A method for the green catalytic synthesis of γ-ketophosphine oxides from asymmetric alkylaluminum compounds

Abstract

This invention discloses a method for the green catalytic synthesis of γ-ketophosphine oxides from asymmetric alkylaluminum compounds under mild conditions. Using phosphine oxides as raw materials and an asymmetric alkylaluminum compound as a catalyst, the reaction proceeds with α,β-unsaturated ketones in the range of 60°C to 100°C and in the presence of an organic solvent to generate γ-ketophosphine oxides. This method features mild reaction conditions, high product yield, broad substrate scope, and the absence of added acids, bases, and heavy metals, thus meeting the requirements of green chemistry and atom-economical reactions.

Description

Technical Field

[0001] This invention relates to a method for the green catalytic synthesis of γ-ketophosphine oxides from asymmetric alkylaluminum compounds, specifically belonging to the fields of green catalysis and pharmaceutical synthesis intermediates. Background Technology

[0002] Organophosphorus compounds have wide applications in organic synthesis, medicinal chemistry, agricultural chemistry, and materials science. Among them, γ-ketophosphorus oxides have attracted widespread attention in organic and medicinal chemistry over the past few decades due to their unique structural features and diverse and interesting biological properties. Traditional synthetic methods for γ-ketophosphorus oxides mainly rely on the Phospha-Michael reaction, i.e., the phosphonylation reaction of α,β-unsaturated carbonyl compounds with nucleophilic phosphine reagents. This reaction often relies on strong acids, strong bases, and noble metals for catalysis, and has a limited substrate range. These catalysts are relatively expensive and environmentally harmful, and cannot fully meet the requirements of industrial production and sustainable development (G. Strapaveccia, L. Bianchi, S. Ziarelli, et al. PS-BEMP as a Basic Catalyst for the Phospha-Michael Addition to Electron-poor Alkenes. Org. Biomol. Chem. 2016, 14, 3521.).

[0003] Phospha-MichaelReaction

[0004]

[0005] Aluminum is abundant, inexpensive, and has low biotoxicity. With the development of green chemistry, aluminum and magnesium, among other main group metal catalysts, have become a research hotspot. To this end, we have invented a catalyst with an asymmetric alkylaluminum structure. This catalyst can greenly and efficiently catalyze the Phospha-Michael reaction to obtain γ-ketophosphine oxides, exhibiting high activity, no pollution, and strong substrate tolerance. Summary of the Invention

[0006] The purpose of this invention is to provide a green catalytic method for the synthesis of γ-ketophosphine oxides;

[0007] The purpose of this invention is to provide a green, high-performance catalyst for the Phospha-Michael reaction;

[0008] The purpose of this invention is to provide a method for generating γ-ketophosphine oxides by reacting phosphine oxides with α,β-unsaturated ketones under the catalysis of asymmetric alkylaluminum compounds.

[0009] The method of the present invention is further described as follows: in the range of 60°C to 100°C and in the presence of an organic solvent, using phosphine oxide as a raw material and an asymmetric alkylaluminum compound as a catalyst, reacting with α,β-unsaturated ketones to generate γ-ketophosphine oxides.

[0010] The molar ratio of the phosphine oxychloride compound, α,β-unsaturated ketone, and asymmetric alkylaluminum compound is 1–1.2:1:0.01–0.01.

[0011] The asymmetric alkylaluminum compound used in this invention has the following structural formula:

[0012]

[0013] R2 is selected from 2,6-diisopropylphenyl, 2,6-diethylphenyl, and 2,4,6-trimethylphenyl, and R3 is selected from methyl, ethyl, and isobutyl.

[0014] The phosphine oxychloride compound used in this invention has the following structural formula:

[0015]

[0016] Among them, R1 is selected from methyl, methoxy, ethoxy, R x Substituted phenyl or naphthyl groups; X is selected from halogens, methoxy groups, methyl groups, and ethyl groups;

[0017] The α,β-unsaturated ketone used in this invention has the following structural formula:

[0018]

[0019] R4 is selected from phenyl, R x Substituted phenyl, naphthyl, cyclohexyl, n-propyl, styryl, phenylethynyl, 2-pyridyl, 2-thiophene; X is selected from halogen, methyl, hydroxyl, nitro, trifluoromethyl, methoxy, cyano, dimethylamino; R5 is selected from phenyl, R x Substituted phenyl, methyl, n-butyl, tert-butyl;

[0020] The γ-ketophosphine oxide of the present invention has the following structural formula:

[0021]

[0022] Where R x The substitution position is opposite, adjacent, or metaposition, and the number of substitutions is 1 or 2;

[0023] The asymmetric alkylaluminum catalyst used in this invention has the structure described above. The aryl group R2 attached to the N atoms at both ends is recommended to be 2,4,6-trimethylphenyl, and the alkyl group R3 attached to the aluminum atom is recommended to be methyl or ethyl, with methyl being a further recommended choice.

[0024] The structure of the α,β-unsaturated ketone used in this invention is as described above, and the group R4 attached to the β-carbon atom is recommended to be phenyl or R x Substituted phenyl, naphthyl, 2-pyridyl, 2-thiophene; the mentioned R x The substituted phenyl group is recommended to be halogenated, methyl, hydroxyl, nitro, trifluoromethyl, methoxy, cyano, or dimethylamino, with further recommendations being alkyl, hydroxyl, nitro, trifluoromethyl, or methoxy; the group R5 attached to the carbon atom of the ketone is recommended to be phenyl or R x Substituted phenyl, methyl, n-butyl, tert-butyl;

[0025] The structure of the phosphine oxide compound used in this invention is as described above, wherein the group R1 attached to the phosphorus atom is preferably methyl, methoxy, ethoxy, phenyl, or R... x Substituted phenyl or naphthyl groups are further recommended as phenyl or R groups. x Substituted phenyl; X is selected from halogen, methoxy, methyl, ethyl;

[0026] The percentage of the asymmetric alkylaluminum catalyst used in the method of the present invention is 1% to 10%, the recommended percentage is 1% to 5%, and the further recommended percentage is 5%.

[0027] The alkylaluminum catalyst used in the method of this invention can be stored in dry air for more than three days; and stored in a dry nitrogen atmosphere for several months.

[0028] The reaction temperature range in the method of this invention is 60℃~100℃, and the recommended reaction temperature is 80℃;

[0029] The organic solvent used in the method of this invention can be a polar solvent or a non-polar solvent, such as n-hexane, toluene, tetrahydrofuran, chloroform, etc. Toluene is recommended as the reaction solvent.

[0030] The reaction concentration in the method of this invention is 0.4 mmol / mL to 1 mmol / mL, and the recommended reaction concentration is 0.4 mmol / mL;

[0031] The reaction time in the method of this invention is 2h to 10h, and the recommended reaction time is 3h;

[0032] The product obtained by the method of the present invention can be separated by vacuum filtration, recrystallization, thin-layer chromatography, and column chromatography.

[0033] If separation is performed by recrystallization, a mixed solvent of polar and nonpolar solvents is recommended, with ethyl acetate-petroleum ether being a preferred solvent. When separation is performed by thin-layer chromatography or column chromatography, a mixed solvent of dichloromethane and methanol is recommended, with a dichloromethane to methanol ratio of 16:1 being further recommended.

[0034] This invention provides a method for obtaining various γ-ketophosphine oxides by reacting phosphine oxy compounds with α,β-unsaturated ketones under the catalysis of asymmetric alkylaluminum compounds, characterized by low pollution, high yield, and high substrate tolerance. Compared with existing methods, this invention has the following advantages:

[0035] (1) This invention is the first to discover that alkyl aluminum compounds supported by β-diimine ligands can efficiently catalyze the Phospha-Michael reaction under mild reaction conditions, without added acids, bases or heavy metals, which meets the requirements of green chemistry and atom economy reaction.

[0036] (2) The catalyst of the present invention uses aluminum, a main group metal, which is abundant, inexpensive and non-toxic, and not very sensitive to air, and has the prospect of large-scale industrial application.

[0037] (3) Compared with other complex transition metal complex catalysts, the asymmetric alkylaluminum catalyst in this invention has a simple preparation method. It can be obtained by dissolving the ligand and reacting it with the alkylaluminum reagent in one step. The solvent can be used directly after being dried without further separation.

[0038] (4) This invention overcomes the difficulty of the narrow substrate range of the Phospha-Michael reaction catalyzed by traditional catalysts. The Phospha-Michael reaction catalyzed by the asymmetric alkyl aluminum catalyst mentioned in this invention can provide a yield of up to 99% with a catalytic loading of 1 mol% for 6 h. It also has the characteristics of a wide substrate range and easy separation after reaction. Detailed Implementation

[0039] The present invention will be described in detail below with reference to embodiments. However, it should be understood that the embodiments are only used to illustrate the present invention and do not constitute any limitation on the scope of protection of the present invention. All reasonable modifications and combinations included within the scope of the inventive spirit of the present invention fall within the scope of protection of the present invention.

[0040] The asymmetric β-diimine ligands used in the following examples have the following structures:

[0041]

[0042] The asymmetric alkylaluminum catalyst used in the following examples has the following structure:

[0043]

[0044] Example 1

[0045] Synthesis of Catalyst 5

[0046] (1) Under an inert atmosphere, 1 mmol of asymmetric β-diimine ligand L3 and 1 mL of trimethylaluminum n-hexane solution (1 mmol / mL) were reacted in 10 mL of n-hexane at 0 °C, and the reaction mixture was heated to 40 °C to 50 °C and stirred continuously for 11 to 13 hours to obtain an aluminum methyl compound solution with asymmetric β-diimine ligand L3 as a stable component.

[0047] (2) The solution of the aluminum methyl compound stabilized by the asymmetric β-diimine ligand L3 was concentrated to 5 mL and crystallized at -15℃ to 5℃ for 24 hours to obtain a yellow crystalline compound.

[0048]

[0049] 1 H NMR (400MHz, CDCl3) δ6.80(d,J=4.8Hz,4H),2.37(t,J=6.3Hz,2H),2.19(d,J=2.2Hz,6H),2.06(d,J= 2.6Hz,12H),1.92(q,J=6.6Hz,2H),1.71(s,3H),1.65-1.53(m,2H),1.50-1.41(m,2H),-1.23(s,6H). 13 C NMR(101MHz, CDCl3)δ168.39(s),166.52(s),140.04(s),139.78(s),133.68(s),133.44(s),132.41(d,J=11.3Hz),128.1 3(d,J=1.4Hz),99.75(s),30.08(s),27.72(s),22.34(s),21.47(s),19.79(d,J=1.0Hz),18.00(s),17.76(s),-9.98(s).

[0050] Example 2

[0051]

[0052] Under nitrogen protection, 1 mmol (0.1462 g) of 4-phenyl-3-buten-2-one and 1.2 mmol (0.2424 g) of diphenylphosphine oxide were added to a 10 mL Schlenk flask, followed by 5 mmol (0.0215 g) of the obtained catalyst crystals, and finally 2.5 mL of anhydrous toluene. The resulting solution was reacted in an oil bath at 80 °C for 3 hours. After cooling, the solvent was removed to obtain a yellow crude product. The crude product was separated by column chromatography (dichloromethane:methanol = 30:1) to give 331 mg (95% yield, 0.95 mmol) of a white powder.

[0053] 1 H NMR (400MHz, CDCl3) δ7.93 (ddd, J = 10.7, 7.9, 1.6Hz, 2H), 7.60-7.48 (m, 3H), 7.47-7.39 (m, 2H), 7.36-7.27 (m, 3H), 7.25-7.19 (m, 2H), 7.1 9-7.08(m,3H),4.21(ddd,J=10.2,7.3,2.9Hz,1H),3.32(ddd,J=17.8,10.1,5.3Hz,1H),2.94(ddd,J=17.9,11.2,2.9Hz,1H),1.95(s,3H). 13 C NMR (101MHz, CDCl3) δ205.37 (d, J = 12.7Hz), 135.86 (d, J = 5.6Hz), 132.18-131.40 (m), 131.33 (d, J = 8.5Hz), 131.15-130.80 (m), 129.74 (d, J =5.6Hz), 128.89 (d, J = 11.3Hz), 128.35 (d, J = 1.9Hz), 128.07 (d, J = 11.8Hz), 127.13 (d, J = 2.5Hz), 43.58 (s), 41.12 (d, J = 68.7Hz), 30.63 (s). 31 P NMR (162MHz, CDCl3) δ33.61 (s).

[0054] Example 3

[0055]

[0056] Under nitrogen protection, 1 mmol (0.1806 g) of 4-(4-chlorophenyl)-3-buten-2-one and 1.2 mmol (0.2424 g) of diphenylphosphine oxide were added to a 10 mL Schlenk flask, followed by 5 mmol (0.0215 g) of the obtained catalyst crystals, and finally 2.5 mL of anhydrous toluene. The resulting solution was reacted in an oil bath at 80 °C for 3 hours. After cooling, the solvent was removed to obtain a yellow crude product. The crude product was separated by column chromatography (dichloromethane:methanol = 30:1) to give 376 mg (97% yield, 0.97 mmol) of a white powder.

[0057] 1 H NMR (400MHz, CDCl3) δ7.96-7.87(m,2H),7.60-7.50(m,3H),7.49-7.42(m,2H),7.36(td,J=7.4,1.2Hz,1H),7.30-7.26(m,2H),7.24(d,J=1.8Hz,2H ),7.13(d,J=8.4Hz,2H),4.19(ddd,J=10.1,7.2,2.8Hz,1H),3.26(ddd,J= 18.0,10.2,5.1Hz,1H),2.91(ddd,J=18.1,10.9,2.8Hz,1H),1.96(s,3H). 13 C NMR (101MHz, CDCl3) δ205.07 (d, J = 12.7Hz), 134.58 (d, J = 5.5Hz), 133.08 (d, J = 2.9Hz), 132.15 (d, J = 2.7Hz), 131.69 (t, J = 6.5Hz), 131.23 (d, J = 8 .6Hz),130.88(td,J=12.0,5.4Hz),128.98(d,J=11.3Hz),128.53(d,J=1 .8Hz), 128.27(d,J=11.8Hz), 43.60(s), 40.43(d,J=68.6Hz), 30.58(s). 31 P NMR(162MHz, CDCl3)δ33.14(s).

[0058] Example 4

[0059]

[0060] Under nitrogen protection, 1 mmol (0.1642 g) of 4-(4-fluorophenyl)-3-buten-2-one and 1.2 mmol (0.2424 g) of diphenylphosphine oxide were added to a 10 mL Schlenk flask, followed by 5 mmol (0.0215 g) of the obtained catalyst crystals, and finally 2.5 mL of anhydrous toluene. The resulting solution was reacted in an oil bath at 80 °C for 3 hours. After cooling, the solvent was removed to obtain a yellow crude product. The crude product was separated by column chromatography (dichloromethane:methanol = 30:1) to give 337 mg (92% yield, 0.92 mmol) of a white powder.

[0061] 1 H NMR (400MHz, CDCl3) δ7.90-7.81(m,2H),7.53-7.42(m,3H),7.42-7.33(m,2H),7.31-7.24(m,1H),7.24-7.20(m,2H),7.19-7.15(m,2H),6. 82-6.75(m,2H),4.13(ddd,J=10.1,7.1,2.8Hz,1H),3.20(ddd,J=18.0,10.3,5.1Hz,1H),2.84(ddd,J=18.1,10.9,2.8Hz,1H),1.89(s,3H). 13 C NMR (101MHz, CDCl3) δ205.19 (d, J = 12.8Hz), 161.92 (dd, J = 246.1, 2.6Hz), 132.21-131.85 (m), 131.80-131.44 (m), 131.30 (d, J = 2.1Hz), 131.21 (dd, J = 5.3,2.7Hz),130.97-130.72(m),128.95(d,J=11.3Hz),128.19(d,J=11.8H z), 115.28 (dd, J = 21.4, 1.8Hz), 43.69 (s), 40.24 (d, J = 69.1Hz), 30.59 (s). 31 P NMR(162MHz, CDCl3)δ33.38(s).

[0062] Example 5

[0063]

[0064] Under nitrogen protection, 1 mmol (0.2251 g) of 4-(4-bromophenyl)-3-buten-2-one and 1.2 mmol (0.2424 g) of diphenylphosphine oxide were added to a 10 mL Schlenk flask, followed by 5 mmol (0.0215 g) of the obtained catalyst crystals, and finally 2.5 mL of anhydrous toluene. The resulting solution was reacted in an oil bath at 80 °C for 3 hours. After cooling, the solvent was removed to obtain a yellow crude product. The crude product was separated by column chromatography (dichloromethane:methanol = 30:1) to give 375 mg (88% yield, 0.88 mmol) of a white powder.

[0065] 1 H NMR (400MHz, CDCl3) δ7.88-7.80(m,2H),7.52-7.35(m,5H),7.32-7.26(m,1H),7.21(dd,J=8.8,2.1Hz,3H),7.18(d,J=3.1Hz,1H),7.12(dd,J =8.5,1.8Hz,2H),4.11(ddd,J=10.1,7.2,2.8Hz,1H),3.19(ddd,J=18.1,10.2,5.1Hz,1H),2.84(ddd,J=18.1,11.0,2.8Hz,1H),1.89(s,3H). 13 C NMR (101MHz, CDCl3) δ205.02 (d, J = 12.7Hz), 135.14 (d, J = 5.5Hz), 132.15 (d, J = 2.7Hz), 131.80-131.60 (m), 131.47 (d, J = 1.8Hz), 131.29 (dd,J=15.3,7.1Hz),130.87(d,J=8.9Hz),128.63(dd,J=70.0,11.6Hz),121.25(d,J=3.1Hz),43.55(s),40.48(d,J=68.4Hz),30.56(s). 31 P NMR (162MHz, CDCl3) δ32.96 (s).

[0066] Example 6

[0067]

[0068] Under nitrogen protection, 1 mmol (0.1762 g) of 4-(4-methoxyphenyl)-3-buten-2-one and 1.2 mmol (0.2424 g) of diphenylphosphine oxide were added to a 10 mL Schlenk flask, followed by 5 mmol (0.0215 g) of the obtained catalyst crystals, and finally 2.5 mL of anhydrous toluene. The resulting solution was reacted in an oil bath at 80 °C for 3 hours. After cooling, the solvent was removed to obtain a yellow crude product. The crude product was separated by column chromatography (dichloromethane:methanol = 30:1) to give 359 mg (95% yield, 0.95 mmol) of a white powder.

[0069] 1 H NMR (400MHz, CDCl3) δ7.89-7.79(m,2H),7.51-7.34(m,5H),7.30-7.23(m,1H),7.19-7.11(m,4H),6.63(d,J=8.6Hz,2H),4 .09(ddd,J=10.2,7.4,2.8Hz,1H),3.20(ddd,J=17.6,10.3,5.3Hz,1H),2.82(ddd,J=17.8,10.8,2.8Hz,1H),1.87(s,3H). 13 C NMR (101MHz, CDCl3) δ204.51 (d, J = 13.0Hz), 157.60 (d, J = 2.3Hz), 131.01 (dd, J = 19.1, 5.1Hz), 130.42-130.27 (m), 130.18 (d, J = 7.3Hz), 129.84 (d d,J=26.6,7.2Hz),127.45(dd,J=76.1,11.5Hz),126.64(d,J=5.6Hz),11 2.78(d,J=1.7Hz),54.10(s),42.67(s),39.19(d,J=69.6Hz),29.66(s). 31 P NMR (162MHz, CDCl3) δ33.57 (s).

[0070] Example 7

[0071]

[0072] Under nitrogen protection, 1 mmol (0.1712 g) of 4-(4-cyanophenyl)-3-buten-2-one and 1.2 mmol (0.2424 g) of diphenylphosphine oxide were added to a 10 mL Schlenk flask, followed by 5 mmol (0.0215 g) of the obtained catalyst crystals, and finally 2.5 mL of anhydrous toluene. The resulting solution was reacted in an oil bath at 80 °C for 3 hours. After cooling, the solvent was removed to obtain a yellow crude product. The crude product was separated by column chromatography (dichloromethane:methanol = 30:1) to give 358 mg (96% yield, 0.96 mmol) of a white powder.

[0073] 1 H NMR (400MHz, CDCl3) δ7.90-7.81(m,2H),7.55-7.44(m,3H),7.41-7.34(m,6H),7.35-7.26(m,1H),7.19(ddd,J=8.1,3.5,2.0Hz ,2H),4.20(ddd,J=9.8,7.0,2.4Hz,1H),3.24(ddd,J=18.3,10.2,5.0Hz,1H),2.90(ddd,J=18.4,10.9,2.5Hz,1H),1.90(s,3H). 13 CNMR (101MHz, CDCl3) δ204.58 (d, J = 12.4Hz), 141.93 (d, J = 5.5Hz), 132.13 (dd, J = 52.1, 2.7Hz), 131.99 (d, J = 1.8Hz), 130.94 (dd, J = 46.1, 8.8Hz), 13 0.78(d,J=121.6Hz),130.43(t,J=4.9Hz),128.74(dd,J=72.1,11.7Hz),1 18.65(s), 110.96(d,J=2.5Hz), 43.36(s), 41.33(d,J=66.9Hz), 30.36(s). 31 P NMR (162MHz, CDCl3) δ32.73 (s).

[0074] Example 8

[0075]

[0076] Under nitrogen protection, 1 mmol (0.1893 g) of 4-(4-dimethylaminophenyl)-3-buten-2-one and 1.2 mmol (0.2424 g) of diphenylphosphine oxide were added to a 10 mL Schlenk flask, followed by 5 mmol (0.0215 g) of the obtained catalyst crystals, and finally 2.5 mL of anhydrous toluene. The resulting solution was reacted in an oil bath at 80 °C for 3 hours. After cooling, the solvent was removed to obtain a yellow crude product. The crude product was separated by column chromatography (dichloromethane:methanol = 30:1) to give 301 mg (77% yield, 0.77 mmol) of a pale yellow powder.

[0077] 1 H NMR (400MHz, CDCl3) δ7.87-7.79(m,2H),7.50-7.36(m,5H),7.26(t,J=7.3Hz,1H),7.19-7.13(m,3H),7.06(dd,J=8.6,1.6Hz,2H),6 .46(d,J=8.7Hz,2H),4.06(ddd,J=10.4,7.7,2.9Hz,1H),3.23-3.13(m,1H),2.86-2.79(m,1H),2.79(d,J=5.3Hz,6H),1.86(s,3H). 13 C NMR (101MHz, CDCl3) δ205.83 (d, J = 13.1Hz), 149.59 (d, J = 1.9Hz), 131.79 (d, J = 2.7Hz), 131.53-131.23 (m), 130.76 (dd, J = 79.8, 7.2Hz), 128.40 (d d,J=73.8,11.4Hz),127.69(dd,J=951.7,4.6Hz),122.96(d,J=5.8Hz),1 12.48(d,J=1.6Hz), 43.68(s), 40.47(s), 40.16(d,J=70.0Hz), 30.72(s). 31 P NMR (162MHz, CDCl3) δ33.64 (s).

[0078] Example 9

[0079]

[0080] Under nitrogen protection, 1 mmol (0.1602 g) of 4-(2-methylphenyl)-3-buten-2-one and 1.2 mmol (0.2424 g) of diphenylphosphine oxide were added to a 10 mL Schlenk flask, followed by 5 mmol (0.0215 g) of the obtained catalyst crystals, and finally 2.5 mL of anhydrous toluene. The resulting solution was reacted in an oil bath at 80 °C for 3 hours. After cooling, the solvent was removed to obtain a yellow crude product. The crude product was separated by column chromatography (dichloromethane:methanol = 30:1) to give 355 mg (98% yield, 0.98 mmol) of a white powder.

[0081] 1 H NMR (400MHz, CDCl3) δ7.92-7.82(m,2H),7.61(d,J=7.5Hz,1H),7.57-7.45(m ,3H),7.24(td,J=7.3,1.3Hz,1H),7.18-7.04(m,5H),7.04-6.95(m,1H),6.82 (d,J=7.5Hz,1H),4.35(ddd,J=10.1,7.6,2.7Hz,1H),3.30(ddd,J=17.9,10. 1,5.1Hz,1H),2.88(ddd,J=18.0,11.1,2.6Hz,1H),1.92(s,3H),1.87(s,3H). 13 C NMR (101MHz, CDCl3) δ205.53 (d, J = 13.1Hz), 135.80 (dd, J = 300.1, 6.0Hz), 131. 86(dd,J=67.9,2.7Hz),131.81(d,J=100.0Hz),131.30(dd,J=73.9,8.8Hz),13 1.08(s),130.15(s),130.12(s),128.79(s),128.39(dd,J=111.8,11.4Hz),12 6.68(dd,J=87.7,2.5Hz),44.41(s),36.14(d,J=68.3Hz),30.54(s),19.61(s). 31 P NMR(162MHz, CDCl3)δ34.13(s).

[0082] Example 10

[0083]

[0084] Under nitrogen protection, 1 mmol (0.1602 g) of 4-(3-methylphenyl)-3-buten-2-one and 1.2 mmol (0.2424 g) of diphenylphosphine oxide were added to a 10 mL Schlenk flask, followed by 5 mmol (0.0215 g) of the obtained catalyst crystals, and finally 2.5 mL of anhydrous toluene. The resulting solution was reacted in an oil bath at 80 °C for 3 hours. After cooling, the solvent was removed to obtain a yellow crude product. The crude product was separated by column chromatography (dichloromethane:methanol = 30:1) to give 351 mg (97% yield, 0.97 mmol) of a white powder.

[0085] 1 H NMR (400MHz, CDCl3) δ7.85 (ddd, J=10.6, 7.8, 1.5Hz, 2H), 7.51-7.40 (m, 3H), 7.40-7 .32(m,2H),7.26(td,J=7.4,1.3Hz,1H),7.16(td,J=7.5,3.0Hz,2H),6.98(p,J=7.6 Hz, 3H), 6.86 (d, J = 7.4Hz, 1H), 4.11 (ddd, J = 10.3, 7.6, 2.9Hz, 1H), 3.23 (ddd, J = 17. 8,10.1,5.5Hz,1H),2.87(ddd,J=17.9,11.4,2.9Hz,1H),2.13(s,3H),1.88(s,3H). 13 CNMR(101MHz,CDCl3)δ204.37(d,J=12.7Hz),136.82(d,J=1.9Hz),134.64(d,J=5.5 Hz), 131.00 (d, J = 4.1Hz), 130.93 (d, J = 2.7Hz), 130.35 (d, J = 3.1Hz), 130.18 (d, J = 20 .3Hz),130.05-129.96(m),127.59(dd,J=374.4,5.7Hz),127.38(dd,J=85.8,11.5Hz ),127.00(dd,J=28.1,2.2Hz),42.46(s),40.03(d,J=68.6Hz),29.58(s),20.27(s). 31 P NMR (162MHz, CDCl3) δ33.53 (s).

[0086] Example 11

[0087]

[0088] Under nitrogen protection, 1 mmol (0.1602 g) of 4-(4-methylphenyl)-3-buten-2-one and 1.2 mmol (0.2424 g) of diphenylphosphine oxide were added to a 10 mL Schlenk flask, followed by 5 mmol (0.0215 g) of the obtained catalyst crystals, and finally 2.5 mL of anhydrous toluene. The resulting solution was reacted in an oil bath at 80 °C for 3 hours. After cooling, the solvent was removed to obtain a yellow crude product. The crude product was separated by column chromatography (dichloromethane:methanol = 30:1) to give 329 mg (91% yield, 0.91 mmol) of a white powder.

[0089] 1 H NMR (400MHz, CDCl3) δ7.88-7.80(m,2H),7.52-7.34(m,5H),7.26(t,J=7.0Hz,1H),7.16(dd,J=7.4,2.7Hz,2H),7.10(d,J=6.7Hz,2H),6.9 0(t,J=9.7Hz,2H),4.12(ddd,J=10.1,7.6,2.7Hz,1H),3.27-3.15(m,1H),2.84(ddd,J=17.8,11.1,2.7Hz,1H),2.15(s,3H),1.86(s,3H). 13 C NMR (101MHz, CDCl3) δ205.43 (d, J = 12.9 Hz), 134.41 ( dd, J = 460.6, 2.3 Hz), 132.63 ( d, J = 5.6 Hz), 131.64 ( dd, J = 55.1, 2.7 Hz), 131.16 ( dd, J = 25.8, 8.7 Hz ),131.15(d,J=8.0Hz),129.55(d,J=5.7Hz),129.06(d,J=1.8Hz),128.44( dd,J=78.0,11.5Hz),43.63(s),40.65(d,J=69.1Hz),30.65(s),21.03(s). 31 P NMR (162MHz, CDCl3) δ33.39 (s).

[0090] Example 12

[0091]

[0092] Under nitrogen protection, 1 mmol (0.1522 g) of 4-cyclohexyl-3-buten-2-one and 1.2 mmol (0.2424 g) of diphenylphosphine oxide were added to a 10 mL Schlenk flask, followed by 5 mmol (0.0215 g) of the obtained catalyst crystals, and finally 2.5 mL of anhydrous toluene. The resulting solution was reacted in an oil bath at 80 °C for 3 hours. After cooling, the solvent was removed to obtain a yellow crude product. The crude product was separated by column chromatography (dichloromethane:methanol = 30:1) to give 216 mg (61% yield, 0.61 mmol) of a white powder.

[0093] 1 H NMR (400MHz, CDCl3) δ7.86-7.62(m,4H),7.45-7.27(m,6H),3.24-2.96(m,1H),2.91-2 .49(m,2H),2.02(d,J=9.8Hz,1H),1.85(s,3H),1.72-1.37(m,5H),1.10-0.78(m,5H). 13 C NMR (101MHz, CDCl3) δ205.17 (d, J = 8.3Hz), 131.86 (dd, J = 95.0, 9.8Hz), 130.49 (t, J = 2.7Hz), 129.92 (dd, J = 18.3, 8.6Hz), 127.58 (t, J = 11.1H z), 36.90 (s), 36.73 (d, J = 1.5Hz), 35.60 (d, J = 71.8Hz), 31.93 (d, J = 12.7Hz), 28.84 (s), 28.40 (d, J = 2.6Hz), 25.63 (s), 25.13 (d, J = 29.4Hz). 31 P NMR (162MHz, CDCl3) δ36.60 (s).

[0094] Example 13

[0095]

[0096] Under nitrogen protection, 1 mmol (0.1522 g) of 4-(2-thienyl)-3-buten-2-one and 1.2 mmol (0.2424 g) of diphenylphosphine oxide were added to a 10 mL Schlenk flask, followed by 5 mmol (0.0215 g) of the obtained catalyst crystals, and finally 2.5 mL of anhydrous toluene. The resulting solution was reacted in an oil bath at 80 °C for 3 hours. After cooling, the solvent was removed to obtain a yellow crude product. The crude product was separated by column chromatography (dichloromethane:methanol = 30:1) to give 287 mg (82% yield, 0.82 mmol) of white powder.

[0097] 1 H NMR (400MHz, CDCl3) δ7.89-7.80(m,2H),7.55-7.40(m,5H),7.36-7.28(m,1H),7.27-7.20(m,2H),6.99(d,J=5.1Hz,1H),6.85(t,J=2.7Hz,1H),6.7 4(dd,J=5.1,3.6Hz,1H),4.51(ddd,J=10.6,8.1,2.9Hz,1H),3.20(ddd,J= 17.8,10.3,5.0Hz,1H),2.86(ddd,J=17.8,10.3,2.9Hz,1H),1.93(s,3H). 13 C NMR (101MHz, CDCl3) δ204.97 (d, J = 12.2Hz), 137.53 (d, J = 6.3Hz), 131.92 (dd, J = 45.7, 2.7Hz), 131.52 (d, J = 3.5Hz), 131.21 (dd, J = 21.5, 8.8Hz), 130.54(d,J=9.5Hz), 128.56(dd,J=72.7,11.6Hz), 127.32(d,J=6.5Hz), 125.84(dd,J=185.1,2.7Hz), 44.38(s), 36.62(d,J=70.5Hz), 30.60(s). 31 P NMR (162MHz, CDCl3) δ32.52 (s).

[0098] Example 14

[0099]

[0100] Under nitrogen protection, 1 mmol (0.1722 g) of 4-(styryl)-3-buten-2-one and 1.2 mmol (0.2424 g) of diphenylphosphine oxide were added to a 10 mL Schlenk flask, followed by 5 mmol (0.0215 g) of the obtained catalyst crystals, and finally 2.5 mL of anhydrous toluene. The resulting solution was reacted in an oil bath at 80 °C for 3 hours. After cooling, the solvent was removed to obtain a yellow crude product. The crude product was separated by column chromatography (dichloromethane:methanol = 30:1) to give 243 mg (65% yield, 0.65 mmol) of a white powder.

[0101] 1H NMR (400MHz, CDCl3) δ7.82-7.65(m,4H),7.50-7.30(m,6H),7.18-7.07(m,5H),6.30(dd,J=15.9,4.2Hz,1H),5.98(ddd,J=15.8,9 .2, 6.4Hz, 1H), 3.86 (qd, J=9.4, 2.9Hz, 1H), 2.91 (ddd, J=17.6, 9.8, 5.4Hz, 1H), 2.78 (ddd, J=17.7, 11.3, 2.9Hz, 1H), 2.00 (s, 3H). 13 C NMR (101MHz, CDCl3) δ204.22 (d, J = 12.7Hz), 135.55 (d, J = 2.8Hz), 134.21 (d, J = 11.6Hz), 131.14-130.72 (m), 130.27 (dd, J = 17.8, 8.7Hz), 129.90 (d, J = 21.8Hz),127.82(d,J=11.4Hz),127.43(t,J=5.8Hz),126.65(s),125.27(d ,J=1.5Hz),122.31(d,J=7.4Hz),40.72(s),37.88(d,J=70.2Hz),29.61(s). 31 P NMR (162MHz, CDCl3) δ33.47 (s).

[0102] Example 15

[0103]

[0104] Under nitrogen protection, 1 mmol (0.1744 g) of 1-phenyl-2-hexen-1-one and 1.2 mmol (0.2424 g) of diphenylphosphine oxide were added to a 10 mL Schlenk flask, followed by 5 mmol (0.0215 g) of the obtained catalyst crystals, and finally 2.5 mL of anhydrous toluene. The resulting solution was reacted in an oil bath at 80 °C for 3 hours. After cooling, the solvent was removed to obtain a yellow crude product. The crude product was separated by column chromatography (dichloromethane:methanol = 30:1) to give 342 mg (91% yield, 0.91 mmol) of a pale yellow powder.

[0105] 1H NMR (400MHz, CDCl3) δ7.85-7.70(m,6H),7.49-7.37(m,4H),7.37-7.25(m,5H),3.45-3.32(m,1H), 3.30-3.06(m,2H),1.69-1.40(m,2H),1.30-1.14(m,1H),1.14-1.00(m,1H),0.69(t,J=7.3Hz,3H). 13 C NMR (101MHz, CDCl3) δ197.61(d,J=10.9Hz),136.35(s),133.35(s),132.75(d,J=20.5Hz),132.92-131.77(m),131.82-131.47(m),130.93(dd,J=8 .7,1.3Hz),128.71(dd,J=11.3,1.3Hz),128.34(d,J=51.4Hz),37.06(s), 31.50(d,J=73.1Hz), 30.92(d,J=1.9Hz), 20.98(d,J=11.0Hz), 14.03(s). 31 P NMR (162MHz, CDCl3) δ37.36 (s).

[0106] Example 16

[0107]

[0108] Under nitrogen protection, 1 mmol (0.1462 g) of 4-phenyl-3-buten-2-one and 1.2 mmol (0.3144 g) of bis(4-methoxyphenyl)phosphine oxide were added to a 10 mL Schlenk flask, followed by 5 mmol (0.0215 g) of the obtained catalyst crystals, and finally 2.5 mL of anhydrous toluene. The resulting solution was reacted in an oil bath at 80 °C for 3 hours. After cooling, the solvent was removed to obtain a yellow crude product. The crude product was separated by column chromatography (dichloromethane:methanol = 30:1) to give 388 mg (95% yield, 0.95 mmol) of a white powder.

[0109] 1H NMR (400MHz, CDCl3) δ7.86-7.77(m,2H),7.34-7.24(m,4H),7.20-7.10(m,3H),7.02(dd,J=8.8,2.2Hz,2H),6.73(dd,J=8.9,2.3Hz,2H),4.12( ddd,J=10.4,7.8,2.9Hz,1H),3.85(s,3H),3.73(s,3H),3.29(ddd,J=17.8,10.2,5.4Hz,1H),2.95(ddd,J=17.9,11.2,2.9Hz,1H),1.95(s,3H). 1 H NMR (400MHz, CDCl3) δ7.86-7.77(m,2H),7.34-7.24(m,4H),7.20-7.10(m,3H),7.02(dd,J=8.8,2.2Hz,2H),6.73(dd,J=8.9,2.3Hz,2H),4.12( ddd,J=10.4,7.8,2.9Hz,1H),3.85(s,3H),3.73(s,3H),3.29(ddd,J=17.8,10.2,5.4Hz,1H),2.95(ddd,J=17.9,11.2,2.9Hz,1H),1.95(s,3H). 31 P NMR (162MHz, CDCl3) δ33.78 (s).

[0110] Example 17

[0111]

[0112] Under nitrogen protection, 1 mmol (0.1462 g) of 4-phenyl-3-buten-2-one and 1.2 mmol (0.2762 g) of bis(4-methylphenyl)phosphine were added to a 10 mL Schlenk flask, followed by 5 mmol (0.0215 g) of the obtained catalyst crystals, and finally 2.5 mL of anhydrous toluene. The resulting solution was reacted in an oil bath at 80 °C for 3 hours. After cooling, the solvent was removed to obtain a yellow crude product. The crude product was separated by column chromatography (dichloromethane:methanol = 30:1) to give 376 mg (95% yield, 0.95 mmol) of a white powder.

[0113] 1H NMR (400MHz, CDCl3) δ7.71(dd,J=10.5,8.1Hz,2H),7.29-7.20(m,6H),7.11-7.01(m,3H),6.95(dd,J=8.0,2.6Hz,2H),4.09(ddd,J=10 .3,7.5,2.9Hz,1H),3.23(ddd,J=17.8,10.2,5.3Hz,1H),2.85(ddd,J=17.9,11.1,2.9Hz,1H),2.33(s,3H),2.17(s,3H),1.86(s,3H). 13 C NMR (101MHz, CDCl3) δ204.48 (d, J = 12.8Hz), 141.03 (dd, J = 67.1, 2.8Hz), 135. 12(d,J=5.5Hz),130.11(dd,J=29.1,9.0Hz),128.74(d,J=5.7Hz),128.17(dd ,J=79.0,11.9Hz),127.85(d,J=11.0Hz),127.27(d,J=1.8Hz),125.98(d,J=2 .4Hz), 42.66(s), 40.25(d,J=68.8Hz), 29.58(s), 20.49(dd,J=12.8,1.0Hz). 31 P NMR (162MHz, CDCl3) δ33.96 (s).

[0114] Example 18

[0115]

[0116] Under nitrogen protection, 1 mmol (0.1462 g) of 4-phenyl-3-buten-2-one and 1.2 mmol (0.2762 g) of bis(2-methylphenyl)phosphine were added to a 10 mL Schlenk flask, followed by 5 mmol (0.0215 g) of the obtained catalyst crystals, and finally 2.5 mL of anhydrous toluene. The resulting solution was reacted in an oil bath at 80 °C for 3 hours. After cooling, the solvent was removed to obtain a yellow crude product. The crude product was separated by column chromatography (dichloromethane:methanol = 30:1) to give 199 mg (53% yield, 0.53 mmol) of a white powder.

[0117] 1H NMR (400MHz, CDCl3) δ7.72(dd,J=11.0,7.7Hz,1H),7.44-7.31(m,2H),7.26(t,J=6.2Hz,3H),7.16-6.98(m,5H),6.94(t,J=7.0Hz,1H),6.85(dd,J=7 .4,4.4Hz,1H),4.41-4.32(m,1H),3.40(ddd,J=18.1,10.1,4.3Hz,1H),3. 15(ddd,J=18.2,10.6,2.4Hz,1H),2.28(s,3H),2.04(s,3H),1.95(s,3H). 13 C NMR (101MHz, CDCl3) δ204.77 (d, J = 12.6Hz), 141.47 (dd, J = 138.0, 7.9Hz), 131.49 (dd, J =10.3,5.2Hz),130.78(d,J=2.5Hz),130.30(dd,J=10.0,8.0Hz),130.20-130.00(m),1 29.49(s),128.60(d,J=5.8Hz),127.25(d,J=1.8Hz),126.03(d,J=2.3Hz),124.27(dd, J=55.5,11.7Hz),43.51(s),38.54(d,J=69.4Hz),29.80(s),20.13(dd,J=36.0,3.8Hz). 31 P NMR(162MHz, CDCl3)δ37.17(s).

[0118] Example 19

[0119]

[0120] Under nitrogen protection, 1 mmol (0.1462 g) of 4-phenyl-3-buten-2-one and 1.2 mmol (0.2762 g) of bis(3-methylphenyl)phosphine were added to a 10 mL Schlenk flask, followed by 5 mmol (0.0215 g) of the obtained catalyst crystals, and finally 2.5 mL of anhydrous toluene. The resulting solution was reacted in an oil bath at 80 °C for 3 hours. After cooling, the solvent was removed to obtain a yellow crude product. The crude product was separated by column chromatography (dichloromethane:methanol = 30:1) to give 279 mg (74% yield, 0.74 mmol) of a white powder.

[0121] 1H NMR(400MHz, CDCl3)δ7.69(d,J=11.3Hz,1H),7.60(dd,J=9.3,8.6Hz,1H),7.35-7.24(m,2H),7.24-7.19(m,2H),7.18-7.00(m,7H),4.11(dd d,J=10.2,7.4,2.8Hz,1H),3.25(ddd,J=17.8,10.3,5.3Hz,1H),2.84(ddd,J=17.9,11.0,2.8Hz,1H),2.33(s,3H),2.10(s,3H),1.86(s,3H). 13 C NMR (101MHz, CDCl3) δ205.44 (d, J = 12.9Hz), 138.35 (dd, J = 96.2, 11.4Hz), 136.00 (d, J = 5 .6Hz),132.48(dd,J=59.2,2.8Hz),132.11-131.60(m),130.79(d,J=2.1Hz),129.75(d, J=5.6Hz),128.39(dd,J=61.7,10.5Hz),128.28(d,J=1.9Hz),127.85(dd,J=11.0,5.1Hz ), 127.05 (d, J = 2.4Hz), 43.54 (s), 41.15 (d, J = 68.3Hz), 30.63 (s), 21.35 (d, J = 28.3Hz). 31 P NMR (162MHz, CDCl3) δ33.94 (s).

[0122] Example 20

[0123]

[0124] Under nitrogen protection, 1 mmol (0.1462 g) of 4-phenyl-3-buten-2-one and 1.2 mmol (0.3096 g) of bis(4-ethylphenyl)phosphine were added to a 10 mL Schlenk flask, followed by 5 mmol (0.0215 g) of the obtained catalyst crystals, and finally 2.5 mL of anhydrous toluene. The resulting solution was reacted in an oil bath at 80 °C for 3 hours. After cooling, the solvent was removed to obtain a yellow crude product. The crude product was separated by column chromatography (dichloromethane:methanol = 30:1) to give 206 mg (51% yield, 0.51 mmol) of a white powder.

[0125] 1H NMR (400MHz, CDCl3) δ7.74 (dd, J=10.5, 8.1Hz, 2H), 7.30-7.20 (m, 6H), 7.12-7.02 ( m,3H),6.98(dd,J=8.1,2.5Hz,2H),4.10(ddd,J=10.3,7.5,2.8Hz,1H),3.24(ddd,J =17.6,10.3,5.3Hz,1H),2.86(ddd,J=17.8,11.0,2.8Hz,1H),2.63(q,J=7.6Hz,2H ),2.48(q,J=7.6Hz,2H),1.87(s,3H),1.18(t,J=7.6Hz,3H),1.06(t,J=7.6Hz,3H). 13 C NMR (101MHz, CDCl3) δ204.58 (d, J = 12.8Hz), 147.19 (dd, J = 63.4, 2.7Hz), 135.09 (d, J = 5. 5Hz),130.20(dd,J=30.1,9.0Hz),128.73(d,J=5.6Hz),127.53(dd,J=99.8,10.5Hz),12 7.25(d,J=1.8Hz),126.98(dd,J=80.0,11.9Hz),125.96(d,J=2.3Hz),125.96(d,J=2.3H z), 42.61 (s), 40.29 (d, J = 68.6Hz), 29.63 (s), 27.76 (d, J = 14.6Hz), 14.07 (d, J = 8.5Hz). 31 P NMR(162MHz, CDCl3)δ33.92(s).

[0126] Example 21

[0127]

[0128] Under nitrogen protection, 1 mmol (0.1462 g) of 4-phenyl-3-buten-2-one and 1.2 mmol (0.3100 g) of bis(3,5-dimethylphenyl)phosphine oxide were added to a 10 mL Schlenk flask, followed by 5 mmol (0.0215 g) of the obtained catalyst crystals, and finally 2.5 mL of anhydrous toluene. The resulting solution was reacted in an oil bath at 80 °C for 3 hours. After cooling, the solvent was removed to obtain a yellow crude product. The crude product was separated by column chromatography (dichloromethane:methanol = 30:1) to give 214 mg (53% yield, 0.53 mmol) of a white powder.

[0129] 1H NMR (400MHz, CDCl3) δ7.43(d,J=11.0Hz,2H),7.26-7.18(m,2H),7.07(tt,J=14.3,7.1Hz,4H),6.94(d,J=11.5Hz,2H),6.86(s,1H),4.08(dd d,J=10.3,7.4,2.8Hz,1H),3.23(ddd,J=17.7,10.3,5.2Hz,1H),2.83(ddd,J=17.8,10.9,2.8Hz,1H),2.30(s,6H),2.09(s,6H),1.87(s,3H). 13 C NMR(101MHz,CDCl3)δ205.55(d,J=12.9Hz),138.06(dd,J=94.8,12.2Hz),136 .21(d,J=5.5Hz),133.37(dd,J=59.3,2.9Hz),131.24(dd,J=96.7,9.9Hz),12 9.78(d,J=5.6Hz),128.75(dd,J=18.3,8.7Hz),128.20(d,J=1.8Hz),126.95( d,J=2.4Hz), 43.58(s), 41.20(d,J=68.0Hz), 30.63(s), 21.24(d,J=25.0Hz). 31 PNMR (162MHz, CDCl3) δ 34.12 (s).

[0130] Example 22

[0131]

[0132] Under nitrogen protection, 1 mmol (0.1462 g) of 4-phenyl-3-buten-2-one and 1.2 mmol (0.3268 g) of dinaphthylphosphine were added to a 10 mL Schlenk flask, followed by 5 mmol (0.0215 g) of the obtained catalyst crystals, and finally 2.5 mL of anhydrous toluene. The resulting solution was reacted in an oil bath at 80 °C for 3 hours. After cooling, the solvent was removed to obtain a yellow crude product. The crude product was separated by column chromatography (dichloromethane:methanol = 30:1) to give 139 mg (31% yield, 0.31 mmol) of a white powder.

[0133] 1H NMR(400MHz, CDCl3) δ8.55(d,J=12.7Hz,1H),8.01(d,J=13.2Hz,1H),7.95-7.88 (m,2H),7.82(q,J=9.8Hz,2H),7.70-7.59(m,3H),7.59-7.47(m,2H),7.46-7.26 (m,5H),7.05(dt,J=20.2,7.0Hz,3H),4.39(ddd,J=9.9,7.3,2.6Hz,1H),3.33(d dd,J=17.6,10.2,5.2Hz,1H),2.94(ddd,J=17.9,11.3,2.6Hz,1H),1.86(s,3H). 13 C NMR (101MHz, CDCl3) δ205.34 (d, J = 12.8Hz), 135.90 (d, J = 5.6Hz), 134.56 (dd, J = 37.2, 2.3Hz) ,133.51(dd,J=40.1,7.7Hz),132.50(dd,J=44.1,12.6Hz),129.81(d,J=5.7Hz),128.97(dt, J=11.1,7.3Hz),128.38(dd,J=18.5,9.1Hz),127.87(d,J=11.6Hz),127.23(d,J=2.4Hz),126 .91(d,J=46.8Hz), 126.85(dd,J=218.4,10.4Hz), 43.73(s), 40.99(d,J=68.9Hz), 30.64(s). 31 P NMR (162MHz, CDCl3) δ34.00 (s).

[0134] The above embodiments are merely preferred embodiments of the present invention, and the scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A method for the catalytic synthesis of γ-ketophosphine oxides from asymmetric alkylaluminum compounds under mild conditions, characterized in that... Within the temperature range of 60℃ to 100℃ and in the presence of organic solvents, phosphine oxides are reacted with α,β-unsaturated ketones as raw materials and asymmetric alkylaluminum compounds as catalysts to generate γ-ketophosphine oxides. The phosphine oxychloride compound has the following structural formula: The asymmetric alkylaluminum compound has the following structural formula: The α,β-unsaturated ketone has the following structural formula: The γ-ketophosphine oxide has the following structural formula: Among them, R1 is selected from methyl, methoxy, ethoxy, R x Substituted phenyl or naphthyl groups; R x Selected from halogens, methoxy groups, methyl groups, and ethyl groups; R2 is selected from 2,6-diisopropylphenyl, 2,6-diethylphenyl, and 2,4,6-trimethylphenyl; R3 is selected from methyl, ethyl, and isobutyl; R4 is selected from phenyl, R x Substituted phenyl, naphthyl, cyclohexyl, n-propyl, styryl, phenylethynyl, 2-pyridyl, 2-thienyl; R x Selected from halogen, methyl, hydroxy, nitro, trifluoromethyl, methoxy, cyano, and dimethylamino; R5 is selected from phenyl, R x Substituted phenyl, methyl, n-butyl, tert-butyl; R x Selected from halogens and methoxy groups.

2. The method for synthesizing γ-ketophosphine oxide according to claim 1, characterized in that: The alkyl group in the asymmetric alkylaluminum metal catalyst is methyl or ethyl, and the ligand stabilizing the metal center is an asymmetric β-diimine ligand.

3. The method for synthesizing γ-ketophosphine oxide according to claim 1, characterized in that: The molar ratio of the α,β-unsaturated ketone to phosphine oxide is 1:1 to 1:1.

2.

4. The method for synthesizing γ-ketophosphine oxide according to claim 1, characterized in that: The molar ratio of the α,β-unsaturated ketone to the asymmetric alkyl aluminum compound is 1:0.01 to 1:0.

1.

5. The method for synthesizing γ-ketophosphine oxide according to claim 1, characterized in that: The organic solvents used are n-hexane, tetrahydrofuran, toluene, and chloroform.

6. The method for synthesizing γ-ketophosphine oxide according to claim 1, characterized in that: The reaction temperature is 60℃~100℃, and the reaction time is 2~10h.

7. The method for synthesizing γ-ketophosphine oxide according to claim 1, characterized in that: The reaction process involves no transition metals and no external acids or bases.

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