Boron tribromide → Diethyl 2-(2,6-difluoro-4-hydroxyphenyl)malonate

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Reaction Conditions

Reaction Steps

To a solution of diethyl 2-(2,6-difluoro-4-methoxyphenyl)malonate (2.11 g, 7.0 mmol) in 60 mL of methylene chloride at −78° C. is added boron tribromide (2.65 mL, 28 mmol) dropwise. The mixture is then stirred at −78° C. for 10 minutes, warmed to 0° C., and stirred at 0° C. for 1 h. A 5% aqueous solution of sodium bicarbonate is added slowly to quench the reaction. The product is extracted with ethyl acetate. The combined organic extracts are washed with saturated sodium chloride, dried over magnesium sulfate, and concentrated to a residue. The residue is chromatographed over silica gel, eluting with a gradient of 10% ethyl acetate in hexanes to 30% ethyl acetate in hexanes. Concentration provides diethyl 2-(2,6-difluoro-4-hydroxyphenyl)malonate as a colorless oil (1.91 g). MS: m/z 287.2 (M−H).

Provenance & Evidence