Abstract: In this study, we developed a simple transition-metal-free borylation reaction of aryl bromides. Bis-boronic acid (BBA), was used, and the borylation reaction was performed using a simple procedure at a mild temperature. Under mild conditions, aryl bromides were converted to arylboronic acids directly without any deprotection steps and purified by conversion to trifluoroborate salts. The functional group tolerance was considerably high. The mechanism study suggested that this borylation reaction proceeds via a radical pathway.
* All experimental methods are cited from the reference, please refer to the original source for details. We do not guarantee the accuracy of the content in the reference.
With palladium 10% on activated carbon; potassium acetate; bis(pinacol)diborane; In ethanol; at 60℃; for 8h;Inert atmosphere;
General procedure: To a solution of brominated aromatic compounds (1 equiv),bis(pinacolate)diboron (1.5 equiv) and anhydrous ethanol (15 mL)were added10%palladium-carbon (0.01 equiv), followed by potassium acetate (3 equiv) under argon. The mixture was heated in a 60 C with stirring for the indicated time. Thereactor was cooled to room temperature, and the reaction mixture was filtered, and thefiltrate was concentrated under reduced pressure. The residue was extracted with dichloromethane (20 mL×3), and organic layer was washed with water (20 mL×2)and once with brine (25 mL), dried over magnesium sulfate and concentrated in vacuo.The product was purified by silica gel flash chromatography on silica gel usingpetroleum as eluent.
With potassium phosphate tribasic hydrate; NiIICl(1-naphthyl)(tricyclohexylphosphine)2; tricyclohexylphosphine; In tetrahydrofuran; at 23℃; for 20h;Inert atmosphere; Glovebox; Sealed tube;
General procedure: Cross-Coupling of ortho-, meta-, and para-Substituted, Electron-Rich and Electron-Deficient Aryl Halides and Aryl Mesylates with Aryl Neopentylglycolboronates Catalyzed by NiIICl(1-naph-thyl)(PCy3)2/PCy3 in Anhydrous THF at 23 °C; General Procedure 2In an oven-dried test tube charged with a Teflon coated stirring barwere added aryl halide or aryl mesylate (0.3 mmol), aryl neopentyl-glycolboronates (0.315 mmol), K3PO4(H2O)3.2 (191.00 ± 1.00 mg, 0.9mmol), and NiIICl(1-naphthyl)(PCy3)2 (11.73 ± 0.0510 mg, 0.015mmol, 5percent catalyst loading). The test tube was brought into a N2 filledglove box (moisture level <2 ppm) through three degassing cycles andPCy3 (8.4 mg, 0.03 mmol, 10percent loading) ligand was added. Distilled sol-vent (1 mL) was added inside the glove box and the test tube wassealed by a rubber septum and left stirring at 23 °C. A sample was tak-en by syringe and transferred outside the glove box. The sample wasdiluted by distilled THF (0.2 mL) and filtered through a short columnof Al2O3. The filtrate was concentrated and the GC analysis was car-ried out. The reaction mixture was diluted with CH2Cl2 (2 mL), filteredthrough a layer of Al2O3, and washed with CH2Cl2 (3 1 mL). The fil-trate was collected and concentrated under vacuum. The crude prod-uct was purified by column chromatography on silica gel with EtO-Ac/hexane mixture as eluent. The reductive elimination side-productwas also isolated and characterized.
2',3,3',4-tetramethoxy[1,1':4',1"-terphenyl]-4"-carboxylic acid[ No CAS ]
[ 108840-32-0 ]
Yield
Reaction Conditions
Operation in experiment
29.7%; 21.1%; 10.4%
General procedure: The appropriate bromo derivatives (1 eq.), appropriate phenyl boronic acids (1.5 eq.) and KF*2H2O (3.0 eq.) were dissolved in dioxane and the three resulting mixtures were deoxygenated with a stream of N2. After 10 min, PdCl2(dppf) (0.05 eq.) was added, and each mixture was brought to reflux and stirred under N2 for 5-22 h until the reaction was complete, followed by detection using TLC. Then, each solution was cooled to room temperature. Next, each solution was poured into a mixture of H2O and ethyl acetate, and the two phases were separated. The aqueous layer was washed with ethyl acetate, and the organic phases were combined and washed with brine. The ethyl acetate layer was dried over anhydrous sodium sulfate and evaporated to dryness under reduced pressure. Each crude product was purified via chromatography or Sephadex LH-20.
Chemistry
Pharmaceutical Intermediates
Inhibitors/Agonists
Material Science
For Research Only
120K+ Compounds
Competitive Price
1-2 Day Shipping
