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Synthesis method of alkenyl borate compound

A kind of technology of alkenyl borate ester and synthesis method, applied in the field of organic synthesis, achieves the effects of high yield, low content of harmful metals, easy and safe operation

Pending Publication Date: 2022-03-11
HEFEI UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0016] Aiming at the shortcomings of the existing synthetic routes, the present invention provides a method for synthesizing alkenyl borate compounds, which can catalyze the hydroboration reaction of alkynes by using low-loaded palladium content, and does not require a high-temperature environment, and has the advantages of easy-to-obtain raw materials , simple process, mild conditions, relatively high yield, wide range of substrates, relatively few by-products, etc.

Method used

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  • Synthesis method of alkenyl borate compound
  • Synthesis method of alkenyl borate compound
  • Synthesis method of alkenyl borate compound

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035]

[0036] Put neopentylglycol diboronate (0.30mmol, 1.5equiv) and 4-dimethylaminopyridine (0.60mmol, 3.0equiv) into a transparent Schlenk tube equipped with a stirring bar, vacuumize the tube, and then blow in argon Air, repeat 3-4 times. Add biphenylacetylene (1a) (0.20mmol, 1.0equiv), Pd(PCy 3 ) 2 Cl 2 (400ppm) and solvent (ethanol, 3mL), the reaction mixture was stirred at 70°C for 10 hours; after the reaction was completed, it was cooled to room temperature, quenched with water and extracted with ethyl acetate, the organic layers were combined, dried over sodium sulfate, and then concentrated in vacuo , the product was purified by silica gel flash column chromatography (petroleum ether / ethyl acetate=20:1) to give colorless oil (2a) (44mg, 75%). The NMR data of this compound are: 1 H NMR (600MHz, CDCl 3 ) δ7.59(d, J=8.1Hz, 2H), 7.56(d, J=2.6Hz, 3H), 7.43(t, J=7.7Hz, 2H), 7.37(d, J=18.3Hz, 1H) ,7.33(t,J=7.4Hz,1H),6.14(d,J=18.3Hz,1H),3.71(s,4H),1.01(s,6H). 13 ...

Embodiment 2

[0038]

[0039] Table 1 Low-concentration metal-catalyzed hydroboration of alkynes

[0040]

[0041]

[0042] For the above reaction, we used 4-ethynyl-1,1'-biphenyl (1) and neopentyl glycol diboronate (2) as model substrates, o-xylene as solvent, and potassium acetate as base. A suitable metal catalyst concentration of 400ppm is used to realize the hydroboration reaction of alkynes. Attempts to start cheap metals, 400ppm (0.04mol%) nickel chloride, or its combination with various phosphine ligands (PPh 3 ,PCy 3 , Xantphos) can also provide a lower yield of the target product, but more by-products. The combination of 400ppm (0.04mol%) cuprous chloride and phenanthroline ligand (1,10-Ph, NC) cannot provide the target product, and the combination of 400ppm (0.04mol%) cuprous chloride and phosphine ligand (PPh 3 ,PCy 3 , Sphos, Xphos, 5mol%) can provide a lower yield of the target product, but the reaction is more complicated. Excitingly, 400ppm of Pd(PCy 3 ) 2 Cl...

Embodiment 3

[0044]

[0045] The optimization of the base of table 2 alkyne hydroboration

[0046] Entry Base Yield(%) b

[0047] After screening for suitable catalysts, bases were screened. Three equivalents of sodium acetate provided 50% of the target product. Sodium carbonate, potassium carbonate, cesium carbonate can provide the target product (25%, 30%, 15%) of lower yield, potassium hydroxide can provide 33% target product, and sodium hydroxide can not provide target product either. Organic bases were also investigated, with triethylamine providing 22% of the target product and 1,8-diazabicyclo[5.4.0]undec-7-ene providing 55% of the target product. Triethylenediamine can provide 10% of the target product, and 4-dimethylaminopyridine has the best effect, which can provide 65% of the target product.

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Abstract

The invention discloses a synthesis method of an alkenyl borate compound, which comprises the following steps: by taking a phenylacetylene compound as a raw material, carrying out selective C-H bond boronation reaction on phenylacetylene hydrocarbon in the presence of a catalyst, a boron reagent and alkali to obtain a trans-olefin borate compound with high selectivity. The method has the advantages of high efficiency, mild reaction conditions, convenience in operation, relatively short reaction time, relatively few byproducts and the like, and is suitable for large-scale production.

Description

technical field [0001] The invention relates to a method for synthesizing an alkenyl borate compound. Trans-alkene borate compounds are synthesized by selectively borating the C-H bond of phenylacetylene compounds, which belongs to the field of organic synthesis. Background technique [0002] Alkenyl boronic esters are highly versatile building blocks in organic synthesis because of their wide-ranging applications in the construction of C-C bonds and C-heteroatom bonds, which are commonly found in drug design, synthesis of bioactive molecules, and functional materials. [0003] Hydroboration of alkynes is a straightforward method for the synthesis of these boronate compounds. However, copper-catalyzed reactions of alkynes with diboronic acid pinacol or other processes often yield β-vinyl(pinacol)boron. Preparation methods for other types of vinyl borates, such as β-vinyl(neopentyl glycolate)boron, are relatively limited and generally require multi-step transformations. Due...

Claims

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Application Information

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IPC IPC(8): C07F5/02
CPCC07F5/025
Inventor 张彪许华建徐俊
Owner HEFEI UNIV OF TECH
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