Hydrochloric Acid → (2,6-Diethylphenyl)boronic acid

Temperature

-75 °C

2,6-Diethyl bromobenzene (38.2 g, 180.2 mmol) is added dropwise through an additional funnel over a 1 h period to a solution of n-BuLi (2.0 M in cyclohexane, 99.1 mL, 198.2 mmol) in THF (380 mL) at −75° C. After addition, the reaction mixture is stirred at −75° C. for 30 min; trimethyl borate (28.1 g, 270.3 mmol) is added slowly over a 40 minute period. The reaction mixture is warmed to room temperature overnight. 2N HCl (250 mL) is added slowly and the resulting mixture is stirred for 1 h. The organic layer is separated and the aqueous layer is extracted with ether (2×200 mL). The combined organic layers are dried over anhydrous Na2SO4 and the solvents are removed in vacuo. Hexane (400 mL) is added to the residue and a white precipitate is formed. Filtration and drying in vacuo give 2,6-diethylphenyl boronic acid as a white solid. 1H NMR: (CDCl3) 7.22 (t, 1H), 7.04 (s, 2H), 4.65 (s, 2H), 2.64 (q, 4H), 1.22 (t, 6H).

1. additionAfter addition
2. temperatureThe reaction mixture is warmed to room temperature overnight
3. stirringthe resulting mixture is stirred for 1 h
4. customThe organic layer is separated
5. extractionthe aqueous layer is extracted with ether (2×200 mL)
6. dry with materialThe combined organic layers are dried over anhydrous Na2SO4
7. customthe solvents are removed in vacuo
8. additionHexane (400 mL) is added to the residue
9. customa white precipitate is formed
10. filtrationFiltration
11. customdrying in vacuo

ORD record

ord-db3d5a693bc64918adeab23d21bd476c

Source dataset

uspto-grants-2012_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08338591B2