阅读说明：本技术 有机铁盐作为催化剂在合成烷基硼酯化合物中的应用 (Application of organic iron salt as catalyst in synthesis of alkyl boron ester compound ) 是由 孙宏枚 周巧云 于 2017-10-27 设计创作，主要内容包括：本发明公开了有机铁盐作为催化剂在合成烷基硼酯化合物中的应用,即以Fe(acac)<Sub>3</Sub>(acac=乙酰丙酮基)为单组份催化剂、在金属镁的存在下、通过氯代烷烃与联硼酸频那醇酯的交叉偶联反应合成烷基硼酯化合物的方法。本发明提供的合成烷基硼酯化合物的方法既避免了敏感金属有机试剂和多组份催化剂的使用,又实现了联硼酸频那醇酯的双边利用、显著减少了联硼酸频那醇酯的用量,在温和条件下可使价廉易得的氯代烷烃参与的偶联反应顺利进行；与文献报道的相比,具有更好的原子经济性、相当或更高的催化效率和更广的底物适用性。(The invention discloses an application of organic ferric salt as a catalyst in the synthesis of an alkyl boron ester compound, namely Fe (acac) 3 (acac = acetylacetone group) is a single-component catalyst, and under the existence of metal magnesium, the method for synthesizing the alkyl boron ester compound through the cross-coupling reaction of chloralkane and pinacol ester diboron acid. The method for synthesizing the alkyl boron ester compound provided by the invention not only avoids the use of sensitive metal organic reagents and multi-component catalysts, but also realizes the bilateral utilization of the diboron pinacol ester, obviously reduces the dosage of the diboron pinacol ester, and can smoothly carry out the coupling reaction with cheap and easily obtained chloralkane under mild conditions; better atom economy, comparable or higher catalytic efficiency and broader substrate applicability than reported in the literature.)

1. The application of organic iron salt as a catalyst in the synthesis of alkyl boron ester compounds; the organic ferric salt is ferric acetylacetonate.

2. The application of claim 1, wherein the method for synthesizing the alkyl boron ester compound comprises the following steps of taking halogenated alkane and pinacol diboron as raw materials, and reacting the halogenated alkane and the pinacol diboron in the presence of magnesium under the catalysis of organic iron salt to prepare the alkyl boron ester compound; the halogenated alkane is chlorinated alkane.

3. Use according to claim 1, wherein the reaction is carried out in an organic solvent; the reaction temperature is-20 ℃ to 0 ℃, and the reaction time is 2 to 10 hours.

4. The use according to claim 3, wherein the reaction temperature is 0 ℃ and the reaction time is 3 hours.

5. The method for preparing boron alkyl ester according to claim 1, wherein the reaction is terminated by adding water after the reaction is finished, and the boron alkyl ester compound is obtained by extracting with ethyl acetate.

6. The use according to claim 1, wherein the molar ratio of the haloalkane, pinacol diboron, organic iron salt and magnesium is 2.7:1:0.02: 1.4.

Technical Field

The invention belongs to the technical field of preparation of organic compounds, and particularly relates to a novel preparation method of an alkyl boron ester compound.

Background

Boron ester compounds are synthetic intermediates of many natural products and drug molecules, and are also basic reactants of Suzuki-Miyaura coupling reaction, so how to synthesize the compounds efficiently and conveniently has been concerned (see: R.Jana, T.P. Pathak, M.S. Sigman,Chem. Rev., 2011, 111, 1417）。

in recent years, cross-coupling reaction of halogenated alkane and diborate ester reagent catalyzed by transition metal catalyst is developed successively to synthesize alkyl boron ester compound, mainly involving metal catalysts such as palladium, nickel, copper, zinc, iron, etc. Among them, the iron-based catalyst is considered to be an important strategy for developing more economical, greener and efficient catalysts due to the advantages of low price, easy availability, low toxicity or no toxicity, good biocompatibility and the like. However, the existing methods for synthesizing borate compounds have some significant drawbacks, such as: (1) for the pinacol diboron, only one side participates in the reaction, so the pinacol diboron is used excessively, and the atom economy is poor; (2) dangerous or sensitive metal organic reagents are added in the reaction to activate the diboron pinacol ester; (3) in addition to an iron source, other inorganic salts or nitrogen-containing ligands are required to be added into the catalytic system; (4) the developed catalytic system has poor substrate adaptability, particularly has very low catalytic activity on chloroalkane substrates with more price advantage and diversity, and cannot be industrially produced. Therefore, it is of great significance to develop a new method for synthesizing the alkyl boron ester compound more safely, more efficiently and economically by using the single-component iron catalyst with a definite structure.

Disclosure of Invention

The invention aims to provide a preparation method with simple raw material source, stable reaction process and simple and convenient operation, and a novel method for preparing an alkyl boron ester compound simply, safely and efficiently, namely Fe (acac)₃Synthesizing alkyl boron ester compound by cross coupling reaction of chlorohydrocarbon alkane and diboron acid pinacol ester in the presence of metal magnesium as a catalyst, wherein the diboron acid isThe structure of the Naol ester is:

in order to achieve the purpose of the invention, the technical scheme adopted by the invention is as follows:

a method for synthesizing an alkyl boron ester compound comprises the following steps of taking halogenated alkane and pinacol diboron as raw materials, and reacting in the presence of magnesium under the catalysis of organic iron salt to prepare the alkyl boron ester compound.

The invention also discloses the application of the organic ferric salt as a catalyst in synthesizing the alkyl boron ester compound; preferably, when the alkyl boron ester compound is synthesized, halogenated alkane and diboron pinacol ester are used as raw materials, and magnesium is used as an additive.

The invention also discloses application of the organic ferric salt as a catalyst in catalyzing reaction of halogenated alkane and diboron pinacol ester; preferably, the reaction of the haloalkane with pinacol ester of diboronic acid is carried out in the presence of magnesium.

The invention also discloses the application of the halogenated alkane and the diboron acid pinacol ester as raw materials in synthesizing the alkyl boron ester compound; preferably, when the alkyl boron ester compound is synthesized, organic iron salt is used as a catalyst, and magnesium is used as an additive.

In the above technical scheme, the reaction is carried out in an organic solvent; the reaction temperature is-20 ℃ to 0 ℃, and the reaction time is 2 to 10 hours; the reaction temperature is preferably 0 ℃ and the reaction time is preferably 3 hours.

In the technical scheme, after the reaction is finished, water is added to stop the reaction, the reaction product is extracted by ethyl acetate, and quantitative analysis is carried out by column chromatography or gas chromatography, wherein the yield mainly takes the gas yield, and the nuclear magnetic spectrum is obtained by separation.

In the technical scheme, the molar ratio of the halogenated alkane to the pinacol diboron to the organic ferric salt to the magnesium is 2.7:1:0.02: 1.4; the dosage of the halogenated alkane and the pinacol ester diborate is reversed, the raw material proportion considered in the field is overturned, the bilateral complete utilization of the pinacol ester diborate is realized, the atom economy of the reaction is greatly improved, the product yield is high, and unexpected technical effects are achieved.

In the invention, the halogenated alkane is chlorinated alkane, and the chlorinated alkane is preferably benzyl chloride compound; the organic iron salt is ferric acetylacetonate, i.e. Fe (acac)₃Acac is an acetylacetonate group.

In particular, the invention discloses a Fe (acac)₃The method is used for catalyzing the coupling reaction of chloralkane and pinacol ester diborate by a catalyst, and comprises the following steps:

[1] sequentially adding a catalyst, pinacol diboron and magnesium chips into a reactor, adding a solvent tetrahydrofuran, adding chloroalkane at the temperature of-20-0 ℃, and reacting for 3-10 hours at the temperature;

[2] after the reaction is finished, adding water to stop the reaction, extracting a reaction product by using ethyl acetate, and carrying out quantitative analysis by using column chromatography or gas chromatography, wherein the yield mainly takes the gas yield, and the nuclear magnetic spectrum is obtained by separation.

The principle of the invention is as follows: metal magnesium and benzyl chloride generate benzyl magnesium chloride in situ, the benzyl magnesium chloride activates pinacol diboron to perform cross coupling reaction with boron ester on one side under the action of an iron catalyst to generate a molecule of benzyl boron ester product, and boron ester on the other side can perform cross coupling reaction with the benzyl chloride to generate another molecule of benzyl boron ester product, so that two molecules of benzyl boron ester product can be obtained in the whole reaction.

The reaction formula of the present invention can be exemplified as follows:

due to the application of the technical scheme, compared with the prior art, the invention has the following advantages:

1. according to the invention, the dosage of the halogenated alkane and the pinacol ester diborate is reversed, and the feeding ratio of the pinacol ester diborate to the halogenated alkane is 1:2.7 (molar ratio), so that bilateral complete utilization of the pinacol ester diborate is realized, the atom economy of the reaction is greatly improved, and the bilateral utilization of the pinacol ester diborate is the first instance of bilateral utilization of the pinacol ester diborate realized by an iron-based catalyst.

2. In the invention, metal magnesium is used for replacing metal organic reagents, so that the use of dangerous or sensitive metal organic reagents is avoided.

3. The invention adopts the single-component iron catalyst, and does not need to add extra ligand.

4. The preparation method disclosed by the invention has universality for various reaction substrates, particularly can efficiently catalyze cross-coupling reaction with chloroalkane, has relatively easy raw material source and low cost, and is beneficial to industrial production of alkyl boron ester compounds.

Detailed Description

The invention is further described below with reference to the following examples: