Triisopropyl borate → {4-[4-(Trifluoromethoxy)phenoxy]phenyl}boronic acid

Participants

Reaction Conditions

Reaction Steps

To a solution of 1-bromo-4-(4-(trifluoromethoxy)phenoxy)benzene (5.07 g, 15.2 mmol) in THF (76 ml) at −78° C. was added n-butyl lithium (7.6 ml, 2.5 M in hexanes, 19.0 mmol) dropwise. The reaction mixture was stirred 0.5 hours at −78° C., and triisopropylborate (7.0 ml, 30.4 mmol) was added. The reaction was stirred 4 hours at room temperature, quenched with 1 N HCl and stirred 0.5 hours at 0° C. The aqueous layer was extracted with ethyl acetate. The combined organic layers were extracted with brine and dried over magnesium sulfate. Purification by silica gel chromatography (0-10% methanol in dichloromethane) provided 4.38 g (4-(4-(trifluoromethoxy)phenoxy)phenyl)boronic acid (97% yield) as a light brown viscous oil. 1H NMR (400 MHz, CDCl3) δ 8.20 (d, J=8.9 Hz, 1H), 7.26 (d, J=8.9 Hz, 1H), 7.07-7.14 (m, 2H).

Provenance & Evidence