Triethylamine → Methyl 2-(3,5-difluoro-4-(trifluoromethylsulfonyloxy)phenyl)acetate

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Reaction Conditions

Reaction Steps

Trifluoromethanesulphonic anhydride (0.854 mL, 5.21 mmol) was added dropwise to a stirred solution of methyl 2-(3,5-difluoro-4-hydroxyphenyl)acetate (Intermediate 24-3; 0.702 g, 3.47 mmol) in DCM (15.06 mL) cooled to 0° C., over a period of 5 minutes under nitrogen. Triethylamine (1.452 mL, 10.42 mmol) was added dropwise over 5 minutes (keeping internal temperature between 5-10° C.) and the resulting solution stirred at room temperature for 4 hours under nitrogen. The reaction mixture was diluted with DCM (100 mL), and washed sequentially with water (100 mL), saturated NaHCO3 (100 mL), and water (100 mL). The organic layer was dried by passing through a phase seperating cartridge and evaporated to afford crude product. The crude product was purified by flash silica chromatography, elution gradient 0 to 20% EtOAc in isohexane. Pure fractions were evaporated to dryness to afford methyl 2-(3,5-difluoro-4-(trifluoromethylsulfonyloxy)phenyl)acetate (0.930 g, 80%) as a straw yellow oil.

Provenance & Evidence