Trifluoromethanesulfonic acid → 5,7-Difluorochroman-4-one

Participants

Reaction Conditions

Reaction Steps

A mixture of methyl 3-(3,5-difluorophenoxy)propanoate (11.6 g, 53.7 mmol, STEP 6) and trifluoromethanesulfonic acid (23.2 mL, 2.0 mL/g of substrate) was stirred at 80° C. for 2 hours. After cooling to room temperature, the reaction mixture was diluted with water (120 mL), and extracted with toluene (120 mL). The organic layer was washed successively with aqueous solution of potassium carbonate (50 mL), water (50 mL), and dried over magnesium sulfate. The organic mixture was concentrated in vacuum to afford the title compound (8.75 g, 88%) as a white solid, which was used in the next step without further purification.

Provenance & Evidence