Triisopropyl borate → [2-Fluoro-6-(2-methoxyethoxy)pyridin-3-yl]boronic acid

Participants

Reaction Conditions

Reaction Steps

2-Fluoro-6-(2-methoxyethoxy)pyridine (1.13 g, 6.60 mmol) in THF (5 mL) was cooled to −60° C. and treated with lithium diisopropylamide, 2.0 M solution in heptane/tetrahydrofuran/ethylbenzene (4.95 mL, 9.90 mmol) (Aldrich) and stirred at −60° C. for 1 h. The mixture was then treated with triisopropyl borate (2.277 mL, 9.90 mmol) (Aldrich) and allowed to warm to RT over 30 min. It was then quenched by the addition of a saturated solution of ammonium chloride and stirred for 30 min. The reaction mixture was extracted with EtOAc (3×25 mL), dried over MgSO4, filtered and concentrated. Purification on the ISCO (12 g column, 5-100% EtOAc) gave a mixture of 2-fluoro-6-(2-methoxyethoxy)pyridin-3-ylboronic acid (226 mg, 1.051 mmol, 15.92% yield) and 6-fluoro-2-(2-methoxyethoxy)pyridin-3-ylboronic acid as a semi-crystalline solid. m/z (ESI, +ve ion) 216.1 (M+H)+.

Provenance & Evidence