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Suzuki reaction method of aryl boric acid/boric acid ester containing large steric hindrance substituent

A technology based on aryl boronic acid and Suzuki reaction, which is applied in the direction of organic chemistry, can solve the problems of difficult reaction of large hindered groups, high difficulty of synthesis, and industrialization of new catalysts, so as to reduce experimental costs, shorten reaction time, and reduce side effects. Response reduction effect

Pending Publication Date: 2021-12-24
UNIV OF SCI & TECH BEIJING +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, with the gradual complexity of organic molecule design, some substrates are difficult to carry out under the conventional conditions of the Suzuki reaction, and the ortho-disubstituted aryl boronic acid or borate substrate is one of them; therefore, how to change the reaction Conditions, so that the coupling reaction can be carried out effectively, while retaining the advantages of mild conditions and high selectivity of the Suzuki reaction has become a difficult problem in the industry
[0003] In the exploration of synthetic methods, it is possible to solve the problem that large steric hindrance groups are difficult to react by synthesizing palladium catalyst ligands with stronger electron-rich properties and greater steric hindrance. Therefore, in the traditional Suzuki reaction conditions, it is of great significance to find simpler ideas and synthesis methods

Method used

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  • Suzuki reaction method of aryl boric acid/boric acid ester containing large steric hindrance substituent
  • Suzuki reaction method of aryl boric acid/boric acid ester containing large steric hindrance substituent
  • Suzuki reaction method of aryl boric acid/boric acid ester containing large steric hindrance substituent

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Example 1: Preparation of 3,3'-bis(s-trimethylphenyl)-2,2'-bithiophene

[0029]

[0030] The specific description of the preparation reaction formula is as follows:

[0031] Add 2g of 3,3'-dibromo-[2,2'-bithiophene]-5,5'-bis(trimethylsilane) and 0.3g of tetrakis(triphenylphosphine)palladium into the two-necked flask, Stir and add 45ml of ethylene glycol dimethyl ether under an argon-protected atmosphere until dissolved, dissolve 2.8g of 2,4,6-trimethylphenylboronic acid in 30ml of ethylene glycol dimethyl ether and add to the reaction system, then add 3.3g Potassium tert-butoxide was dissolved in 30ml tert-butanol and added to the reaction system, reacted at 90°C for 0.5h, and purified by column chromatography to obtain a white solid 3,3'-di(mesityl)-2,2' -Bithiophene, yield 80%.

[0032] Such as figure 1 Shown, NMR analysis results: 1 H NMR (300MHz, CDCl 3 )(ppm): δ7.34(d,2H),7.16–7.10(m,6H),7.08(d,2H),7.06–7.00(m,4H).

[0033] Its molecular weight was 402.61 ...

Embodiment 2

[0034] Example 2: Preparation of 3,3'-bis(2,4,6-triisopropylphenyl)-2,2'-bithiophene

[0035]

[0036] The specific description of the preparation reaction formula is as follows:

[0037] 1) when adopting the reaction condition identical with embodiment 1

[0038] Dissolve 2g of 3,3'-dibromobithiophene, 6.12g of (2,4,6-triisopropylphenyl)boronic acid, and 400mg of tetrakis(triphenylphosphine)palladium in ethylene glycol dimethyl ether, Finally, 4.85g of potassium tert-butoxide was dissolved in tert-amyl alcohol and added to the reaction system. The reaction was stirred in an oil bath at 90°C. The stirring was continued for about 96 hours. After purification by column chromatography, 3,3'-bis(2, 4,6-triisopropylphenyl)-2,2'-bithiophene is a white solid with a yield of 35%.

[0039] 2) when adopting another solvent system and temperature of reaction in this technical scheme

[0040] Since the steric hindrance effect in 2,4,6-triisopropylphenylboronic acid is relatively lar...

Embodiment 3

[0044] Example 3: Preparation of 3,3'-bis(4-hexyloxy-2,6-dimethylbenzene)-2,2'-bithiophene

[0045]

[0046] 1) when adopting the reaction condition identical with embodiment 1

[0047] 3.24g 3,3'-dibromobithiophene, 13.3g 2-(4-hexyloxy-2,6-xylene)-4,4,5,5-tetramethyl-1,3,2-di Dissolve oxaborane and 650mg tetrakis(triphenylphosphine)palladium in ethylene glycol dimethyl ether, then dissolve 7.86g potassium tert-butoxide in tert-amyl alcohol and add to the reaction system, and stir in an oil bath at 90°C reaction, the raw materials decompose, and the product cannot be obtained.

[0048] 2) When adopting the second reaction condition in Example 2, due to the further increase of temperature, the decomposition of raw materials is more rapid, and the product cannot be obtained.

[0049] 3) when adopting another solvent system, alkali and temperature of reaction in this technical scheme

[0050] 3,3'-dibromodithiophene 0.01mol, 2-((4-hexyloxy)-2,6-xylene)-4,4,5,5-tetramethyl-1...

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Abstract

The invention provides a Suzuki reaction method of aryl boric acid / boric acid ester containing a large steric hindrance substituent, the reaction has the characteristics as shown in a formula I, and Ar represents a compound with a conjugated structure; R1 represents alkyl containing 2-18 carbon atoms, Y1 represents alkyl containing 1-18 carbon atoms, alkoxy, alkylthio, ester group and other groups; and B represents a di-oxapentaborane group or a boric acid group. According to the method provided by the invention, proper solvents such as ethylene glycol dimethyl ether, diethylene glycol dimethyl ether and the like are matched with a common palladium catalyst to form a reaction system, so that the problem that Suzuki reaction with large steric hindrance groups is difficult to carry out is effectively solved.

Description

【Technical field】 [0001] The invention belongs to the technical field of organic synthetic chemistry, and specifically relates to a Suzuki reaction method containing a large sterically hindered substituent aryl boronic acid / boronic acid ester, in particular to a Suzuki reaction in which the substrate is an ortho-disubstituted aryl boronic acid or boric acid ester synthetic method. 【Background technique】 [0002] The Suzuki reaction is a palladium-catalyzed coupling reaction between organoboron compounds and organic halides. Because of its relatively mild reaction conditions and high selectivity to functional groups, it is the easiest to use in palladium-catalyzed coupling reactions. One of the linked reactions. However, with the gradual complexity of organic molecule design, some substrates are difficult to carry out under the conventional conditions of the Suzuki reaction, and the ortho-disubstituted aryl boronic acid or borate substrate is one of them; therefore, how to c...

Claims

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Application Information

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IPC IPC(8): C07D333/08C07D333/16
CPCC07D333/08C07D333/16
Inventor 张少青戴江波侯剑辉
Owner UNIV OF SCI & TECH BEIJING
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