Synthesis method of polyketone ligand

Abstract

The invention relates to a synthesis method of a polyketone ligand, which comprises the following steps: a) reacting 2-bromo-1, 3-dimethoxybenzene, magnesium powder and phosphorus chloride in a solvent to obtain chlorine bis (2, 6-dimethoxyphenyl) phosphine; b) reacting the chlorine bis (2, 6-dimethoxyphenyl) phosphine obtained in the step a) with alkylamine to obtain 1, 1-bis (2, 6-dimethoxyphenyl)-N-alkyl phosphinamine; and c) carrying out a reaction on the 1, 1-bis (2, 6-dimethoxyphenyl)-N-alkyl phosphinamine obtained in the step b) and diphenyl phosphinyl chloride to obtain the polyketone ligand N-(bis (2, 6-dimethoxyphenyl) phosphonyl)-N-alkyl-P, P-diphenyl phosphinamide. Specific raw materials are selected to synthesize the polyketone ligand according to specific process steps, the reaction route and the post-treatment process are simple, required equipment is simple, energy consumption is low, overall good interaction can be achieved, and the product is high in yield, good in quality, safe and easy to industrialize.

Description

Technical Field

[0001] The invention belongs to the field of fine chemicals and relates to a method for synthesizing a polyketone ligand, in particular to a method for synthesizing a polyketone ligand N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-alkyl-P,P-diphenylphosphamide. Background Art

[0002] Polyketone is a polymer material copolymerized by the reaction of ethylene and carbon monoxide (CO). It has excellent impact strength, chemical resistance, high temperature resistance, wear resistance and gas barrier ability, so it is used in many fields such as product packaging, mechanical parts, and electronic devices. Ethylene is a cheap and readily available raw material in industry, and CO is an important carbon-one resource. This copolymerization reaction can not only effectively save coal and oil resources, but also reasonably utilize the CO by-products produced in chemical and chemical processes. At present, the catalyst used in the production of commercial polyketone materials is a cationic palladium complex chelated by a bisphosphine ligand. However, this process has problems such as the inactivation of precious metal palladium ions due to easy reduction, and the difficult-to-recover palladium metal will remain on the polyketone material and affect further processing. Therefore, researchers are committed to developing cheap alternative metal nickel complexes. In 2022, our research group (Chen SY, Ren BH, Li SH, et al. Cationic P, O-Coordinated Nickel (II) Catalysts for Carbonylative Polymerization of Ethylene: Unexpected Productivity via Subtle Electronic Variation [J]. Angewandte Chemie International Edition, 2022, e202204126.) designed and synthesized a series of phosphine-phosphoramide (PNPO) type cationic nickel complexes, which have good effects in the copolymerization of ethylene and CO. The PNPO ligand with higher catalytic activity used is N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-(4-(dimethylamino)phenyl)-P,P-diphenylphosphamide. At present, the method for preparing the ligand is to react N,N-dimethyl-p-phenylenediamine with diphenylphosphinyl chloride to generate N-(4-(dimethylamino)phenyl)-P,P-diphenylphosphinamide, 2-bromo-1,3-dimethoxybenzene with dichlorodiethylaminophosphine to synthesize 1,1-bis(2,6-dimethoxyphenyl)-N,N-diethylphosphinamide, and then deprotect with hydrogen chloride, hydrochloric acid and ethyl acetate to obtain chlorobis(2,6-dimethoxyphenyl)phosphine. N-(4-(dimethylamino)phenyl)-P,P-diphenylphosphinamide reacts with chlorobis(2,6-dimethoxyphenyl)phosphine to obtain the target ligand.

[0003] In the above preparation method, n-butyl lithium, which is expensive and has potential safety hazards, and other various raw materials and reagents need to be used three times, and the route is long and the cost is high. In addition, this method requires the use of column chromatography to purify the ligand, and the yield is low. Therefore, this method is not suitable for industrial mass production.

[0004] Therefore, the development of an alternative synthetic route is essential for the synthesis of polyketones. Summary of the invention

[0005] In view of this, the object of the present invention is to provide a method for synthesizing a polyketone ligand N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-alkyl-P,P-diphenylphosphamide, which has a simple reaction route and post-treatment process, low cost, high product yield and good quality.

[0006] The technical solution of the present invention:

[0007] A method for synthesizing a polyketone ligand is a method for synthesizing a polyketone ligand N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-alkyl-P,P-diphenylphosphamide, wherein:

[0008] The structure of N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-alkyl-P,P-diphenylphosphinamide is as follows:

[0009]

[0010] Among them, R is methyl, ethyl, benzyl, propyl, isopropyl, n-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, cyclohexyl and the like.

[0011] The synthetic route is as follows:

[0012]

[0013] The specific steps are as follows:

[0014] a) reacting 2-bromo-1,3-dimethoxybenzene, magnesium powder and phosphorus chloride in a solvent to obtain chlorobis(2,6-dimethoxyphenyl)phosphine;

[0015] b) reacting the chlorobis(2,6-dimethoxyphenyl)phosphine obtained in step a) with an alkylamine to obtain 1,1-bis(2,6-dimethoxyphenyl)-N-alkylphosphineamine.

[0016] c) reacting the 1,1-bis(2,6-dimethoxyphenyl)-N-alkylphosphinamide obtained in step b) with diphenylphosphinyl chloride to obtain a polyketone ligand N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-alkyl-P,P-diphenylphosphinamide.

[0017] The present invention first reacts 2-bromo-1,3-dimethoxybenzene, magnesium powder and phosphorus chloride in a solvent to obtain chlorobis(2,6-dimethoxyphenyl)phosphine. In the present invention, the solvent is preferably toluene, tetrahydrofuran, ether and methyl tert-butyl ether, and more preferably toluene, tetrahydrofuran, ether and methyl tert-butyl ether. The present invention has no special restrictions on the sources of the 2-bromo-1,3-dimethoxybenzene, magnesium powder, phosphorus chloride and solvent, and commercially available products familiar to those skilled in the art can be used. The reaction is carried out under anhydrous and oxygen-free conditions; the molar ratio of the 2-bromo-1,3-dimethoxybenzene, magnesium powder and phosphorus chloride is 2:2.2 to 2.5:1, and more preferably 2:2.3 to 2.4:1. In one embodiment provided by the present invention, chlorobis(2,6-dimethoxyphenyl)phosphine can be synthesized specifically according to the following steps:

[0018] a1) mixing magnesium powder and solvent to obtain a mixed solution;

[0019] a2) controlling the temperature to 30° C. to 60° C., adding 2-bromo-1,3-dimethoxybenzene dropwise to the mixed solution obtained in step a1), and reacting for 2 h to 4 h after the addition is complete to obtain a reaction solution;

[0020] a3) controlling the temperature to be 0°C to 25°C, adding phosphorus chloride dropwise to the reaction solution obtained in step a2) for 0.5h to 1h, and after the addition is complete, raising the temperature to 30°C to 60°C and continuing the reaction for more than 4h to obtain chlorobis(2,6-dimethoxyphenyl)phosphine;

[0021] In the steps of synthesizing N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-alkyl-P,P-diphenylphosphamide provided in the above embodiment of the present invention, in step a2), after the dropwise addition is completed, the stirring is preferably maintained at the above temperature for 2h-4h, specifically 2h, 3h or 4h; in step a3), after the dropwise addition is completed, the stirring is preferably maintained at the above temperature for more than 4h, specifically 4h, 5h or 6h; after the insulation reaction is completed, the temperature is preferably raised to 30°C to 60°C to continue the reaction until the reaction is complete, specifically 30°C, 40°C, 45°C, 50°C or 60°C.

[0022] The preparation of the above chlorobis(2,6-dimethoxyphenyl)phosphine is achieved by a one-step process.

[0023] In the present invention, after the tracking detection reaction is completed, it is directly used in the next reaction without post-treatment:

[0024] After obtaining the chlorobis(2,6-dimethoxyphenyl)phosphine, the present invention reacts the obtained chlorobis(2,6-dimethoxyphenyl)phosphine with an alkylamine to obtain 1,1-bis(2,6-dimethoxyphenyl)-N-alkylphosphineamine. In the present invention, the solvent is preferably one or more of dichloromethane, tetrahydrofuran, toluene and xylene, more preferably dichloromethane, tetrahydrofuran, toluene or xylene. The alkylamine is methylamine, ethylamine, benylamine, propylamine, isopropylamine, n-butylamine, tert-butylamine, n-pentylamine, isopentylamine, neopentylamine, n-hexylamine or cyclohexylamine. The present invention has no special restrictions on the sources of the solvent and the alkylamine, and commercially available products well known to those skilled in the art can be used.

[0025] In the present invention, the reaction is carried out in the presence of a tertiary amine; the tertiary amine preferably includes triethylamine and / or tri-n-butylamine, more preferably triethylamine or tri-n-butylamine. The present invention has no particular limitation on the source of the tertiary amine, and commercially available products known to those skilled in the art can be used.

[0026] In the present invention, the molar ratio of chlorobis(2,6-dimethoxyphenyl)phosphine, tertiary amine and alkylamine is 1:1-2:1-1.5.

[0027] On this basis, the step b) is preferably specifically as follows:

[0028] b1) mixing the alkylamine, the tertiary amine and the solvent to obtain an alkylamine mixed solution;

[0029] b2) controlling the temperature to be between 0°C and 25°C, dripping the reaction solution of chlorobis(2,6-dimethoxyphenyl)phosphine obtained in step a3) into the alkylamine mixture, and after the dripping is completed, heating to 30°C to 60°C and continuing the reaction for more than 8 hours to obtain 1,1-bis(2,6-dimethoxyphenyl)-N-alkylphosphineamine;

[0030] In the steps of synthesizing 1,1-bis(2,6-dimethoxyphenyl)-N-alkylphosphine provided in the above embodiment of the present invention, in step b2), after the dropwise addition is completed, the stirring is preferably maintained at the above temperature for more than 8 hours, specifically 8 hours, 10 hours or 12 hours; after the insulation reaction is completed, the temperature is preferably raised to 30°C to 60°C and the reaction is continued until the reaction is complete, specifically 30°C, 40°C, 45°C, 50°C or 60°C.

[0031] In the present invention, after the tracking detection reaction is complete, it is preferred that the following steps are further included:

[0032] The mixture was extracted with dichloromethane and water for two to three times, dried over anhydrous sodium sulfate, and distilled and recrystallized under reduced pressure to obtain 1,1-bis(2,6-dimethoxyphenyl)-N-alkylphosphineamine.

[0033] After obtaining the 1,1-bis(2,6-dimethoxyphenyl)-N-alkylphosphinamide, the present invention reacts the obtained 1,1-bis(2,6-dimethoxyphenyl)-N-alkylphosphinamide with diphenylphosphinyl chloride to obtain a polyketone ligand N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-alkyl-P,P-diphenylphosphinamide.

[0034] In the present invention, the reaction is preferably carried out in the presence of a tertiary amine, and the solvent is preferably one or more of dichloromethane, tetrahydrofuran and toluene, more preferably one or more of dichloromethane, tetrahydrofuran and toluene.

[0035] In the present invention, there is no particular limitation on the sources of the tertiary amine, solvent and diphenylphosphinyl chloride, and commercially available products known to those skilled in the art may be used.

[0036] In the present invention, the molar ratio of the 1,1-bis(2,6-dimethoxyphenyl)-N-alkylphosphine amine, the tertiary amine and the diphenylphosphinyl chloride is 1:2.5-3.5:1-1.5.

[0037] On this basis, the step c) is preferably specifically as follows:

[0038] c1) mixing 1,1-bis(2,6-dimethoxyphenyl)-N-alkylphosphine amine, a tertiary amine and a solvent to obtain a 1,1-bis(2,6-dimethoxyphenyl)-N-alkylphosphine amine mixed solution;

[0039] c2) controlling the temperature to be 0°C to 25°C, adding diphenylphosphinyl chloride dropwise to the reaction solution obtained in step c1), and after the addition is complete, raising the temperature to 40°C to 60°C and continuing the reaction for more than 12 hours to obtain N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-alkyl-P,P-diphenylphosphinamide.

[0040] In the steps of synthesizing N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-alkyl-P,P-diphenylphosphamide provided in the above embodiment of the present invention, in step c2), after the dropwise addition is completed, it is preferably stirred at the above temperature for more than 12 hours, specifically 12 hours, 14 hours or 16 hours; after the insulation reaction is completed, it is preferably heated to 40°C to 60°C and continued to react until the reaction is complete, specifically 40°C, 45°C, 50°C or 60°C.

[0041] In the present invention, tracking the reaction progress until the reaction is complete preferably further comprises:

[0042] The product was extracted with dichloromethane and water for two to three times, dried over anhydrous sodium sulfate, and recrystallized by distillation under reduced pressure to obtain the target ligand.

[0043] Beneficial effects of the present invention: The present invention uses 2-bromo-1,3-dimethoxybenzene as a raw material, and first reacts with phosphorus chloride in a solvent to obtain chlorobis(2,6-dimethoxyphenyl)phosphine. Then react with alkylamine to obtain 1,1-bis(2,6-dimethoxyphenyl)-N-alkylphosphinamide. Finally, react with diphenylphosphinyl chloride to obtain a polyketone ligand N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-alkyl-P,P-diphenylphosphinamide. The reaction route and post-treatment process of the method are simple, the raw materials are cheap and easy to obtain, the product yield is high, and the quality is good. Experimental results show that when the polyketone ligand N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-alkyl-P,P-diphenylphosphinamide is synthesized by the method provided by the present invention, the product purity is greater than 98% and the yield is greater than 95%. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 The nuclear magnetic resonance phosphorus spectrum of N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-ethyl-P,P-diphenylphosphamide provided in Example 1 of the present invention;

[0045] Figure 2 This is the hydrogen nuclear magnetic resonance spectrum of N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-ethyl-P,P-diphenylphosphamide provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0046] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings and technical solutions.

[0047] Example 1

[0048] (1) Preparation of chlorobis(2,6-dimethoxyphenyl)phosphine

[0049] Under anhydrous and oxygen-free conditions, add 1.46g magnesium powder to 30mL tetrahydrofuran, raise the temperature to 30°C, and start to drop 1.09g of 2-bromo-1,3-dimethoxybenzene. After the addition is complete, control the temperature and stir for 2h. Cool down to 0°C, and start to control the temperature and drop 0.34g of phosphorus chloride. After the addition is complete, raise the temperature to 30°C, control the temperature and stir for 4h. No post-treatment is required, and the reaction solution is directly used for the next step.

[0050] (2) Preparation of 1,1-bis(2,6-dimethoxyphenyl)-N-ethylphosphine

[0051] Under anhydrous and oxygen-free conditions, add 1.4 mL of triethylamine and 20 mL of tetrahydrofuran to a 100 mL reaction kettle, and fill the kettle with 0.27 g of ethylamine gas through a mass flow meter. Under 25°C, add the reaction solution obtained in (1) dropwise at a controlled temperature, and react at room temperature for 4 hours after the addition is complete. Extract with dichloromethane and water two to three times, dry over anhydrous sodium sulfate, and distill and recrystallize under reduced pressure to obtain 1.6 g of 1,1-bis(2,6-dimethoxyphenyl)-N-ethylphosphinamine with a purity of 98.35% and a yield of 91.43%.

[0052] (3) Preparation of N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-ethyl-P,P-diphenylphosphinamide:

[0053] 1.6 g of 1,1-bis(2,6-dimethoxyphenyl)-N-ethylphosphinamide and 1.27 mL of triethylamine were added to 30 mL of tetrahydrofuran, cooled to 0°C, and 1.3 g of diphenylphosphinyl chloride was added dropwise under temperature control. After the addition was completed, the temperature was raised to 40°C for reaction for 12 hours. After the reaction was completed, dichloromethane and water were extracted two to three times, dried over anhydrous sodium sulfate, and distilled and recrystallized under reduced pressure to obtain 2.4 g of the target ligand N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-ethyl-P,P-diphenylphosphinamide, with a purity of 98.25% and a yield of 95.23%.

[0054] The structure of the prepared N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-ethyl-P,P-diphenylphosphinamide was characterized. Figure 1 , Figure 2 As shown, Figure 1 is the nuclear magnetic resonance phosphorus spectrum of N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-ethyl-P,P-diphenylphosphinamidoalkane provided in Example 1 of the present invention, Figure 2 This is the hydrogen nuclear magnetic resonance spectrum of N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-ethyl-P,P-diphenylphosphinamidoalkane provided in Example 1 of the present invention.

[0055] Example 2

[0056] A method for synthesizing a polyketone ligand N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-benzyl-P,P-diphenylphosphamide, the synthetic route is similar to that of Example 1, except that ethylamine is replaced by benzylamine:

[0057] (1) Preparation of chlorobis(2,6-dimethoxyphenyl)phosphine

[0058] Under anhydrous and oxygen-free conditions, add 1.46g magnesium powder to 30mL tetrahydrofuran, raise the temperature to 30°C, and start to drop 1.09g of 2-bromo-1,3-dimethoxybenzene. After the addition is complete, control the temperature and stir for 2h. Cool down to 0°C, and start to control the temperature and drop 0.34g of phosphorus chloride. After the addition is complete, raise the temperature to 30°C, control the temperature and stir for 4h. No post-treatment is required, and the reaction solution is directly used for the next step.

[0059] (2) Preparation of 1,1-bis(2,6-dimethoxyphenyl)-N-benzylphosphine

[0060] Under anhydrous and oxygen-free conditions, add 0.64 g of benzylamine, 1.4 mL of triethylamine and 20 mL of tetrahydrofuran to a 100 mL three-necked flask. Add the reaction solution obtained in (1) dropwise at 25°C, and react at room temperature for 4 hours after the addition is complete. Extract with dichloromethane and water two to three times, dry over anhydrous sodium sulfate, and distill and recrystallize under reduced pressure to obtain 1.9 g of 1,1-bis(2,6-dimethoxyphenyl)-N-benzylphosphineamine with a purity of 98.35% and a yield of 92.23%.

[0061] (3) Preparation of N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-benzyl-P,P-diphenylphosphinamide:

[0062] 1.9 g of 1,1-bis(2,6-dimethoxyphenyl)-N-benzylphosphine and 1.27 mL of triethylamine were added to 30 mL of tetrahydrofuran, cooled to 0°C, and 1.3 g of diphenylphosphinyl chloride was added dropwise under temperature control. After the addition was completed, the temperature was raised to 40°C for reaction for 12 hours. After the reaction was completed, dichloromethane and water were extracted two to three times, dried over anhydrous sodium sulfate, and distilled and recrystallized under reduced pressure to obtain 2.7 g of the target ligand N-(bis(2,6-dimethoxyphenyl)phosphine)-N-benzyl-P,P-diphenylphosphine, with a purity of 98.25% and a yield of 95.74%.

[0063] Example 3

[0064] A method for synthesizing a polyketone ligand N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-n-butyl-P,P-diphenylphosphamide, the synthetic route is similar to that of Example 1, except that ethylamine is replaced with n-butylamine:

[0065] (1) Preparation of chlorobis(2,6-dimethoxyphenyl)phosphine

[0066] Under anhydrous and oxygen-free conditions, add 1.46g magnesium powder to 30mL tetrahydrofuran, raise the temperature to 30°C, and start to drop 1.09g of 2-bromo-1,3-dimethoxybenzene. After the addition is complete, control the temperature and stir for 2h. Cool down to 0°C, and start to control the temperature and drop 0.34g of phosphorus chloride. After the addition is complete, raise the temperature to 30°C, control the temperature and stir for 4h. No post-treatment is required, and the reaction solution is directly used for the next step.

[0067] (2) Preparation of 1,1-bis(2,6-dimethoxyphenyl)-N-butylphosphineamine

[0068] Under anhydrous and oxygen-free conditions, add 0.44 g of n-butylamine, 1.4 mL of triethylamine and 20 mL of tetrahydrofuran to a 100 mL three-necked flask. Add the reaction solution obtained in (1) dropwise at 25°C, and react at room temperature for 4 hours after the addition is complete. Extract with dichloromethane and water two to three times, dry over anhydrous sodium sulfate, and distill and recrystallize under reduced pressure to obtain 1.8 g of 1,1-bis(2,6-dimethoxyphenyl)-N-n-butylphosphinamine with a purity of 98.35% and a yield of 95.23%.

[0069] (3) Preparation of N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-n-butyl-P,P-diphenylphosphinamide:

[0070] 1.8 g of 1,1-bis(2,6-dimethoxyphenyl)-N-n-butylphosphinamide and 1.27 mL of triethylamine were added to 30 mL of tetrahydrofuran, cooled to 0°C, and 1.35 g of diphenylphosphinyl chloride was added dropwise under temperature control. After the addition was completed, the temperature was raised to 40°C for reaction for 12 hours. After the reaction was completed, dichloromethane and water were extracted two to three times, dried over anhydrous sodium sulfate, and distilled and recrystallized under reduced pressure to obtain 2.6 g of the target ligand N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-n-butyl-P,P-diphenylphosphinamide, with a purity of 98.25% and a yield of 94.55%.

[0071] Example 4

[0072] (1) Preparation of chlorobis(2,6-dimethoxyphenyl)phosphine

[0073] Under anhydrous and oxygen-free conditions, add 1.46g magnesium powder to 30mL tetrahydrofuran, raise the temperature to 40°C, and start to drop 1.09g of 2-bromo-1,3-dimethoxybenzene. After the addition is complete, control the temperature and stir for 2h. Cool down to 0°C, and start to control the temperature and drop 0.34g of phosphorus chloride. After the addition is complete, raise the temperature to 40°C, control the temperature and stir for 4h. No post-treatment is required, and the reaction solution is directly used for the next step.

[0074] (2) Preparation of 1,1-bis(2,6-dimethoxyphenyl)-N-ethylphosphine

[0075] Under anhydrous and oxygen-free conditions, add 1.4 mL of triethylamine and 20 mL of tetrahydrofuran to a 100 mL reaction kettle, and fill the kettle with 0.27 g of ethylamine gas through a mass flow meter. Under 25°C, add the reaction solution obtained in (1) dropwise, and after the addition is complete, heat to 40°C and react for 4 hours. Extract with dichloromethane and water two to three times, dry over anhydrous sodium sulfate, and distill and recrystallize under reduced pressure to obtain 1.6 g of 1,1-bis(2,6-dimethoxyphenyl)-N-ethylphosphinamine with a purity of 98.35% and a yield of 91.43%.

[0076] (3) Preparation of N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-ethyl-P,P-diphenylphosphinamide:

[0077] 1.6 g of 1,1-bis(2,6-dimethoxyphenyl)-N-ethylphosphinamide and 1.27 mL of triethylamine were added to 30 mL of tetrahydrofuran, cooled to 0°C, and 1.3 g of diphenylphosphinyl chloride was added dropwise under temperature control. After the addition was completed, the temperature was raised to 50°C for reaction for 12 hours. After the reaction was completed, dichloromethane and water were extracted two to three times, dried over anhydrous sodium sulfate, and distilled and recrystallized under reduced pressure to obtain 2.4 g of the target ligand N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-ethyl-P,P-diphenylphosphinamide, with a purity of 98.25% and a yield of 96%.

[0078] Example 5

[0079] (1) Preparation of chlorobis(2,6-dimethoxyphenyl)phosphine

[0080] Under anhydrous and oxygen-free conditions, add 1.46g magnesium powder to 30mL tetrahydrofuran, raise the temperature to 45°C, and start to drop 1.09g of 2-bromo-1,3-dimethoxybenzene. After the addition is complete, control the temperature and stir for 2h. Cool down to 0°C, and start to control the temperature and drop 0.34g of phosphorus chloride. After the addition is complete, raise the temperature to 45°C, control the temperature and stir for 4h. No post-treatment is required, and the reaction solution is directly used for the next step.

[0081] (2) Preparation of 1,1-bis(2,6-dimethoxyphenyl)-N-ethylphosphine

[0082] Under anhydrous and oxygen-free conditions, add 1.4 mL of triethylamine and 20 mL of tetrahydrofuran to a 100 mL reaction kettle, and fill the kettle with 0.27 g of ethylamine gas through a mass flow meter. Under 25°C, add the reaction solution obtained in (1) dropwise, and after the addition is complete, heat to 45°C and react for 4 hours. Extract with dichloromethane and water two to three times, dry over anhydrous sodium sulfate, and distill and recrystallize under reduced pressure to obtain 1.6 g of 1,1-bis(2,6-dimethoxyphenyl)-N-ethylphosphinamine with a purity of 98.35% and a yield of 91.43%.

[0083] (3) Preparation of N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-ethyl-P,P-diphenylphosphinamide:

[0084] 1.6 g of 1,1-bis(2,6-dimethoxyphenyl)-N-ethylphosphinamide and 1.27 mL of triethylamine were added to 30 mL of tetrahydrofuran, cooled to 0°C, and 1.3 g of diphenylphosphinyl chloride was added dropwise under temperature control. After the addition was completed, the temperature was raised to 55°C for reaction for 12 hours. After the reaction was completed, dichloromethane and water were extracted two to three times, dried over anhydrous sodium sulfate, and distilled and recrystallized under reduced pressure to obtain 2.4 g of the target ligand N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-ethyl-P,P-diphenylphosphinamide, with a purity of 98.25% and a yield of 96%.

[0085] Example 6

[0086] (1) Preparation of chlorobis(2,6-dimethoxyphenyl)phosphine

[0087] Under anhydrous and oxygen-free conditions, add 1.46g of magnesium powder to 30mL of tetrahydrofuran, raise the temperature to 30°C, and start to drop 1.09g of 2-bromo-1,3-dimethoxybenzene. After the addition is complete, control the temperature and stir for 3h. Cool down to 0°C, and start to control the temperature and drop 0.34g of phosphorus chloride. After the addition is complete, raise the temperature to 30°C, control the temperature and stir for 5h. No post-treatment is required, and the reaction solution is directly used for the next step.

[0088] (2) Preparation of 1,1-bis(2,6-dimethoxyphenyl)-N-ethylphosphine

[0089] Under anhydrous and oxygen-free conditions, add 1.4 mL of triethylamine and 20 mL of tetrahydrofuran to a 100 mL reaction kettle, and fill the kettle with 0.27 g of ethylamine gas through a mass flow meter. Add the reaction solution obtained in (1) dropwise at 25°C, and react at room temperature for 5 hours after the addition is complete. Extract with dichloromethane and water two to three times, dry with anhydrous sodium sulfate, and distill and recrystallize under reduced pressure to obtain 1.6 g of 1,1-bis(2,6-dimethoxyphenyl)-N-ethylphosphinamine with a purity of 98.35% and a yield of 91.43%.

[0090] (3) Preparation of N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-ethyl-P,P-diphenylphosphinamide:

[0091] 1.6 g of 1,1-bis(2,6-dimethoxyphenyl)-N-ethylphosphinamide and 1.27 mL of triethylamine were added to 30 mL of tetrahydrofuran, cooled to 0°C, and 1.3 g of diphenylphosphinyl chloride was added dropwise under temperature control. After the addition was completed, the temperature was raised to 40°C for reaction for 16 hours. After the reaction was completed, dichloromethane and water were extracted two to three times, dried over anhydrous sodium sulfate, and distilled and recrystallized under reduced pressure to obtain 2.4 g of the target ligand N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-ethyl-P,P-diphenylphosphinamide, with a purity of 98.25% and a yield of 96%.

[0092] Example 7

[0093] (1) Preparation of chlorobis(2,6-dimethoxyphenyl)phosphine

[0094] Under anhydrous and oxygen-free conditions, add 1.46g magnesium powder to 30mL toluene, raise the temperature to 30°C, and start to drop 1.09g of 2-bromo-1,3-dimethoxybenzene. After the addition is complete, control the temperature and stir for 4h. Cool down to 0°C, and start to control the temperature and drop 0.34g of phosphorus chloride. After the addition is complete, raise the temperature to 30°C, control the temperature and stir for 6h. No post-treatment is required, and the reaction solution is directly used for the next step.

[0095] (2) Preparation of 1,1-bis(2,6-dimethoxyphenyl)-N-ethylphosphine

[0096] Under anhydrous and oxygen-free conditions, add 1.4 mL of triethylamine and 20 mL of toluene to a 100 mL reaction kettle, and fill the kettle with 0.27 g of ethylamine gas through a mass flow meter. Add the reaction solution obtained in (1) dropwise at 25°C, and react at room temperature for 6 hours after the addition is complete. Extract with ethyl acetate and water two to three times, dry with anhydrous sodium sulfate, and distill and recrystallize under reduced pressure to obtain 1.6 g of 1,1-bis(2,6-dimethoxyphenyl)-N-ethylphosphinamine with a purity of 98.17% and a yield of 91.43%.

[0097] (3) Preparation of N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-ethyl-P,P-diphenylphosphinamide:

[0098] 1.6 g of 1,1-bis(2,6-dimethoxyphenyl)-N-ethylphosphinamide and 1.27 mL of triethylamine were added to 30 mL of toluene, cooled to 0°C, and 1.3 g of diphenylphosphinyl chloride was added dropwise under temperature control. After the addition was completed, the temperature was raised to 40°C for reaction for 24 hours. After the reaction was completed, the mixture was extracted with ethyl acetate and water for two to three times, dried over anhydrous sodium sulfate, and recrystallized by distillation under reduced pressure to obtain 2.4 g of the target ligand N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-ethyl-P,P-diphenylphosphinamide, with a purity of 98.25% and a yield of 96%.

[0099] Example 8

[0100] (1) Preparation of chlorobis(2,6-dimethoxyphenyl)phosphine

[0101] Under anhydrous and oxygen-free conditions, add 1.46g of magnesium powder to 30mL of ether, raise the temperature to 30°C, and start to drop 1.09g of 2-bromo-1,3-dimethoxybenzene. After the addition is complete, control the temperature and stir for 2h. Cool down to 0°C, and start to control the temperature and drop 0.34g of phosphorus chloride. After the addition is complete, raise the temperature to 30°C, control the temperature and stir for 4h. No post-treatment is required, and the reaction solution is directly used for the next step.

[0102] (2) Preparation of 1,1-bis(2,6-dimethoxyphenyl)-N-ethylphosphine

[0103] Under anhydrous and oxygen-free conditions, add 1.4 mL of triethylamine and 20 mL of ether to a 100 mL reaction kettle, and fill the kettle with 0.27 g of ethylamine gas through a mass flow meter. Add the reaction solution obtained in (1) dropwise at 25°C, and react at room temperature for 4 hours after the addition is complete. Extract with ethyl acetate and water two to three times, dry with anhydrous sodium sulfate, and distill and recrystallize under reduced pressure to obtain 1.6 g of 1,1-bis(2,6-dimethoxyphenyl)-N-ethylphosphinamine with a purity of 98.26% and a yield of 91.43%.

[0104] (3) Preparation of N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-ethyl-P,P-diphenylphosphinamide:

[0105] 1.6 g of 1,1-bis(2,6-dimethoxyphenyl)-N-ethylphosphinamide and 1.27 mL of triethylamine were added to 30 mL of ether, cooled to 0°C, and 1.3 g of diphenylphosphinyl chloride was added dropwise under temperature control. After the addition was complete, the temperature was raised to 40°C for reaction for 12 hours. After the reaction was completed, the mixture was extracted with ethyl acetate and water for two to three times, dried over anhydrous sodium sulfate, and recrystallized by vacuum distillation to obtain 2.4 g of the target ligand N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-ethyl-P,P-diphenylphosphinamide, with a purity of 98.25% and a yield of 95.87%.

[0106] Example 9

[0107] (1) Preparation of chlorobis(2,6-dimethoxyphenyl)phosphine

[0108] Under anhydrous and oxygen-free conditions, add 14.6g of magnesium powder to 300mL of tetrahydrofuran, raise the temperature to 30°C, and start to drop 10.9g of 2-bromo-1,3-dimethoxybenzene. After the addition is complete, control the temperature and stir for 2h. Cool down to 0°C, and start to control the temperature and drop 3.4g of phosphorus chloride. After the addition is complete, raise the temperature to 30°C, control the temperature and stir for 4h. No post-treatment is required, and the reaction solution is directly used for the next step.

[0109] (2) Preparation of 1,1-bis(2,6-dimethoxyphenyl)-N-ethylphosphine

[0110] Under anhydrous and oxygen-free conditions, add 14 mL of triethylamine and 200 mL of tetrahydrofuran to a 1 L reaction kettle, and fill the kettle with 2.7 g of ethylamine gas through a mass flow meter. Add the reaction solution obtained in (1) dropwise at 25°C, and react at room temperature for 4 hours after the addition is complete. Extract with ethyl acetate and water two to three times, dry over anhydrous sodium sulfate, and distill and recrystallize under reduced pressure to obtain 16 g of 1,1-bis(2,6-dimethoxyphenyl)-N-ethylphosphinamine with a purity of 97.34% and a yield of 91.13%.

[0111] (3) Preparation of N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-ethyl-P,P-diphenylphosphinamide:

[0112] 16g of 1,1-bis(2,6-dimethoxyphenyl)-N-ethylphosphinamide and 12.7mL of triethylamine were added to 300mL of tetrahydrofuran, cooled to 0°C, and 13g of diphenylphosphinyl chloride was added dropwise under temperature control. After the addition was completed, the temperature was raised to 40°C and reacted for 12h. After the reaction was completed, the mixture was extracted with ethyl acetate and water for two to three times, dried over anhydrous sodium sulfate, and recrystallized by distillation under reduced pressure to obtain 24g of the target ligand N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-ethyl-P,P-diphenylphosphinamide, with a purity of 98.25% and a yield of 95.96%.

[0113] Example 10

[0114] (1) Preparation of chlorobis(2,6-dimethoxyphenyl)phosphine

[0115] Under anhydrous and oxygen-free conditions, add 58.4g of magnesium powder to 1000mL of tetrahydrofuran, raise the temperature to 30°C, and start to drop 43.6g of 2-bromo-1,3-dimethoxybenzene. After the addition is complete, control the temperature and stir for 2h. Cool down to 0°C, and start to control the temperature and drop 13.6g of phosphorus chloride. After the addition is complete, raise the temperature to 30°C, control the temperature and stir for 4h. No post-treatment is required, and the reaction solution is directly used for the next step.

[0116] (2) Preparation of 1,1-bis(2,6-dimethoxyphenyl)-N-ethylphosphine

[0117] Under anhydrous and oxygen-free conditions, add 56 mL of triethylamine and 800 mL of tetrahydrofuran to a 3000 mL reaction kettle, and fill the kettle with 10.8 g of ethylamine gas through a mass flow meter. Add the reaction solution obtained in (1) dropwise at 25°C, and react at room temperature for 4 hours after the addition is complete. Extract with dichloromethane and water two to three times, dry over anhydrous sodium sulfate, and distill and recrystallize under reduced pressure to obtain 64 g of 1,1-bis(2,6-dimethoxyphenyl)-N-ethylphosphineamine with a purity of 98.35% and a yield of 91.43%.

[0118] (3) Preparation of N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-ethyl-P,P-diphenylphosphinamide:

[0119] 64g of 1,1-bis(2,6-dimethoxyphenyl)-N-ethylphosphinamide and 50.8mL of triethylamine were added to 1000mL of tetrahydrofuran, cooled to 0°C, and 52g of diphenylphosphinyl chloride was added dropwise under temperature control. After the addition was completed, the temperature was raised to 40°C and reacted for 12h. After the reaction was completed, dichloromethane and water were extracted two to three times, dried over anhydrous sodium sulfate, and distilled and recrystallized under reduced pressure to obtain 96g of the target ligand N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-ethyl-P,P-diphenylphosphinamide, with a purity of 98.25% and a yield of 95.23%.

[0120] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for synthesizing a polyketone ligand, characterized in that: The polyketone ligand is N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-alkyl-P,P-diphenylphosphinamide, and has the following structure: Wherein, R is methyl, ethyl, benzyl, propyl, isopropyl, n-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, cyclohexyl; The synthetic route is as follows: The specific steps are as follows: a) reacting 2-bromo-1,3-dimethoxybenzene, magnesium powder and phosphorus chloride in a solvent to obtain chlorobis(2,6-dimethoxyphenyl)phosphine; b) reacting the chlorobis(2,6-dimethoxyphenyl)phosphine obtained in step a) with an alkylamine to obtain 1,1-bis(2,6-dimethoxyphenyl)-N-alkylphosphineamine; c) reacting the 1,1-bis(2,6-dimethoxyphenyl)-N-alkylphosphinamide obtained in step b) with diphenylphosphinyl chloride to obtain a polyketone ligand N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-alkyl-P,P-diphenylphosphinamide.

2. The synthesis method according to claim 1, characterized in that In step a), The solvent is toluene, tetrahydrofuran, diethyl ether or methyl tert-butyl ether; The reaction is carried out under anhydrous and oxygen-free conditions; The molar ratio of the 2-bromo-1,3-dimethoxybenzene, magnesium powder and phosphorus chloride is 2:2.2 to 2.5:

1.

3. The synthesis method according to claim 1, characterized in that The specific steps of step a) are as follows: a1) mixing magnesium powder and solvent to obtain a mixed solution; a2) controlling the temperature to 30° C. to 60° C., adding 2-bromo-1,3-dimethoxybenzene dropwise to the mixed solution obtained in step a1), and reacting for 2 h to 4 h after the addition is complete to obtain a reaction solution; a3) controlling the temperature to be 0°C to 25°C, adding phosphorus chloride dropwise to the reaction solution obtained in step a2) for 0.5h to 1h, and after the addition is complete, raising the temperature to 30°C to 60°C and continuing the reaction for more than 4h to obtain chlorobis(2,6-dimethoxyphenyl)phosphine.

4. The synthesis method according to claim 1, characterized in that In step b), The solvent is one or a combination of two or more of dichloromethane, tetrahydrofuran, toluene and xylene; The alkylamine is methylamine, ethylamine, benzylic amine, propylamine, isopropylamine, n-butylamine, tert-butylamine, n-pentylamine, isopentylamine, neopentylamine, n-hexylamine or cyclohexylamine; The reaction is carried out in the presence of a tertiary amine; The tertiary amine is triethylamine and / or tri-n-butylamine; The molar ratio of the chlorobis(2,6-dimethoxyphenyl)phosphine, the tertiary amine and the alkylamine is 1:1-2:1-1.

5.

5. The synthesis method according to claim 1, characterized in that The specific steps of step b) are as follows: b1) mixing the alkylamine, the tertiary amine and the solvent to obtain an alkylamine mixed solution; b2) Controlling the temperature at 0°C to 25°C, dripping the reaction solution of chlorobis(2,6-dimethoxyphenyl)phosphine obtained in step a3) into the alkylamine mixture, and after the dripping is completed, heating to 30°C to 60°C and continuing the reaction for more than 8 hours to obtain 1,1-bis(2,6-dimethoxyphenyl)-N-alkylphosphineamine.

6. The synthesis method according to claim 5, characterized in that Step b2) further comprises: The mixture was extracted with dichloromethane and water for two to three times, dried over anhydrous sodium sulfate, and distilled and recrystallized under reduced pressure to obtain 1,1-bis(2,6-dimethoxyphenyl)-N-alkylphosphineamine.

7. The synthesis method according to claim 1, characterized in that In step c), The reaction is carried out in the presence of a tertiary amine; The solvent is one or a mixture of two or more of dichloromethane, tetrahydrofuran and toluene; The molar ratio of the 1,1-bis(2,6-dimethoxyphenyl)-N-alkylphosphine amine, the tertiary amine and the diphenylphosphinyl chloride is 1:2.5-3.5:1-1.

5.

8. The synthesis method according to claim 1, characterized in that The specific steps of step c) are as follows: c1) mixing 1,1-bis(2,6-dimethoxyphenyl)-N-alkylphosphine amine, a tertiary amine and a solvent to obtain a 1,1-bis(2,6-dimethoxyphenyl)-N-alkylphosphine amine mixed solution; c2) controlling the temperature to be 0°C to 25°C, adding diphenylphosphinyl chloride dropwise to the reaction solution obtained in step c1), and after the addition is complete, raising the temperature to 40°C to 60°C and continuing the reaction for more than 12 hours to obtain N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-alkyl-P,P-diphenylphosphinamide.

9. The synthesis method according to claim 1, characterized in that Step c2) further comprises: The mixture was extracted with dichloromethane and water for two to three times, dried over anhydrous sodium sulfate, and recrystallized by distillation under reduced pressure to obtain N-(bis(2,6-dimethoxyphenyl)phosphinoyl)-N-alkyl-P,P-diphenylphosphinamide.

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