Method for synthesizing adamantane phosphine through free radical phosphorization reaction

Abstract

The invention discloses a method for synthesizing adamantane phosphine through a free radical phosphorization reaction, and belongs to the technical field of organic phosphorus compound synthesis, and the method comprises the following steps: in an argon atmosphere, respectively adding adamantane, a free radical initiator, potassium phosphate and lithium carbonate into a reaction kettle, then adding a solvent, finally adding a phosphorus reagent, and carrying out a heating reaction; after the reaction is finished, filtering and spin-drying; and adding a saturated saline solution, extracting with ethyl acetate, collecting an organic phase, and collecting a target product in a recrystallization manner, thereby obtaining the target product. According to the method, adamantane which is cheap and easy to obtain is taken as a starting material, NHPI and AIBN are taken as free radical initiators, adamantane free radicals are formed by adamantane through hydrogen atom transfer, and the adamantane free radicals finally react with a phosphorus reagent to obtain adamantane phosphine. The method not only can overcome the limitation of the traditional synthesis method, but also can improve the economical efficiency and practicability of the reaction, and has important academic value and application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of the synthesis of organophosphorus compounds, and particularly relates to a method for synthesizing adamantylphosphine through a radical phosphination reaction. Background Art

[0002] Adamantylphosphine is a class of important organophosphorus compounds. Its unique structure enables it to have a wide range of applications in the fields of catalysis, drug synthesis, and materials science. Due to its excellent stability and reactivity, adamantylphosphine is often used as a catalyst and ligand. However, traditional methods for synthesizing adamantylphosphine mostly employ phosphination reactions or nucleophilic substitution reactions, which require multiple steps and relatively harsh reaction conditions. These methods not only have complex reaction steps but also often produce by-products, leading to a cumbersome purification process. In addition, many existing methods also rely on expensive or difficult-to-obtain raw materials, restricting their application in large-scale synthesis. The relevant reports are as follows:

[0003] (1) Literature reports on triscadamantylphosphine:

[0004]

[0005] (2) Literature reports on aryldiscadamantylphosphine:

[0006]

[0007] (3) Literature reports on n-butyldiscadamantylphosphine:

[0008]

[0009] In the existing literature reports on the above three types of adamantylphosphine, the reactions all suffer from the problems of expensive substrates, cumbersome preparation, relatively harsh reaction conditions, and low reaction efficiency, and are not suitable for large-scale industrial production.

[0010] In recent years, radical chemistry has gradually become an important means for synthesizing novel organic compounds. Radical reactions have the advantages of being fast, efficient, and highly selective, and can achieve various chemical transformations under mild conditions. However, current research on synthesizing adamantylphosphine using radical reactions is still relatively scarce, and no systematic method has been formed.

[0011] Therefore, developing a new synthesis method to efficiently synthesize adamantylphosphine through a radical phosphination reaction can not only overcome the limitations of traditional synthesis methods but also improve the economy and practicality of the reaction, and has important academic value and application prospects. Summary of the Invention

[0012] The present invention provides a method for synthesizing adamantylphosphine through a radical phosphination reaction, which solves the deficiencies in the prior art and improves the synthesis efficiency and product quality.

[0013] To solve the above technical problems, the technical solution of the present invention is as follows:

[0014] A method for synthesizing adamantylphosphine through a radical phosphination reaction, comprising the following steps:

[0015] (1) Under an argon atmosphere, add adamantane, a radical initiator, potassium phosphate, and lithium carbonate into a reaction kettle respectively, then add a solvent, and finally add a phosphorus reagent, and heat for reaction;

[0016] (2) After the reaction is completed, filter and rotary evaporate to dryness;

[0017] (3) Add saturated brine, then extract with ethyl acetate. After collecting the organic phase, collect the target product by recrystallization to obtain the product.

[0018] Wherein, the radical initiator is AIBN and / or NHPI.

[0019] Wherein, the solvent is acetonitrile, ethyl acetate or dichloroethane.

[0020] Wherein, the phosphorus reagent is triethyl phosphite, diethyl phenylphosphite or diethyl tert-butylphosphite.

[0021] Wherein, in step (1), the temperature for the heating reaction is 50-70 °C, and the reaction time is 20-30 h.

[0022] Wherein, the molar ratio of adamantane to the radical initiator is 1:1-1.5, the molar ratio of adamantane to potassium phosphate is 1:1-1.5, the molar ratio of adamantane to lithium carbonate is 1:0.5-1, and the molar ratio of adamantane to the phosphorus reagent is 1:0.4-0.5.

[0023] Through exploration of reaction substrates and screening of conditions, the present invention has successfully realized a method for efficiently synthesizing adamantylphosphine through a radical phosphination reaction. This method starts from cheap and easily available adamantane, uses NHPI (N-hydroxyphthalimide) and AIBN (azobisisobutyronitrile) as radical initiators. Adamantane forms an adamantyl radical through hydrogen atom transfer (HAT), and finally reacts with the phosphorus reagent to obtain adamantylphosphine. In the reaction, potassium phosphate and lithium carbonate jointly regulate the acidity and alkalinity of the reaction environment, promote the generation of free radicals, and inhibit the occurrence of side reactions.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention provides a new synthesis method for efficiently synthesizing adamantylphosphine through a radical phosphination reaction, which can not only overcome the limitations of traditional synthesis methods, but also improve the economy and practicability of the reaction, and has important academic value and application prospects. Detailed implementation manners

[0026] The technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0027] Example 1

[0028] This example provides a method for synthesizing adamantylphosphine through a radical phosphination reaction. The reaction equation of this method is as follows:

[0029]

[0030] It includes the following steps:

[0031] (1) Under an argon atmosphere, add adamantane (3.5 mol, 3.5 equiv), AIBN (4.0 mol, 4.0 equiv), NHPI (0.3 mol, 0.3 equiv), potassium phosphate (4.0 mol, 4.0 equiv), and lithium carbonate (3 mol, 3 equiv) into a 2 L reaction kettle respectively, then add acetonitrile (1000 mL), and finally add a phosphorus reagent (1.0 mol, 1.0 equiv), and react in an oil bath at 60 °C for 24 h.

[0032] (2) After the reaction is completed, filter and rotary evaporate to dryness.

[0033] (3) Add saturated brine, and extract three times with ethyl acetate (300 mL × 3). After collecting the organic phase, collect the target product by recrystallization (379.9 g, 87% yield). 1 H NMR (400 MHz, CD2Cl2) δ 2.13 (br, 18H), 1.84 (br, 9H), 1.74 - 1.58 (m, 18H). 13 C NMR (101 MHz, CD2Cl2): δ 42.7 (br), 41.1 (d, J = 34.3 Hz), 37.0, 29.5 (d, J = 7.2 Hz).

[0034] Example 2

[0035] This example provides a method for synthesizing adamantylphosphine through a radical phosphination reaction. The reaction equation of this method is as follows:

[0036]

[0037] It includes the following steps:

[0038] (1) Under an argon atmosphere, adamantane (3.5 mol, 3.5 equiv), AIBN (3.0 mol, 3.0 equiv), NHPI (0.5 mol, 0.5 equiv), potassium phosphate (3.5 mol, 3.5 equiv), and lithium carbonate (1.75 mol, 1.75 equiv) were added to a 2 L reaction kettle respectively. Then ethyl acetate (1000 mL) was added, and finally a phosphorus reagent (0.35 mol, 0.35 equiv) was added. The reaction was carried out in an oil bath at 70 °C for 20 h.

[0039] (2) After the reaction was completed, filtration was carried out and the solvent was evaporated by rotary evaporation.

[0040] (3) Saturated brine was added, and then extraction with ethyl acetate was carried out three times (300 mL × 3). After the organic phase was collected, the target product was collected by recrystallization (355.8 g, 94% yield). 1 1H NMR (400 MHz, CDCl3): δ 7.65 - 7.45 (m, 2H), 7.30 - 7.20 (m, 3H), 2.10 - 1.55 (m, 30H); 13 13C NMR (101 MHz, CDCl3): δ 134.5, 130.9, 128.8, 127.3, 42.4, 36.6, 34.8, 28.9.

[0041] Example 3

[0042] This example provides a method for synthesizing adamantylphosphine through a radical phosphination reaction. The reaction equation of this method is as follows:

[0043]

[0044] It includes the following steps:

[0045] (1) Under an argon atmosphere, adamantane (3.5 mol, 3.5 equiv), AIBN (6.0 mol, 6.0 equiv), NHPI (1 mol, 1.0 equiv), potassium phosphate (5.25 mol, 5.25 equiv), and lithium carbonate (3.5 mol, 3.5 equiv) were added to a 2 L reaction kettle respectively. Then dichloroethane (1000 mL) was added, and finally a phosphorus reagent (1.75 mol, 1.75 equiv) was added. The reaction was carried out in an oil bath at 50 °C for 30 h.

[0046] (2) After the reaction was completed, filtration was carried out and the solvent was evaporated by rotary evaporation.

[0047] (3) Add saturated brine, and then extract three times with ethyl acetate (300 mL×3). After collecting the organic phase, collect the target product by recrystallization (304.8 g, 85% yield). 1 1H NMR (400 MHz, CDCl3): δ 0.96 (t, 3H, J = 7.3 Hz), 1.35–2.03 (m, 36H). 13 13C NMR (101 MHz, CDCl3): δ 41.3, 37.4, 36.1, 33.9, 29.1, 24.9, 17.1, 14.3.

[0048] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for synthesizing adamantylphosphine through a free radical phosphination reaction, characterized in that It includes the following steps: (1) Under an argon atmosphere, add adamantane, a radical initiator, potassium phosphate, and lithium carbonate into a reaction kettle respectively, then add a solvent, and finally add a phosphorus reagent, and heat for reaction; (2) After the reaction is completed, filter and rotary evaporate to dryness; (3) Add saturated brine, extract with ethyl acetate, after collecting the organic phase, collect the target product by recrystallization to obtain it.

2. The method for synthesizing adamantylphosphine through a radical phosphination reaction according to claim 1, wherein: The radical initiator is AIBN and / or NHPI.

3. A method for synthesizing adamantylphosphine through a radical phosphination reaction according to claim 1, characterized in that: The solvent is acetonitrile, ethyl acetate or dichloroethane.

4. A method for synthesizing adamantylphosphine through a radical phosphination reaction according to claim 1, characterized in that: The phosphorus reagent is triethyl phosphite, diethyl phenylphosphite or diethyl tert-butylphosphite.

5. A method for synthesizing adamantylphosphine through a free radical phosphination reaction according to claim 1, characterized in that: In step (1), the temperature for heating the reaction is 50-70 °C, and the reaction time is 20-30 h.

6. A method for synthesizing adamantylphosphine through a free radical phosphination reaction according to claim 1, characterized in that: The molar ratio of adamantane to the radical initiator is 1:1-1.5, the molar ratio of adamantane to potassium phosphate is 1:1-1.5, the molar ratio of adamantane to lithium carbonate is 1:0.5-1, and the molar ratio of adamantane to the phosphorus reagent is 1:0.4-0.5.

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