Method for green catalytic synthesis of gamma-ketophosphine oxide from asymmetric alkyl aluminum compound

Abstract

The invention discloses a method for green catalytic synthesis of gamma-ketophosphine oxide from an asymmetric alkyl aluminum compound under mild conditions. The method comprises the following steps: in the presence of an organic solvent in a temperature range of 60-100 DEG C, taking a phosphine oxide compound as a raw material, taking an asymmetric alkyl aluminum compound as a catalyst, and reacting with alpha, beta-unsaturated ketone to generate the gamma-ketophosphine oxide. The method disclosed by the invention has the characteristics of mild reaction conditions, high product yield, wide substrate range, no additional acid, alkali or heavy metal and the like, and meets the requirements of green chemistry and atom economy reaction.

Description

Technical Field

[0001] The invention relates to a method for green catalytic synthesis of gamma-ketophosphine oxide using an asymmetric alkyl aluminum compound, and specifically belongs to the field of green catalysis and drug synthesis intermediates. Background Art

[0002] Organophosphorus compounds are widely used in organic synthesis, medicinal chemistry, agricultural chemistry and materials science. Among them, γ-ketophosphorus oxides have attracted widespread attention in the fields of organic and medicinal chemistry in the past few decades due to their unique structural characteristics and diverse and interesting biological properties. The traditional synthesis method of γ-ketophosphorus oxides mainly relies on the Phospha-Michael reaction, i.e., the phosphonylation reaction of α, β-unsaturated carbonyl compounds with nucleophilic phosphine reagents, which often relies on strong acids, strong bases, and precious metals for catalysis, and the substrate range is limited. These catalysts are relatively expensive and harmful to the environment, and cannot fully meet the requirements of industrial production and sustainable development (G. Strappaveccia, 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-Michael Reaction

[0004]

[0005] Aluminum has the characteristics of abundant reserves, low price, and low biological toxicity. With the development of green chemistry, main group metal catalysts such as aluminum and magnesium have become one of the research hotspots. To this end, we have invented a catalyst with an asymmetric alkyl aluminum structure, which can catalyze the Phospha-Michael reaction in a green and efficient manner to obtain γ-ketophosphine oxides, and has the characteristics of high activity, no pollution, and strong substrate tolerance. Summary of the invention

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

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

[0008] The purpose of the present invention is to provide a method for generating γ-ketophosphine oxide by reacting phosphine oxide compound with α, β-unsaturated ketone under the catalysis of asymmetric alkyl aluminum compound.

[0009] The method of the present invention is further described as: using a phosphine oxide compound as a raw material and an asymmetric alkyl aluminum compound as a catalyst to react with an α, β-unsaturated ketone in the presence of an organic solvent at a temperature in the range of 60°C to 100°C to generate a γ-ketophosphine oxide;

[0010] The molar ratio of the phosphine oxide compound, the α,β-unsaturated ketone, and the asymmetric alkyl aluminum compound is 1-1.2:1:0.01-0.01;

[0011] The asymmetric alkyl aluminum compound used in the present invention has the following structural formula:

[0012]

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

[0014] The phosphine oxide compound used in the present invention has the following structural formula:

[0015]

[0016] Wherein, R1 is selected from methyl, methoxy, ethoxy, R x Substituted phenyl, naphthyl; X is selected from halogen, methoxy, methyl, ethyl;

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

[0018]

[0019] Wherein R4 is selected from phenyl, R x Substituted phenyl, naphthyl, cyclohexyl, n-propyl, styryl, phenylethynyl, 2-pyridyl, 2-thienyl; X is selected from halogen, methyl, hydroxy, 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 para, ortho or meta, and the number of substitutions is 1 or 2;

[0023] The structure of the asymmetric alkyl aluminum catalyst used in the present invention is as described above. The aromatic group R2 connected to the N atoms at both ends is recommended to be 2,4,6-trimethylphenyl, and the alkyl group R3 connected to the aluminum atom is recommended to be methyl or ethyl. It is further recommended that R3 is methyl.

[0024] The structure of the α,β-unsaturated ketone used in the present invention is as described above, and the group R4 connected to the β-carbon atom is preferably a phenyl group, R x Substituted phenyl, naphthyl, 2-pyridyl, 2-thienyl; the R x The substituted phenyl group is preferably halogen, methyl, hydroxy, nitro, trifluoromethyl, methoxy, cyano, dimethylamino, and further preferably methyl, hydroxy, nitro, trifluoromethyl, methoxy; the group R5 connected to the ketone carbon atom is preferably phenyl or R x substituted phenyl, methyl, n-butyl, tert-butyl;

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

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

[0027] The alkyl aluminum catalyst used in the method of the present 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 of the method of the present invention is 60°C to 100°C, and the recommended reaction temperature is 80°C;

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

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

[0031] The reaction time in the method of the present 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 reduced pressure filtration, recrystallization, thin layer chromatography and column chromatography.

[0033] If separation is performed by recrystallization, the recommended solvent is a mixed solvent of polar solvent and non-polar solvent, and the recommended solvent is ethyl acetate-petroleum ether; when separation is performed by thin layer chromatography or column chromatography, the recommended solvent is a mixed solvent of dichloromethane-methanol, and the recommended ratio of dichloromethane to methanol is 16:1;

[0034] The present invention provides a method for obtaining various γ-ketophosphine oxides by reacting a phosphine oxide compound with an α, β-unsaturated ketone under the catalysis of an asymmetric alkyl aluminum compound, with low pollution, high yield and high substrate tolerance. Compared with the existing methods, the present invention has the following beneficial effects:

[0035] (1) The present invention first discovered that alkyl aluminum compounds supported by β-diimine ligands can efficiently catalyze the Phospha-Michael reaction under mild reaction conditions without the addition of external acid, base or heavy metals, which meets the requirements of green chemistry and atom-economic reactions;

[0036] (2) The catalyst of the present invention uses main group metal aluminum, which is abundant, cheap, 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 alkyl aluminum catalyst of the present invention is simple to prepare. It can be obtained by simply dissolving the ligand and reacting it with the alkyl aluminum reagent in one step. After the solvent is drained, it can be used directly without further separation.

[0038] (4) The present invention overcomes the difficulty of the narrow substrate range of the Phospha-Michael reaction catalyzed by traditional catalysts. The asymmetric alkyl aluminum catalyst mentioned in the method of the present invention is used to catalyze the Phospha-Michael reaction. A yield of up to 99% can be provided after a reaction of 6 h at a 1 mol% catalytic loading. The reaction also has the characteristics of a wide substrate range and easy separation after the reaction. DETAILED DESCRIPTION

[0039] The present invention is described in detail below in conjunction with the embodiments, but it should be understood that the embodiments are only used to exemplify the present invention and do not constitute any limitation on the protection scope of the present invention. All reasonable changes and combinations included in the scope of the invention spirit of the present invention fall within the protection scope of the present invention.

[0040] The asymmetric β-diimine ligand used in the following examples has the following structure:

[0041]

[0042] The asymmetric alkyl aluminum 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 an asymmetric β-diimine ligand L3 and 1 mL of a n-hexane solution of trimethylaluminum (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 for 11 to 13 hours to obtain an aluminum methyl compound solution stabilized by the asymmetric β-diimine ligand L3;

[0047] (2) The aluminum methyl compound solution stabilized by the asymmetric β-diimine ligand L3 was concentrated to 5 mL and refrigerated at -15°C to 5°C for 24 hours for crystallization 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, 1mmol (0.1462g) 4-phenyl-3-butene-2-one and 1.2mmol (0.2424g) diphenylphosphine oxide were added to a 10mL Schlenk reaction bottle, followed by 5mmol% (0.0215g) of the catalyst crystals obtained, and finally 2.5mL of anhydrous toluene. The resulting solution was reacted in an oil bath at 80°C for 3 hours, and the solvent was drained after the solution was cooled to obtain a yellow crude product. The crude product was separated by column, dichloromethane: methanol = 30:1, and 331mg (95% yield, 0.95mmol) of white powder was obtained.

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

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

[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, 1mmol (0.2251g) 4-(4-bromophenyl)-3-butene-2-one and 1.2mmol (0.2424g) diphenylphosphine oxide were added to a 10mL Schlenk reaction bottle, followed by 5mmol% (0.0215g) of the catalyst crystals obtained, and finally 2.5mL of anhydrous toluene. The resulting solution was reacted in an oil bath at 80°C for 3 hours, and after the solution was cooled, the solvent was drained to obtain a yellow crude product. The crude product was separated by column, dichloromethane: methanol = 30:1, to obtain 375mg (88% yield, 0.88mmol) of 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, 1mmol (0.1762g) 4-(4-methoxyphenyl)-3-butene-2-one and 1.2mmol (0.2424g) diphenylphosphine oxide were added to a 10mL Schlenk reaction bottle, followed by 5mmol% (0.0215g) of the catalyst crystals obtained, and finally 2.5mL of anhydrous toluene. The resulting solution was reacted in an oil bath at 80°C for 3 hours, and after the solution was cooled, the solvent was drained to obtain a yellow crude product. The crude product was separated by column, dichloromethane: methanol = 30:1, to obtain 359mg (95% yield, 0.95mmol) of 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, 1mmol (0.1712g) 4-(4-cyanophenyl)-3-butene-2-one and 1.2mmol (0.2424g) diphenylphosphine oxide were added to a 10mL Schlenk reaction bottle, followed by 5mmol% (0.0215g) of the catalyst crystals obtained, and finally 2.5mL of anhydrous toluene. The resulting solution was reacted in an oil bath at 80°C for 3 hours, and after the solution was cooled, the solvent was drained to obtain a yellow crude product. The crude product was separated by column, dichloromethane: methanol = 30:1, to obtain 358mg (96% yield, 0.96mmol) of 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, 1mmol (0.1893g) 4-(4-dimethylaminophenyl)-3-butene-2-one and 1.2mmol (0.2424g) diphenylphosphine oxide were added to a 10mL Schlenk reaction bottle, followed by 5mmol% (0.0215g) of the catalyst crystals obtained, and finally 2.5mL of anhydrous toluene. The resulting solution was reacted in an oil bath at 80°C for 3 hours, and after the solution was cooled, the solvent was drained to obtain a yellow crude product. The crude product was separated by column, dichloromethane: methanol = 30:1, to obtain 301mg (77% yield, 0.77mmol) of light 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, 1mmol (0.1602g) 4-(2-methylphenyl)-3-butene-2-one and 1.2mmol (0.2424g) diphenylphosphine oxide were added to a 10mL Schlenk reaction bottle, followed by 5mmol% (0.0215g) of the catalyst crystals obtained, and finally 2.5mL of anhydrous toluene. The resulting solution was reacted in an oil bath at 80°C for 3 hours, and after the solution was cooled, the solvent was drained to obtain a yellow crude product. The crude product was separated by column, dichloromethane: methanol = 30:1, to obtain 355mg (98% yield, 0.98mmol) of 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, 1mmol (0.1602g) 4-(3-methylphenyl)-3-butene-2-one and 1.2mmol (0.2424g) diphenylphosphine oxide were added to a 10mL Schlenk reaction bottle, followed by 5mmol% (0.0215g) of the catalyst crystals obtained, and finally 2.5mL of anhydrous toluene. The resulting solution was reacted in an oil bath at 80°C for 3 hours, and after the solution was cooled, the solvent was drained to obtain a yellow crude product. The crude product was separated by column, dichloromethane: methanol = 30:1, and 351mg (97% yield, 0.97mmol) of white powder was obtained.

[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] Embodiment 11

[0087]

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

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

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

[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] Embodiment 14

[0099]

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

[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] Embodiment 15

[0103]

[0104] Under nitrogen protection, add 1mmol (0.1744g) 1-phenyl-2-hexene-1-one and 1.2mmol (0.2424g) diphenylphosphine oxide to a 10mL Schlenk reaction bottle, then add 5mmol% (0.0215g) of the obtained catalyst crystals, and finally add 2.5mL of anhydrous toluene. The resulting solution is reacted in an oil bath at 80°C for 3 hours, and the solvent is drained after the solution is cooled to obtain a yellow crude product. The crude product is separated by column, dichloromethane: methanol = 30:1, and 342mg (91% yield, 0.91mmol) of light yellow powder is obtained.

[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, 1mmol (0.1462g) 4-phenyl-3-butene-2-one and 1.2mmol (0.3144g) di(4-methoxyphenyl)phosphine oxide were added to a 10mL Schlenk reaction bottle, followed by 5mmol% (0.0215g) of the catalyst crystals obtained, and finally 2.5mL of anhydrous toluene. The resulting solution was reacted in an oil bath at 80°C for 3 hours, and after the solution was cooled, the solvent was drained to obtain a yellow crude product. The crude product was separated by column, dichloromethane: methanol = 30:1, and 388mg (95% yield, 0.95mmol) of white powder was obtained.

[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] Embodiment 17

[0111]

[0112] Under nitrogen protection, 1mmol (0.1462g) 4-phenyl-3-butene-2-one and 1.2mmol (0.2762g) di(4-methylphenyl)phosphine oxide were added to a 10mL Schlenk reaction bottle, followed by 5mmol% (0.0215g) of the catalyst crystals obtained, and finally 2.5mL of anhydrous toluene. The resulting solution was reacted in an oil bath at 80°C for 3 hours, and after the solution was cooled, the solvent was drained to obtain a yellow crude product. The crude product was separated by column, dichloromethane: methanol = 30:1, to obtain 376mg (95% yield, 0.95mmol) of 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] Embodiment 18

[0115]

[0116] Under nitrogen protection, 1mmol (0.1462g) 4-phenyl-3-butene-2-one and 1.2mmol (0.2762g) di(2-methylphenyl)phosphine oxide were added to a 10mL Schlenk reaction bottle, followed by 5mmol% (0.0215g) of the catalyst crystals obtained, and finally 2.5mL of anhydrous toluene. The resulting solution was reacted in an oil bath at 80°C for 3 hours, and the solvent was drained after the solution was cooled to obtain a yellow crude product. The crude product was separated by column, dichloromethane: methanol = 30:1, to obtain 199mg (53% yield, 0.53mmol) of 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] Embodiment 19

[0119]

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

[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] Embodiment 20

[0123]

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

[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] Embodiment 21

[0127]

[0128] Under nitrogen protection, add 1mmol (0.1462g) 4-phenyl-3-butene-2-one and 1.2mmol (0.3100g) di(3,5-dimethylphenyl)phosphine oxide to a 10mL Schlenk reaction bottle, then add 5mmol% (0.0215g) of the obtained catalyst crystals, and finally add 2.5mL of anhydrous toluene. The resulting solution was reacted in an oil bath at 80°C for 3 hours, and the solvent was drained after the solution was cooled to obtain a yellow crude product. The crude product was separated by column, dichloromethane: methanol = 30:1, and 214mg (53% yield, 0.53mmol) of white powder was obtained.

[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)δ34.12(s).

[0130] Embodiment 22

[0131]

[0132] Under nitrogen protection, add 1mmol (0.1462g) 4-phenyl-3-butene-2-one and 1.2mmol (0.3268g) dinaphthylphosphine oxide to a 10mL Schlenk reaction bottle, then add 5mmol% (0.0215g) of the obtained catalyst crystals, and finally add 2.5mL of anhydrous toluene. The resulting solution is reacted in an oil bath at 80°C for 3 hours, and after the solution is cooled, the solvent is drained to obtain a yellow crude product. The crude product is separated by column, dichloromethane: methanol = 30:1, and 139mg (31% yield, 0.31mmol) of white powder is obtained.

[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 only preferred implementations of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A method for green catalytic synthesis of γ-ketophosphine oxides using asymmetric alkyl aluminum compounds under mild conditions, characterized in that In the presence of an organic solvent and at a temperature of 60°C to 100°C, a phosphine oxide compound is used as a raw material and an asymmetric alkyl aluminum compound is used as a catalyst to react with an α, β-unsaturated ketone to generate a γ-ketophosphine oxide. The phosphine oxide compound has the following structural formula: The asymmetric alkyl aluminum 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: Wherein, R1 is selected from methyl, methoxy, ethoxy, R x Substituted phenyl, naphthyl; X is selected from halogen, methoxy, methyl, ethyl; R2 is selected from 2,6-diisopropylphenyl, 2,6-diethylphenyl, 2,4,6-trimethylphenyl; R3 is selected from methyl, ethyl, isobutyl; R4 is selected from phenyl, R x substituted phenyl, naphthyl, cyclohexyl, n-propyl, styryl, phenylethynyl, 2-pyridyl, 2-thienyl; X is selected from halogen, methyl, hydroxy, nitro, trifluoromethyl, methoxy, cyano, dimethylamino; R5 is selected from phenyl, R x substituted phenyl, methyl, n-butyl, tert-butyl; X is selected from halogen and methoxy.

2. The method for synthesizing γ-ketophosphine oxide according to claim 1, characterized in that The alkyl group in the asymmetric alkyl aluminum 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 the 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 temperature of the reaction process is 60°C to 100°C, and the reaction time is 2 to 10 hours.

7. The method for synthesizing γ-ketophosphine oxide according to claim 1, characterized in that: The reaction process does not involve transition metals and does not require external acid or alkali.

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