaction temperature was maintained at 25-30°C, the speed of the stirrer used for the reaction was adjusted to 700 r / min, a 3W blue LED lamp (wavelength of about 450 nm) was used for irradiation at a distance of 0.5 cm, and the reaction was stirred for 20 h.

[0049] After the reaction, the reaction solution was extracted with ethyl acetate, washed three times with 30 ml of saturated brine, the organic phases were combined, dried over anhydrous Na2SO4, filtered, and the solvent was distilled under reduced pressure to obtain a crude product. Finally, column chromatography was performed with a mixed solvent of petroleum ether and ethyl acetate with a volume ratio of 12:1 to obtain a colorless oily product ethyl 2,2-difluoro-4-(4-fluorophenyl)-5-oxo-5-phenylpentanoate at a mixing ratio of 1:2.45. and ethyl2,2-difluoro-5-(4-fluorophenyl)-5-oxo-4-phenylpentanoate The yield was 82% (287 mg). 1H NMR(600MHz,Chloroform-d)δ8.01–7.92(m,2H),7.39–7.13(m,5H),7.04(t,J=8.6Hz,2H),4.99–4.92(m,0.28H),4.90(dd ,J=8.0,4.9Hz,0.72H),4.21–4.08(m,1H),4.14–4.02(m,1H),3.37–3.15(m,1H),2.59–2.39(m,1H),1.22(t,J=7.2Hz,3H). 13 C NMR(151MHz,Chloroform-d)δ195.92,166.66,164.97,137.72,131.64,131.58,12 9.98,129.41,128.89,128.26,127.91,115.95(d),63.07,46.99,38.38(t),14.17. 19 FNMR (565MHz, Chloroform-d) δ -104.14–-104.51 (m), -114.11–-114.19 (m). Example 5

[0050] A method for synthesizing α-aryl ketone compounds from aryl allyl amides, the synthesis reaction equation is shown in (1-5):

[0051]

[0052] The synthesis method comprises the following steps:

[0053] The boron carbon nitrogen photocatalyst (10 mg), the reaction substrate N-(1-(3-chlorophenyl)-1-phenylallyl)benzamide (34.7 mg, 0.1 mmol, 1 equiv), and the base K2HPO4 (26.1 mg, 0.15 mmol, 1.5 equiv) were added in sequence to a 10 mL Schlenk reaction tube equipped with a stirrer, followed by the addition of the fluorinated free radical precursor ethyl bromodifluoroacetate (32 uL, 0.25 mmoL, 0.25 equiv), the solvent DMF (1 mL, 0.1 M) and 10 uL H2O, and then the liquid was frozen with liquid nitrogen. After the solvent became solid, the reaction tube was evacuated with a double-row tube to replace it with a N2 atmosphere, and the evacuation was repeated three times, and then the reaction tube was thawed and sealed. The reaction tube was fixed in a glass container with condensed water reflux, the reaction temperature was maintained at 25-30°C, the speed of the stirrer used for the reaction was adjusted to 700 r / min, a 3W blue LED lamp (wavelength of about 450 nm) was used for irradiation at a distance of 0.5 cm, and the reaction was stirred for 20 h.

[0054] After the reaction, the reaction solution was extracted with ethyl acetate, washed three times with 30 ml of saturated brine, the organic phases were combined, dried over anhydrous Na2SO4, filtered, and the solvent was distilled under reduced pressure to obtain a crude product. Finally, column chromatography was performed with a mixed solvent of petroleum ether and ethyl acetate in a volume ratio of 14:1 to obtain a colorless oily product ethyl 5-(3-chlorophenyl)-2,2-difluoro-5-oxo-4-phenylpentanoate in a mixing ratio of 3:7. and ethyl 4-(3-chlorophenyl)-2,2-difluoro-5-oxo-5-phenylpentanoate The yield was 78% (286 mg). 1 H NMR(600MHz,Chloroform-d)δ7.96–7.86(m,1.7H),7.80(d,J=10.5Hz,0.29H),7.51 (t,J=7.4Hz,0.74H),7.46–7.36(m,1.74H),7.34–7.24(m,2.31H),7.24–7.16(m,2. 41H),4.94(dd,J=8.0,5.0Hz,0.7H),4.88(dd,J=8.1,4.8Hz,0.29H),4.22–4.12(m, 1H),4.12–4.02(m,1H),3.32–3.15(m,1H),2.60–2.41(m,1H),1.23(t,J=7.2Hz,3H). 13 C NMR(151MHz,Chloroform-d)δ196.88,196.22,163.75(t,J=32.5Hz),139.79,135.57,135.07,133.64,133.27,130.59,130.04,129.4 8,128.89(d,J=9.3Hz),128.45–127.93(m),126.99,126.62,115.19,113.53,63.18,46.43,38.14(t,J=23.4Hz),13.85(d,J=2.7Hz). 19 F NMR (565MHz, Chloroform-d) δ-104.31 (dtd, J=43.6, 28.2, 27.0, 16.3Hz).

[0055] Example 6

[0056] A method for synthesizing α-aryl ketone compounds from aryl allyl amides, the synthesis reaction equation is shown in (1-6):

[0057]

[0058] The synthesis method comprises the following steps:

[0059] The boron carbon nitrogen photocatalyst (10 mg), the reaction substrate α, α-diphenylallylamide (31.3 mg, 0.1 mmol, 1 equiv), and the base K2HPO4 (26.1 mg, 0.15 mmol, 1.5 equiv) were added in sequence to a 10 mL Schlenk reaction tube equipped with a stirrer, followed by the addition of the fluorinated free radical precursor perfluoroiodobutane (43 uL, 0.25 mmoL, 0.25 equiv), the solvent DMF (1 mL, 0.1 M) and 10 uL H2O, and then the liquid was frozen with liquid nitrogen. After the solvent became solid, the reaction tube was evacuated with a double-row tube to replace it with a N2 atmosphere, and the evacuation was repeated three times, and then the reaction tube was thawed and sealed. The reaction tube was fixed in a glass container with condensed water reflux, the reaction temperature was maintained at 25-30°C, the speed of the stirrer used for the reaction was adjusted to 700 r / min, a 3W blue LED lamp (wavelength of about 450 nm) was used for irradiation at a distance of 0.5 cm, and the reaction was stirred for 20 h.

[0060] After the reaction, the reaction solution was extracted with ethyl acetate, washed three times with 30 ml of saturated brine, the organic phases were combined, dried over anhydrous Na2SO4, filtered, and the solvent was distilled under reduced pressure to obtain a crude product, which was finally purified by column chromatography with a mixed solvent of petroleum ether and ethyl acetate in a volume ratio of 30:1 to obtain 4,4,5,5,6,6,7,7,7-nonafluoro-1,2-diphenylheptan-1-one The yield of the product was 84% ​​(360 mg).

[0061] Example 7

[0062] A method for synthesizing α-aryl ketone compounds from aryl allyl amides, the synthesis reaction equation is shown in (1-7):

[0063]

[0064] The synthesis method comprises the following steps:

[0065] The boron carbon nitrogen photocatalyst (10 mg), the reaction substrate α, α-diphenylallylamide (31.3 mg, 0.1 mmol, 1 equiv), and the base K2HPO4 (26.1 mg, 0.15 mmol, 1.5 equiv) were added in sequence to a 10 mL Schlenk reaction tube equipped with a stirrer, followed by the addition of the fluorinated free radical precursor perfluoroiodohexane (54 uL, 0.25 mmoL, 0.25 equiv), the solvent DMF (1 mL, 0.1 M) and 10 uL H2O, and then the liquid was frozen with liquid nitrogen. After the solvent became solid, the reaction tube was evacuated with a double-row tube to replace it with a N2 atmosphere, and the evacuation was repeated three times, and then the reaction tube was thawed and sealed. The reaction tube was fixed in a glass container with condensed water reflux, the reaction temperature was maintained at 25-30°C, the speed of the stirrer used for the reaction was adjusted to 700 r / min, a 3W blue LED lamp (wavelength of about 450 nm) was used for irradiation at a distance of 0.5 cm, and the reaction was stirred for 20 h.

[0066] After the reaction, the reaction solution was extracted with ethyl acetate, washed three times with 30 ml of saturated brine, the organic phases were combined, dried over anhydrous Na2SO4, filtered, and the solvent was distilled off under reduced pressure to obtain a crude product, which was finally purified by column chromatography with a mixed solvent of petroleum ether and ethyl acetate in a volume ratio of 30:1 to obtain 4,4,5,5,6,6,7,7,8,8,9,9,9-tridecafluoro-1,2-diphenylnonan-1-one The yield was 76% (401 mg). 1 HNMR(600MHz,Chloroform-d)δ7.97(d,J=8.3Hz,2H),7.50(t,J=7.6Hz,1H),7.40(t,J=7.9Hz,2H),7.34–7 .28(m,4H),7.24(dd,J=6.1,3.3Hz,1H),5.03(dd,J=8.4,4.1Hz,1H),3.63–3.31(m,1H),2.64–2.32(m,1H). 13 C NMR (151MHz, Chloroform-d) δ196.77, 137.75, 135.71, 133.46, 129.50, 128.84 (d, J = 22.4Hz), 128.13, 127.95, 45.66, 34.50 (t, J = 20.8Hz). 19F NMR (565MHz, Chloroform-d) δ -80.71 (t, J = 10.7Hz), -111.64, -112.12, -112.89, -113.34, -121.70, -122.78, -123.39, -126.04.

[0067] ________________

[0068] [1] XU P, HU K, GU Z, et al. Visible light promoted carbodifluoroalkylation of allylic alcohols via concomitant 1,2-arylmigration[J]. Chemical Communications, 2015, 51(33):7222-7225.

[0069] [2] GE D,WANG X,CHU

[0070] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention should fall within the scope of the present invention.

Claims

1. A method for synthesizing α-aryl ketone compounds from aryl allyl amides, characterized in that: The following steps are involved: Adding a reaction substrate, a photocatalyst, a fluorine-containing free radical precursor and a base into a reaction container, then adding a solvent under a nitrogen atmosphere, stirring and reacting at room temperature for 20 to 24 hours under light conditions, and then separating and purifying to obtain an α-aryl ketone compound; The general structural formula of the reaction substrate is shown in formula (I) or formula (II): Among them, R1 is hydrogen, substituted methyl, ethyl, halogen, trifluoromethyl, methoxy, thiomethyl, trifluoromethoxy, tert-butyl; R2 is hydrogen, alkyl or halogen; R3 is hydrogen or alkoxy; R4 is hydrogen, alkyl, halogen or alkoxy; R5 is hydrogen or alkyl; R6 is hydrogen, cycloalkyl, thiophene or benzodioxolane.

2. The method for synthesizing α-aryl ketone compounds from aryl allyl amides according to claim 1, characterized in that: The molar ratio of the photocatalyst, base, fluorine-containing free radical precursor and reaction substrate used is (1-5):(1-3):(2-4):(1-2).

3. The method for synthesizing α-aryl ketone compounds from aryl allyl amides according to claim 1 or 2, characterized in that: The aryl allyl amide includes any one of the diaryl allyl amides.

4. The method for synthesizing α-aryl ketone compounds from aryl allyl amides according to claim 1 or 2, characterized in that: The photocatalyst is a boron-carbon-nitrogen material prepared by a high-temperature molten salt method.

5. The method for synthesizing α-aryl ketone compounds from aryl allyl amides according to claim 1 or 2, characterized in that: The fluorine-containing free radical precursor is one of ethyl bromodifluoroacetate, perfluoro iodide and perfluoro bromide.

6. The method for synthesizing α-aryl ketone compounds from aryl allyl amides according to claim 1, characterized in that: The base is hydrogen phosphate, phosphate, carbonate, bicarbonate or an organic base.

7. The method for synthesizing α-aryl ketone compounds from aryl allyl amides according to claim 1, characterized in that: The solvent is one of MeCN, DMF, DMA, THF and DMSO.

8. The method for synthesizing α-aryl ketone compounds from aryl allyl amides according to claim 1, characterized in that: The nitrogen pressure in the reaction container is normal pressure; the distance between the light source and the reaction container is 0.1-3 cm, the wavelength of the light is 390-460 nm, and the power of the light source is 3-50 W.

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