METHYL 2-(4,4,5,5-TETRAMETHYL-1,3,2-DIOXABOROLAN-2-YL)BENZOATE

White powder

Under nitrogen protection, Methyl o-bromobenzoate (2.15 g, 10 mmol), bis(pinacolato)diboron(3.05g, 12mmol), Potassium acetate (3.92 g, 40 mmol), [1, 1'-bis(diphenylphosphino)ferrocene]palladium dichloride (0.49 g, 0.5 mmol)It was added to 150 mL of dioxane and heated to 85 ° C for 12 hours.After the completion of the reaction, the dioxane was removed by distillation under reduced pressure, and the product was extracted with dichloromethane.Washed three times with saturated aqueous sodium chloride solution, After distilling off the dichloromethane under reduced pressure, The crude product was purified by column chromatography eluting with petroleum ether: methylene chloride = 3:1 (v/v) to give a solid, 2.25 g, yield 86percent.The results of 1H NMR, 13C NMR, MS and elemental analysis indicated that the obtained compound was the object product.The dried 2 L reactor under nitrogen to 2-bromo-ethyl acetate 100 g (0.465 mol), bis(pinacolato)diboron 177.1 g (0.698 mol), [1, 1 '- bis (diphenylphosphino) ferrocene ] dichloropalladium put 10.2 g (14 mmol), potassium acetate 136.9 g (1.395 mol) and 1000 mL of toluene was refluxed for 12 hours. Then filtered hot, the filtrate was concentrated under reduced pressure, and then separated by column chromatography to give the compound 96 g (yield: 84.9percent) represented by the [intermediate 7-c].2-bromoethyl acetate in 2L reactor 100 g (465 mmol), bis (pinacolato Collet Sat) dieboronic 177.1 g (698mmol), [1, 1'- bis (diphenylphosphino) ferrocene]dichloropalladium 10.2 g put (14 mmol), potassium acetate 136.9 g (1395 mmol) and1000 mL of toluene was refluxed for 12 hours. Then filtered hot, the filtrate wasconcentrated under reduced pressure, and then separated by column chromatography togive the compound 96 g (yield: 78.8percent).Intermediate 1-d was synthesized according to Reaction Scheme 4 below.To a 500 mL round bottom flask reactor was added 2-bromo-methylbenzoate (14 g, 65 mmol), bispinacolatodiboron (10.4 g, 41 mmol), palladium (II) Diphenylphosphino) ferrocene (1.4 g, 1 mmol), potassium acetate (6.7 g, 68 mmol) and toluene (140 ml) were added and the mixture was refluxed with stirring for 10 hours. After completion of the reaction, the solid is filtered off and the filtrate is concentrated under reduced pressure. Separation by column chromatography gave intermediate 1-d. (10.5 g, 62percent).In 5 mL of anhydrous DMF was added B3a (150 mg, 0.5 mmol), PdClTo a reaction tube equipped with a magnetic stir bar was added the catalyst palladium acetate (4.5 mg, 0.02 mmol), potassium carbonate (69.0 mg, 0.5 mmol), norbornene (37.6mg, 0.4mmol), 10.8 g (19 mmol) of [Formula 13-e] in a 250 ml round bottom flask, 6.4 g (24 mmol) of methyl 2- (4, 4, 5, 5, -tetramethyl-1, 3, 2-dioxaborolyl) benzoate, 0.4 g (1 mmol) of tetrakis (triphenylphosphine) palladium (0), 7.8 g (56 mmol) of potassium carbonate, 54 ml of 1, 4-dioxane, Toluene 54ml, 21 ml of water was added thereto, and the mixture was refluxed and stirred. After confirming the TLC, the reaction was terminated, cooled to room temperature, extracted with ethyl acetate / water, the organic layer was separated and concentrated under reduced pressure, and the concentrate was separated by a column.The separated solution was concentrated under reduced pressure and recrystallized with methylene chloride / hexane to give 7.9 g (yield: 66.7%) of the compound represented by [Formula 13-f].Compound 16C (1 g, 1.0 eq), 16D (1.27 g, 1.1 eq) were dissolved in 20 mL 1, 4-dioxane, then added 2M K2C03 in water (3 mL). The mixture was flushed with N2, then added PdCl2(dppf)CH2Cl2 (0.33 g, 0.1 eq). The resulting mixture was heated at 90C for 2hrs in a sealed-tube. The reaction mixture was diluted with 100 mL ethyl acetate, washed with water and brine. The crude mixture was directly purified on ISCO silica gel column to provide 16E (1.06g, yield 85%).

Molecular Weight:262.11
Hydrogen Bond Acceptor Count:4
Rotatable Bond Count:3
Exact Mass:262.1376392
Monoisotopic Mass:262.1376392
Topological Polar Surface Area:44.8
Heavy Atom Count:19
Complexity:337
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes