Hexane → 5-(tert-Butyl)-2-methoxybenzeneboronic acid

Temperature

-78 °C

n-Butyllithium in hexane (2.5 M, 18.1 mL, 45.24 mmol) was added dropwise to a solution of 2-bromo-4-(tert-butyl)-1-methoxybenzene (10.0 g, 41.13 mmol) and triisopropyl borate (11.39 mL, 49.35 mmol) in tetrahydrofuran (90 mL) at −78° C. under nitrogen. The reaction mixture was stirred at −78° C. for 3 hours then allowed to warm slowly to 0° C. over 90 minutes. The reaction was then quenched by the addition of water (90 mL) and the tetrahydrofuran removed under reduced pressure. The resulting aqueous suspension was partitioned between diethyl ether (80 mL) and 1.0 M aqueous sodium hydroxide solution (100 mL). The aqueous phase was separated, cooled to 0° C. then acidified to pH 1 by the addition of concentrated hydrochloric acid. The resulting white suspension was stood at 0° C. for 15 minutes then filtered washing the solid product with water and cold hexane to give (5-(tert-butyl)-2-methoxyphenyl)boronic acid (6.349 g, 74% yield) as a white crystalline solid.

1. temperatureto warm slowly to 0° C. over 90 minutes
2. customThe reaction was then quenched by the addition of water (90 mL)
3. customthe tetrahydrofuran removed under reduced pressure
4. customThe resulting aqueous suspension was partitioned between diethyl ether (80 mL) and 1.0 M aqueous sodium hydroxide solution (100 mL)
5. customThe aqueous phase was separated
6. temperaturecooled to 0° C.
7. additionthen acidified to pH 1 by the addition of concentrated hydrochloric acid
8. waitThe resulting white suspension was stood at 0° C. for 15 minutes
9. filtrationthen filtered
10. washwashing the solid product with water and cold hexane

ORD record

ord-735f381b774e4f909e00eebf435d9c15

Source dataset

uspto-grants-2016_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09296696B2