Tetrahydrofuran → 2-Chloro-5-methoxypyridine-3-boronic acid

Participants

Reaction Steps

2.5 M n-BuLi in hexane (3.7 mL, 9.3 mmol) was added slowly to a stirred premixed solution of 3-bromo-2-chloro-5-methoxypyridine (1.73 g, 7.8 mmol) and triisopropyl borate (2.1 mL, 9.3 mmol) in THF (10.0 mL, 122 mmol) at −78° C., and the resulting deep colored mixture was stirred at the same temperature for 1 h and then allowed to warm up to room temperature over 1 h. The reaction was quenched with 1 N NaOH(aq) and then some EtOAc. The separated aqueous layer was acidified with 5N HCl until pH about 5 and then extracted with EtOAc(×2) and the combined organic layers were washed with brine, dried over Na2SO4, and concentrated to give 2-chloro-5-methoxypyridin-3-ylboronic acid (1.0276 g, 71%) as a brown solid. LCMS (API-ES) m/z 188 (M+H)+.

Provenance & Evidence