阅读说明：本技术 一种含双膦间位碳硼烷配体的铂配合物及其制备方法和应用 (Platinum complex containing diphosphine meta-carborane ligand and preparation method and application thereof ) 是由 姚子健 王松涛 于 2020-12-23 设计创作，主要内容包括：本发明涉及一种含双膦间位碳硼烷配体的铂配合物及其制备方法和应用,该铂配合物的方法为：将n-BuLi与间位碳硼烷m-C-2B-(10)H-(12)反应,然后加入卤代膦继续反应,再将(COD)PtCl-2加入反应体系接着反应,反应结束后分离得到含双膦间位碳硼烷配体的铂配合物,应用在催化苯酚类化合物与丙烯酸乙酯的直接偶联反应中。与现有技术相比,本发明催化活性高,催化剂用量低,反应条件温和,反应速率快,产率较高,底物范围广,原料廉价易得。(The invention relates to a platinum complex containing diphosphine meta-carborane ligand, a preparation method and application thereof, wherein the method for preparing the platinum complex comprises the following steps: reacting n-BuLi with m-carborane 2 B 10 H 12 Reacting, adding halogenated phosphine, continuing the reaction, and adding (COD) PtCl 2 Adding the platinum complex into a reaction system for reaction, separating after the reaction is finished to obtain the platinum complex containing the diphosphonic meta-carborane ligand, and applying the platinum complex to catalyzing the direct coupling reaction of the phenol compound and the ethyl acrylate. Compared with the prior art, the invention has high catalytic activity and is used as a catalystLow amount, mild reaction condition, high reaction speed, high yield, wide substrate range and cheap and easily-obtained raw materials.)

1. A platinum complex containing diphosphine meta-carborane ligand is characterized in that the structural formula of the platinum complex is as follows:

wherein R is-Ph, 4-MeO-C₆H₄-、4-NO₂-C₆H₄-or-ⁱPr, "·" is a boron hydrogen bond.

2. A process for the preparation of a platinum complex containing a bis-phosphonocarborane ligand according to claim 1, comprising: reacting n-BuLi with m-carborane m-C₂B₁₀H₁₂Reacting, adding halogenated phosphine, continuing the reaction, and adding (COD) PtCl₂Adding the mixture into a reaction system for reaction, and separating after the reaction is finished to obtain the platinum complex containing the diphosphine m-carborane ligand.

3. The process according to claim 2, wherein the meta-carborane, n-BuLi, phosphine halide and (COD) PtCl are used as the ligand in the preparation of the platinum complex containing diphosphine meta-carborane ligand₂The molar ratio of (1.0), (2.2-2.5), (2.5-3.0) to (1.0).

4. The preparation method of the platinum complex containing diphosphine meta-carborane ligand according to claim 2, characterized by comprising the following steps:

(1) dropwise addition of n-BuLi solution to m-C of m-carborane at low temperature₂B₁₀H₁₂Stirring in the solution;

(2) heating to room temperature, and reacting;

(3) adding halogenated phosphine, and continuing to react;

(4) reacting (COD) PtCl₂Adding the raw materials into a reaction system for reaction, decompressing and draining the solvent after the reaction is finished, and washing and draining the obtained crude product to obtain the platinum complex containing the diphosphonic meta-carborane ligand.

5. The method for preparing the platinum complex containing diphosphine-m-carborane ligand according to claim 4, wherein the low temperature in the step (1) is-5 to 5 ℃; the n-BuLi solution is n-BuLi n-hexane solution, and the m-C solution is₂B₁₀H₁₂The solution is m-C₂B₁₀H₁₂Ether solution; the stirring time is 20-40 min; the re-reaction time in the step (2) is 20-40 min.

6. The method for preparing a platinum complex containing diphosphine meta-carborane ligand according to claim 4, wherein the halophosphine in step (3) comprisesInclude ClPPh₂、ClP(4-MeO-C₆H₄)₂、ClP(4-NO₂-C₆H₄)₂Or ClCH₂PⁱPr₂(ii) a The continuous reaction time is 1-3 h; and (4) carrying out subsequent reaction at the temperature of 50-80 ℃ for 5-8h, and washing by using diethyl ether as a detergent.

7. Use of a platinum complex containing a bisphosphine carborane ligand according to claim 1, for catalyzing the direct coupling reaction of a phenolic compound with ethyl acrylate.

8. The application of the platinum complex containing diphosphine meta-carborane ligand according to claim 7 is characterized in that the specific application method comprises the following steps: platinum complex, phenol derivative, ethyl acrylate and Na₂CO₃Dissolving in methanol, reacting at room temperature, separating and purifying to obtain the ortho-allylated coupling product.

9. The use of a platinum complex containing a bis-phosphine-m-carborane ligand according to claim 7, wherein said platinum complex, phenol derivative, ethyl acrylate and Na₂CO₃The molar ratio of (0.005-0.01) to (1.0: 1.1: 1.5), and the reaction time is 3-6 h.

10. The use of a platinum complex containing a bisphosphine meta-carborane ligand according to claim 7, wherein the phenol derivative is selected from the group consisting of phenols with different electronic and steric substituents, specifically comprising phenol, 4-methylphenol, 4-n-butylphenol, 4-tert-butylphenol, 4-phenylphenol, 4-fluorophenol, 4-chlorophenol, 4-nitrophenol, 3-methylphenol, 3-methoxyphenol, 3-chlorophenol, and 2-methylphenol.

Technical Field

The invention relates to the field of complex synthesis, in particular to a platinum complex containing diphosphine meta-carborane ligand and a preparation method and application thereof.

Background

The o-alkenylphenol is a key intermediate for synthesizing a series of natural products, so that the development of a high-efficiency strategy for realizing the ortho-position selective alkenylation of the phenol has important significance.

The classical ortho-alkenylation of phenol is achieved by the Claisen rearrangement of alpha-allylphenol. However, this method has disadvantages in that it is difficult to control the selectivity of the reaction, and a multi-site substitution product may be produced. In recent years, direct ortho-alkenylation of phenol is realized by the aid of a guide group, and a new method is provided for ortho-alkenylation of phenol. In 2011, the Gevorgyan project group reported ortho-olefination reactions of silyl ether-oriented phenols; in the same year, Liu Lei task group reported Rh catalyzed carbamate-oriented phenol ortho-olefination, 2013, Luxi Yan and the like successfully realized phenol ortho-olefination by adopting oxidative guide groups, and Zhao Yisheng group in 2020 realized the reaction by using acetone oxime amidine as a guide group and rhodium as a catalyst in the presence of silver acetate.

Although these methods all achieve ortho-alkenylation of phenol, they all suffer from drawbacks, such as the synthesis of the substrate requiring several synthesis steps; the guide group is not easy to leave in the reaction process, and the alpha-alkenyl phenol can be obtained only by subsequent conversion; the directing group is not easy to synthesize or unstable, or is expensive; and the reaction conditions all need higher temperature and the like; these limit the application of these methods to some extent.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a platinum complex containing diphosphine m-carborane ligand, which has the advantages of high catalytic activity, low catalyst dosage, mild reaction condition, high reaction rate, high yield, wide substrate range, cheap and easily-obtained raw materials, and a preparation method and application thereof.

The purpose of the invention can be realized by the following technical scheme:

a platinum complex containing diphosphine meta-carborane ligand is shown as the following structural formula:

wherein R is-Ph, 4-MeO-C₆H₄-、4-NO₂-C₆H₄-or-ⁱPr, "·" is a boron hydrogen bond.

Further, the platinum complex comprises a platinum complex 1, a platinum complex 2, a platinum complex 3 and a platinum complex 4, and the structural formula is as follows:

a method for preparing the platinum complex containing diphosphine m-carborane ligand, which comprises the following steps: reacting n-BuLi with m-carborane₂B₁₀H₁₂Reacting, adding halogenated phosphine, continuing the reaction, and adding (COD) PtCl₂Adding the mixture into a reaction system for reaction, and separating after the reaction is finished to obtain the platinum complex containing the diphosphine m-carborane ligand, wherein the reaction formula is as follows:

the method has the advantages of mild reaction conditions, good universality, high yield, simple product separation, insensitivity of the product to air and water and stable property. The complex can catalyze the direct coupling of phenol compounds and ethyl acrylate to realize the direct ortho-allylation of phenol, and has the advantages of low catalyst consumption, mild reaction conditions, high reaction rate, high yield, wide substrate range and wide industrial application prospect.

Further, the meta-carborane, n-BuLi, phosphine halide and (COD) PtCl₂The molar ratio of (1.0), (2.2-2.5), (2.5-3.0) to (1.0).

Further, the method specifically comprises the following steps:

(1) dropwise addition of n-BuLi solution to m-C of m-carborane at low temperature₂B₁₀H₁₂Stirring in the solution;

(2) heating to room temperature, and reacting;

(3) adding halogenated phosphine, and continuing to react;

(4) reacting (COD) PtCl₂Adding the mixture into a reaction system for reaction, decompressing and draining the solvent after the reaction is finished, washing and draining the obtained crude product to obtain the meta-carbon containing diphosphinePlatinum complexes of borane ligands.

Further, the low temperature in the step (1) is-5 to 5 ℃; the n-BuLi solution is n-BuLi n-hexane solution, and the m-C solution is₂B₁₀H₁₂The solution is m-C₂B₁₀H₁₂Ether solution; the stirring time is 20-40 min; the re-reaction time in the step (2) is 20-40 min.

Further, the halogenated phosphine described in the step (3) includes ClPPh₂、ClP(4-MeO-C₆H₄)₂、ClP(4-NO₂-C₆H₄)₂Or ClCH₂PⁱPr₂(ii) a The continuous reaction time is 1-3 h; and (4) carrying out subsequent reaction at the temperature of 50-80 ℃ for 5-8h, and washing by using diethyl ether as a detergent.

Use of a platinum complex containing a bisphosphine carborane ligand according to claim 1, in catalyzing a direct coupling reaction of a phenolic compound with ethyl acrylate.

Further, the specific application method comprises the following steps: platinum complex, phenol derivative, ethyl acrylate and Na₂CO₃Dissolving in methanol, reacting at room temperature, separating and purifying to obtain the ortho-allylated coupling product.

Further, the platinum complex, the phenol derivative, the ethyl acrylate and the Na₂CO₃The molar ratio of (0.005-0.01) to (1.0: 1.1: 1.5), and the reaction time is 3-6 h.

Further, the phenol derivative is selected from phenols with different electronic and stereo-effect substituents, and specifically comprises phenol, 4-methylphenol, 4-n-butylphenol, 4-tert-butylphenol, 4-phenylphenol, 4-fluorophenol, 4-chlorophenol, 4-nitrophenol, 3-methylphenol, 3-methoxyphenol, 3-chlorophenol or 2-methylphenol.

Compared with the prior art, the invention has the following advantages:

(1) the preparation method of the diphosphorus-containing meta-carborane Pincer platinum complex is simple, the complex can be prepared in high yield through one-pot reaction and can stably exist in the air;

(2) the Pincer platinum complex can efficiently catalyze the direct coupling reaction of a phenol compound and ethyl acrylate to realize the ortho-position allylation of phenol, and has the advantages of good selectivity, low catalyst consumption, mild reaction conditions, high reaction rate, high yield, wide substrate range, cheap and easily-obtained raw materials and wide industrial application prospect.

Detailed Description

The following examples are given for the detailed implementation and specific operation of the present invention, but the scope of the present invention is not limited to the following examples.

Example 1: synthesis of diphosphine-containing m-carborane Pincer platinum complex 1 and ortho-allylation reaction for catalyzing phenol derivative and ethyl acrylate

n-BuLi (2.2mmol) in n-hexane was added dropwise to the m-C m-carborane at 0 deg.C₂B₁₀H₁₂(1.0mmol) of the obtained product in ether solution, continuously stirring for 30 minutes after dropwise adding, slowly raising the temperature to room temperature, continuously reacting for 30 minutes, and adding halogenated phosphine ClCH₂PⁱPr₂(2.5mmol) and continued reaction at room temperature for 3 hours, after which (COD) PtCl was added₂(1.0mmol) is added into a reaction system to continue reacting for 6 hours at 50 ℃, after the reaction is finished, standing and filtering are carried out, the solvent is pumped out under reduced pressure, the obtained crude product is washed by ether, and the crude product is pumped out to obtain a target product 1 (the yield is 85 percent), and the reaction formula is as follows:

¹H NMR(400MHz,CDCl₃25 ℃ delta. is 3.09(s,4H),2.55-2.47(m,4H),1.15-0.98(m,24H)₁₆B₁₀H₄₁ClP₂Pt: c30.31, H6.52; experimental values: c30.36, H6.59.

In a reaction tube, a Pincer platinum complex 1(0.005mmol), phenolDerivative (1.0mmol), ethyl acrylate (1.1mmol) and Na₂CO₃(1.5mmol) is dissolved in 2mL of methanol, the reaction is carried out for 5 hours at room temperature, after the reaction is finished, the reaction solution is concentrated, the crude product is separated and purified by column chromatography, and the eluent is petroleum ether: ethyl acetate 8:1 to obtain the coupled product, and the specific results are shown in table 2, and the reaction formula is as follows:

TABLE 2

Example 2: synthesis of diphosphine-containing meta-carborane Pincer platinum complex 2

n-BuLi (2.4mmol) in n-hexane was added dropwise to the m-C m-carborane at 0 deg.C₂B₁₀H₁₂(1.0mmol) of the obtained product in ether solution, continuously stirring for 30 minutes after dropwise adding, slowly raising the temperature to room temperature, continuously reacting for 30 minutes, and adding halogenated phosphine ClCH₂PPh₂(2.8mmol) and continued reaction at room temperature for 3 hours, after which (COD) PtCl was added₂(1.0mmol) is added into a reaction system to continue reacting for 8 hours at 50 ℃, after the reaction is finished, standing and filtering are carried out, the solvent is pumped out under reduced pressure, the obtained crude product is washed by ether, and the crude product is pumped out to obtain a target product 2 (the yield is 88%), and the reaction formula is as follows:

¹H NMR(400MHz,CDCl₃25 ℃ delta. 7.69-7.60(m,8H),7.51-7.42(m,12H),3.08(s,4H). theoretical value of elemental analysis C₂₈B₁₀H₃₃ClP₂Pt: c43.67, H4.32; experimental values: c43.61, H4.35.

Example 3: synthesis of diphosphine-containing meta-carborane Pincer platinum complex 3

n-BuLi (2.5mmol) in n-hexane was added dropwise to the m-C m-carborane at 0 deg.C₂B₁₀H₁₂(1.0mmol) of the obtained product in ether solution, continuously stirring for 30 minutes after dropwise adding, slowly raising the temperature to room temperature, continuously reacting for 30 minutes, and adding halogenated phosphine ClCH₂P(4-MeO-C₆H₄)₂(3.0mmol) and continued reaction at room temperature for 3 hours, after which (COD) PtCl was added₂(1.0mmol) is added into a reaction system to continue reacting for 5 hours at 80 ℃, after the reaction is finished, standing and filtering are carried out, the solvent is pumped out under reduced pressure, the obtained crude product is washed by ether, and the crude product is pumped out to obtain a target product 3 (the yield is 86 percent), and the reaction formula is as follows:

¹H NMR(400MHz,CDCl₃25 ℃ C.: delta. 7.75-7.63(m,8H),7.47-7.40(m,8H),3.63(s,12H),3.01(s,4H). theoretical value of elemental analysis C₃₂B₁₀H₄₁ClO₄P₂Pt: c43.17, H4.64; experimental values: c43.22, H4.65.

Example 4: synthesis of diphosphine-containing m-carborane Pincer platinum complex 4

n-BuLi (2.2mmol) in n-hexane was added dropwise to the m-C m-carborane at 0 deg.C₂B₁₀H₁₂(1.0mmol) of the obtained product in ether solution, continuously stirring for 30 minutes after dropwise adding, slowly raising the temperature to room temperature, continuously reacting for 30 minutes, and adding halogenated phosphine ClCH₂P(4-NO₂-C₆H₄)₂(2.8mmol) and continued reaction at room temperature for 3 hours, after which (COD) PtCl was added₂(1.0mmol) is added into the reaction system to continue the reaction for 6 hours at 60 ℃, after the reaction is finished, the mixture is stood and filtered, and the pressure is reduced and the mixture is pumped outThe solvent was dried and the crude product was washed with ether and dried by suction to give the desired product 4 (89% yield) of the formula:

¹H NMR(400MHz,CDCl₃25 ℃ C.). delta. 7.80-7.72(m,8H),7.63-7.57(m,12H),3.15(s, 4H.) theoretical value of elemental analysis C₂₈B₁₀H₂₉ClN₄O₈P₂Pt: c35.40, H3.08, N5.90; experimental values: c35.48, H3.05, N5.96.

Pincer platinum complex 1-4 for catalyzing ortho-allylation reaction of phenol and ethyl acrylate

In a reaction tube, a Pincer platinum complex, phenol (1.0mmol), ethyl acrylate (1.1mmol) and Na₂CO₃Dissolving (1.5mmol) in 2mL of methanol, reacting at room temperature for 3-6 hours, concentrating the reaction solution after the reaction is finished, separating and purifying the crude product by column chromatography, wherein the eluent is petroleum ether: ethyl acetate 8:1, i.e. the ortho-allylated coupling product, the specific results are shown in table 1, and the reaction formula is:

TABLE 1

Serial number	Catalyst and process for preparing same	Amount of catalyst (mmol)	Reaction time (h)	Yield (%)
					1	1	0.005	3	68
2	1	0.005	5	94
					3	1	0.005	6	93
4	1	0.008	6	94
					5	1	0.01	6	95
6	2	0.005	5	92
					7	3	0.005	5	95
8	4	0.005	5	93

The embodiments described above are described to facilitate an understanding and use of the invention by those skilled in the art. It will be readily apparent to those skilled in the art that various modifications to these embodiments may be made, and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above embodiments, and those skilled in the art should understand that they can make various modifications, changes, substitutions, combinations, and the like equivalent to the embodiments without departing from the scope of the present invention.