Cesium neopentanoate co-catalyzed aryl borate preparation method

A technology of aryl boronate and cesium pivalate, applied in the field of preparation of aryl borate, can solve the problems of difficult separation and purification, low utilization rate of transition metal catalyst, low yield of boron acylation product, etc. The effect of avoiding dehalogenation side reactions, short reaction time and low cost

Pending Publication Date: 2021-09-21
NINGBO POLYTECHNIC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] The traditional method of synthesizing aryl borates is metal catalyzed borylation reaction between halogenated aromatic hydrocarbons and boron reagents. Metal catalysis mostly uses catalysts such as palladium, copper, nickel, rhodium, iridium, ruthenium, etc., and the borylation reaction will vary in degree. The by-product--dehalogenated aromatic hydrocarbons are generated in an unreasonable manner, which leads to low utilization rate of transition metal catalysts, low yield of boroacylation products, and is difficult to separate and purify

Method used

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  • Cesium neopentanoate co-catalyzed aryl borate preparation method
  • Cesium neopentanoate co-catalyzed aryl borate preparation method
  • Cesium neopentanoate co-catalyzed aryl borate preparation method

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] Under the protection of nitrogen, 2.33g of 4-bromobiphenyl (10mmol) and 6.35g of bis-valeryl diboron (25mmol) were dissolved in 50mL of 1,4-dioxane, and then 2.57g of cesium pivalate (11mmol) ), 113mg Pd(OAc)2(0.5mmol) and 262mg PPh 3 (1mmol) of 1,4-dioxane (30ml) was added to the above solution, the reaction heat was raised to 90°C, and the reaction was stirred for 3h. The reaction solution was filtered through celite, the filtrate was collected, concentrated under reduced pressure, and then silica gel column chromatography (eluent: petroleum ether volume: ethyl acetate volume = 10:1) to obtain 2.66 g of the product with a yield of 95%. Purity 98.3% (HPLC).

[0032] 1 H NMR (400MHz, CDCl3) δ7.91(d, J=7.2Hz, 2H), 7.63(d, J=6.8Hz, 2H), 7.58(t, J=6.8, 13.6Hz, 3H), 7.30(d ,J=7.2Hz,2H).1.38(s,12H)ESI-MS, 281.2[M+H] +

[0033]

Embodiment 2

[0035] Under nitrogen protection, 1.85g of p-ethylbromobenzene (10mmol) and 6.35g of bis-valeryl diboron (25mmol) were dissolved in 50mL of 1,4-dioxane, and then 2.57g of cesium pivalate ( 11mmol), 113mg Pd(OAc) 2 (0.5mmol) and 262mg PPh 3 (1mmol) of 1,4-dioxane (30ml) was added to the above solution, the reaction heat was raised to 95°C, and the reaction was stirred for 2h. The reaction solution was filtered through celite, the filtrate was collected, concentrated under reduced pressure, and then silica gel column chromatography (eluent: petroleum ether volume: ethyl acetate volume = 10:1) to obtain 2.20 g of the product with a yield of 94.8%. Purity 99.2% (HPLC).

[0036] 1 H NMR (400MHz, CDCl3) δ7.69 (d, J = 8.4Hz, 2H), 7.08 (d, J = 8.4Hz, 2H), 2.54 (q, J = 6.1, 2H), 1.22 (s, 12H) ,1.33(m,3H,CH 3 ).ESI-MS, 233.2[M+H] +

[0037]

Embodiment 3

[0039] Under nitrogen protection, 2.04g p-3,5-dimethylbromobenzene (11mmol) and 6.35g bisvaleryl diboron (25mmol) were dissolved in 55mL dimethyl sulfoxide, and then 2.81g pivalic acid was dissolved Cesium (12mmol), 113mg Pd(OAc) 2 (0.5mmol) and 314.4mg PPh3 (1.2mmol) of dimethyl sulfoxide (25ml) solution was added to the above solution, the reaction heat was raised to 87°C, and the reaction was stirred for 3h. The reaction solution was filtered through diatomaceous earth, the filtrate was collected, concentrated under reduced pressure, and then silica gel column chromatography (eluent: petroleum ether volume: ethyl acetate volume = 10:1) to obtain 2.37 g of the product with a yield of 92.8%. Purity 98.5% (HPLC).

[0040] 1 H NMR (400MHz, CDCl3) δ7.44(s,2H),7.10(s,1H),2.32(s,6H),1.34(s,12H).ESI-MS, 233.2[M+H] +

[0041]

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Abstract

The invention provides a cesium neopentanoate co-catalyzed aryl borate preparation method, which comprises: dissolving a compound represented by a formula (I) and a diboron compound in an organic solvent, adding an organic solvent in which cesium neopentanoate, palladium acetate and triphenylphosphine are dissolved, and carrying out a reaction to obtain aryl borate, in the formula (I), R1, R2, R3, R4 and R5 being independently selected from H, C1-C10 alkyl, C2-C10 alkenyl, C2-C10 alkynyl, C1-C10 alkoxy, hydroxyl, hydroxyl-substituted C1-C10 alkyl, phenyl and C1-C10 alkylamino respectively; x being selected from F, Cl, Br and I. The preparation method is low in production cost, high in product yield and purity, easy to operate and suitable for industrial mass production.

Description

technical field [0001] The invention belongs to the technical field of chemical synthesis, and in particular relates to a preparation method of aryl borate catalyzed by cesium pivalate. Background technique [0002] Arylboronic ester compounds are a class of stable, low-toxic, important organic synthesis intermediates. Arylboronic acid esters overcome the disadvantages of difficult degradation and purification of arylboronic acid, poor storage stability, and easy deboration, and are widely used in transition metals. Catalyzed Suzuki–Miyaura cross-coupling reactions. Such compounds are widely used in the synthesis of fine chemicals, drugs, and pesticides, and are in great demand in the fields of organic synthesis, medicine, and materials. [0003] The traditional method of synthesizing aryl borates is metal catalyzed borylation reaction between halogenated aromatic hydrocarbons and boron reagents. Metal catalysis mostly uses catalysts such as palladium, copper, nickel, rhodi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07F5/02
CPCC07F5/025
Inventor 陈艳君杨伟群汪泠周家豪
Owner NINGBO POLYTECHNIC
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