Trimethyl borate → 3,3-bis(fluoromethyl)-5-methylbenzo[c][1,2]oxaborol-1(3H)-ol

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Reaction Steps

To a solution of 1-bromo-2-(2-(ethoxymethoxy)-1,3-difluoropropan-2-yl)-4-methylbenzene (1.8 g, 5.10 mmol) in THF (15 mL) at −78° C. was slowly added n-BuLi (5.1 mL, 12.75 mmol). After stirring for 10 min, a solution of B(OMe)3 (1.06 g, 10.2 mmol) in dry THF (5 mL) was added dropwise. The mixture was stirred at −78° C. for 0.5 h, and then dry ice bath was removed. The solution was acidified with HCl (4 N) and extracted with EA (100 mL×2). The combined organic layers were washed with brine, dried over Na2SO4, filtered and concentrated under reduced pressure. The residue was purified by column chromatography over silica gel eluted with PE:EA (5:1 to 3:1) to give the desired compound (350 mg, yield 32%) as white solid.

Provenance & Evidence