Hydrochloric Acid → 3,3-Dimethyl-1,3-dihydro-2,1-benzoxaborol-1-ol

Temperature

-78 °C

To a solution of 2-(2-bromo-phenyl)-propan-2-ol (4.0 g, 18.6 mmol, prepared as described in Egan, W. et al. J. Am. Chem. Soc., 1971, 93, 6205) in 60 mL of anhydrous THF under argon at −78° C. was slowly added n-butyl lithium (15 mL, 2.5 M). The mixture was stirred at −78° C. for 2 h, and then triisopropylborate (5.5 mL, 24.2 mmol) was added to the mixture. The mixture was allowed to warm to room temperature and stirred at room temperature for 12 h. The mixture was then cooled to 0° C. and hydrochloric acid (10 mL, 1N) was added to the mixture until pH was <5. The mixture was then stirred at room temperature for 1 h. The two layers were separated. The aqueous layer was extracted twice with ethyl acetate. The organic layers were combined, dried with anhydrous sodium sulfate and filtered. The filtrate was concentrated under reduced pressure to afford a yellow oil. The oil was purified by chromatography (silica, EtOAc: hexanes,1:3) to afford a white solid (1.16 g, 40%). 1H NMR (400 MHz, CDCl3) δ (ppm): 7.53 (m, 1H), 7.36 (m, 2H), 7.28 (m, 1H), 1.62 (s, 3H), 1.61 (s, 3H).

1. customat −78° C.
2. temperatureto warm to room temperature
3. stirringstirred at room temperature for 12 h
4. temperatureThe mixture was then cooled to 0° C.
5. stirringThe mixture was then stirred at room temperature for 1 h
6. customThe two layers were separated
7. extractionThe aqueous layer was extracted twice with ethyl acetate
8. dry with materialdried with anhydrous sodium sulfate
9. filtrationfiltered
10. concentrationThe filtrate was concentrated under reduced pressure
11. customto afford a yellow oil
12. customThe oil was purified by chromatography (silica, EtOAc: hexanes,1:3)

ORD record

ord-3eef604f9dc2429c89537ee8f7a941a0

Source dataset

uspto-grants-2009_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07612211B2