Trimethyl borate → 3-Ethoxy-4-fluorobenzeneboronic acid

To a solution of 32A (3.86 g, 17.6 mmol) in THF (60 mL) at −78° C. was added n-BuLi (1.6 M in hexanes, 14.3 mL, 22.8 mmol). The mixture was stirred at −78° C. for 40 min before trimethyl borate (3.63 mL, 33 mmol) was added. The reaction was left stirring from −78° C. to rt over 4 h. It was quenched with 1.0 N HCl (40 mL), extracted with EtOAc, washed with brine and dried over Na2SO4. After evaporation of the solvent, the crude solid product was triturated with EtOAc/hexanes (1:4). After filtration, 32B (2.2 g, 69% yield) was collected as a white solid. 1H NMR (400 MHz, CDCl3) δ ppm 1.42 (t, J=7.03 Hz, 3H) 4.11 (q, J=7.03 Hz, 2H) 7.03 (dd, J=11.42, 8.35 Hz, 1H) 7.18-7.29 (m, 2H) 7.35 (d, J=7.91 Hz, 1H).

1. additionwas added
2. waitThe reaction was left
3. customIt was quenched with 1.0 N HCl (40 mL)
4. extractionextracted with EtOAc
5. washwashed with brine
6. dry with materialdried over Na2SO4
7. customAfter evaporation of the solvent
8. customthe crude solid product was triturated with EtOAc/hexanes (1:4)

ORD record

ord-0e0db7eb8ef14a7f84a3ccc379425190

Source dataset

uspto-grants-2009_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07622585B2