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Preparation method of benzyl boron ester compound

A technology of benzyl boronic esters and compounds, which is applied in the field of organic synthesis, can solve the problems of substrate functional group tolerance, high cost, and unfriendly environment, and achieve mild reaction conditions, simple operation, and low reaction cost. Effect

Inactive Publication Date: 2016-08-24
PEKING UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, these methods have certain disadvantages. For example, the former requires the use of highly active organometallic reagents, and there are certain problems in the tolerance of substrate functional groups, while the latter requires the use of relatively expensive transition metal catalysts, which are costly and harmful to the environment. not friendly enough

Method used

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  • Preparation method of benzyl boron ester compound
  • Preparation method of benzyl boron ester compound
  • Preparation method of benzyl boron ester compound

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] Synthesis of Benzylboronic Acid Pinacol Ester

[0035] Add 49mg (0.4mmol) of phenylboronic acid and 0.4mL (0.8mmol) of trimethylsilyldiazomethane (2M n-hexane solution) to a 10mL reaction tube equipped with magnetons, and add 1mL of 1,4-bis Oxyhexane, plugged with a rubber stopper, and reacted on a 50°C electromagnetic heating stirrer for 4 hours. Then add pinacol (dissolved in 1mL 1,4-dioxane) 71mg (0.6mmol), tetrabutylammonium fluoride (1M tetrahydrofuran solution) 0.4mL and 200uL water respectively, and stirrer with electromagnetic heating at 50 ℃ The reaction was continued for 4 hours. After the reaction is completed, the organic solvent is removed by a rotary evaporator, and purified by column chromatography to obtain benzylboronic acid pinacol ester, whose structure is shown in the following formula:

[0036]

[0037] The productive rate is 76% under the above conditions;

[0038] Other conditions remain unchanged, when the heating temperature is 40°C, the y...

Embodiment 2

[0047] Synthesis of 4-methylbenzylboronic acid pinacol ester

[0048] Add 54mg (0.4mmol) of 4-methylphenylboronic acid and 0.4mL (0.8mmol) of trimethylsilyldiazomethane (2M n-hexane solution) to a 10mL reaction tube equipped with a magnet, and add 1mL of 1 , 4-dioxane, plugged with a rubber stopper, and reacted on an electromagnetic heating stirrer at 50°C for 3 hours. Then add 47mg (0.4mmol) of pinacol (dissolved in 1mL 1,4-dioxane), 0.4mL of tetrabutylammonium fluoride (1M tetrahydrofuran solution) and 200uL water respectively, and stirrer with electromagnetic heating at 50°C The reaction was continued for 3 hours. After the reaction, the organic solvent was removed by a rotary evaporator, and purified by column chromatography to obtain 4-methylbenzylboronic acid pinacol ester, whose structure is shown in the following formula:

[0049]

[0050] The compound is a colorless liquid with a yield of 68%, and its NMR data are as follows:

[0051] 1 H NMR (400MHz, CDCl 3 )...

Embodiment 3

[0053] Synthesis of 4-tert-butylbenzylboronic acid pinacol ester

[0054] Add 71mg (0.4mmol) of 4-tert-butylphenylboronic acid and 0.4mL (0.8mmol) of trimethylsilyldiazomethane (2M n-hexane solution) to a 10mL reaction tube equipped with a magnet, and add 1mL of 1,4-dioxane, plugged with a rubber stopper, and reacted on an electromagnetic heating stirrer at 40°C for 4 hours. Then add pinacol (dissolved in 1mL 1,4-dioxane) 94mg (0.8mmol), tetrabutylammonium fluoride (1M tetrahydrofuran solution) 0.2mL and 200uL water respectively, and stirrer with electromagnetic heating at 40°C The reaction was continued for 4 hours. After the reaction, the organic solvent was removed by a rotary evaporator, and purified by column chromatography to obtain 4-tert-butylbenzylboronic acid pinacol ester, whose structure is shown in the following formula:

[0055]

[0056] The compound is a colorless liquid with a yield of 71%, and its NMR data are as follows:

[0057] 1 H NMR (400MHz, CDCl ...

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Abstract

The invention discloses a preparation method of a benzyl boron ester compound. According to the preparation method, aromatic boric acid Ar-B(OH)2, trimethyl silicon-based diazomethane, pinacol and tetrabutyl ammonium fluoride are subjected to a reaction in an organic solvent so as to obtain a benzyl pinacol boron ester compound, wherein Ar represents a non-heterocyclic aromatic group. After the method is adopted, the benzyl boron ester compound is obtained by starting from the aromatic boric acid and converting under a one-pot condition; the method is mild in reaction conditions, the reaction related to the method occurs smoothly in the air without needing strict water-free and oxygen-free conditions, and the method is convenient and simple to operate; the method has better tolerance and universality for functional groups and does not need an expensive metal catalyst and a ligand, thus being lower in reaction cost and being widely used for preparing the benzyl boron ester compound.

Description

technical field [0001] The invention belongs to the field of organic synthesis, in particular to a preparation method of benzyl boron ester compound. Background technique [0002] Boron ester compounds are an important class of chemical raw materials, which are widely used in scientific research and industrial production. In scientific research, boron ester compounds are mainly used as a class of synthetic intermediates in cross-coupling reactions catalyzed by transition metals to construct target compounds with relatively complex structures. In industrial production, boron ester compounds have been widely used in the fields of medicine, pesticides and materials. For a long time, people have continuously improved and perfected the synthetic method of boron ester compounds. At present, the synthetic method of aromatic boron ester compounds has been relatively perfect, while the synthetic method of alkyl boron ester compounds, especially benzyl boron ester compounds, remains ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07F5/04
CPCC07F5/04
Inventor 王剑波吴超强吴国骄张艳
Owner PEKING UNIV