Triisopropyl borate → (6-Methoxypyridin-3-yl)boronic acid

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Reaction Steps

To 5-bromo-2-methoxypyridine (8.25 g, 43.9 mmol) and triisopropylborate (10.3 g, 55.0 mmol) in THF (110 mL) at −80° C. was dropwise added n-BuLi (1.6M in hexanes, 30.1 mL, 48.2 mmol). The reaction mixture was gradually warmed to RT over 1 h and then stirred at RT for 16 h. The reaction mixture was quenched by addition of 1N aqueous HCl solution and stirred for 1 h. The aqueous layer was basified with 6N aqueous NaOH to pH=9, extracted with a mixture of EtOAc and Et2O. The aqueous layer was acidified to pH=7 and extracted with EtOAc. The combined organic layers were dried over Na2SO4, filtered and concentrated in vacuo. This material was used in the next step without further purification.

Provenance & Evidence