Hydrochloric Acid → 3-Benzyloxy-phenylboronic acid

To a −78° C. mixture of 3-benzyloxobromobenzene (0.590 g, 2.24 mmol, 1 equiv) in THF (10 mL) was added n-butyllithium (1.6 M in hexanes, 2.9 mL, 4.7 mmol, 2.1 equiv). The reaction mixture was stirred for 45 min and then triisopropylborate (0.77 mL, 3.4 mmol, 1.5 equiv) was added. The reaction mixture was stirred at −78° C. for 30 min and was allowed to warm to ambient temperature over 2 h. Hydrochloric acid (2.5M, 10 mL) was added and the mixture was stirred vigorously for 16 h. The organic portion was separated and the aqueous layer was extracted with two portions of Et2O (50 mL each). The combined organic extracts were dried over MgSO4, filtered, and concentrated to afford a brown oil. The residue was triturated from heptane (100 mL) and the precipitate was collected by filtration to afford 3-(benzyloxy)phenylboronic acid as a lavendar solid (0.111 g, 0.486 mmol): 1H NMR (d6 DMSO, 400 MHz): δ H 8.00 (2H, bs), 7.02-7.46 (9H, m), and 5.09 (2H, s).

1. stirringThe reaction mixture was stirred at −78° C. for 30 min
2. stirringthe mixture was stirred vigorously for 16 h
3. customThe organic portion was separated
4. extractionthe aqueous layer was extracted with two portions of Et2O (50 mL each)
5. dry with materialThe combined organic extracts were dried over MgSO4
6. filtrationfiltered
7. concentrationconcentrated
8. customto afford a brown oil
9. customThe residue was triturated from heptane (100 mL)
10. filtrationthe precipitate was collected by filtration

ORD record

ord-2badd73165e046269b795d2b49b5fa1f

Source dataset

uspto-grants-2003_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06660744B1