Triisopropyl borate → (4-Chloro-3-ethoxyphenyl)boronic acid

Participants

Reaction Steps

To a solution of 31A (3.8 g, 16 mmol) in THF (20 mL) at −78° C. was added n-BuLi (1.6 M in hexanes, 13.6 mL, 21.8 mmol). The mixture was stirred at −78° C. for 40 min before triisopropyl borate (7.43 mL, 32 mmol) was added. The reaction was left stirring, from −78° C. to rt over 18 h. It was quenched with 1.0 N HCl (50 mL), extracted with EtOAc, washed with brine and dried over Na2SO4. The crude residue was purified by flash column chromatography (CH2Cl2: EtOAc: MeOH=50:50:1) to give 1.85 g (57%) of 31B as a white solid. 1H NMR (400 MHz, CDCl3) δ ppm 1.53 (t, J=7.03 Hz, 3H) 4.23 (d, J=7.03 Hz, 2H) 7.48 (d, J=7.91 Hz, 1H) 7.66 (d, J=6.15 Hz, 2H).

Provenance & Evidence