Hexane → [5-(Trifluoromethyl)pyridin-3-yl]boronic acid

Participants

Reaction Conditions

Reaction Steps

To a solution of 3-bromo-5-(trifluoromethyl)pyridine (2.5 g, 11.06 mmol) and triisopropylborate (3.06 mL, 13.27 mmol) in anhydrous tetrahydrofuran (20 mL) at −78° C. under nitrogen was added dropwise a solution of n-butyl lithium in hexane (2.5 M, 4.9 mL, 12.17 mmol) The reaction was stirred at −78° C. for 3 hours then allowed to warm slowly to −10° C. The reaction mixture was then quenched by the addition of water (20 mL) and the tetrahydrofuran removed under reduced pressure. The resulting aqueous phase was diluted with water (40 mL) and washed with ether (2×40 mL). The aqueous phase was then acidified to pH 5 by the addition of acetic acid and the resulting suspension extracted with ethyl acetate (80 mL). The organic phase was separated, dried (MgSO4), filtered and concentrated under reduced pressure to give 3-(trifluoromethyl)pyridine-5-boronic acid (2.022 g, 96% yield) as a tan solid.

Provenance & Evidence