A solution was prepared in DMF (75 mL) with sodium chlorodifluoroacetate (12.48 g, 82 mmol) and m-hydroxybenzaldehyde (5.00 g, 40.9 mmol). The solution was added dropwise to a solution of DMF (25 mL) containing potassium carbonate (8.49 g, 61.4 mmol) over a period of 3 hours, and the reaction temperature was maintained at 95 °C. After the dropwise addition, the reaction continued to be stirred at 95 °C for 2 hours. After completion of the reaction, the reaction mixture was cooled to room temperature. The reaction mixture was diluted with deionized water (100 mL) and subsequently extracted with ethyl acetate (4 x 50 mL). The organic phases were combined, washed with 10% (w/v) aqueous lithium chloride (3 x 25 mL), dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure to give the crude product. Purification by fast column chromatography (eluent: 15% ethyl acetate/hexane) afforded 3-(difluoromethoxy)benzaldehyde (2.50 g, 14.52 mmol, 36% yield) as a yellow oil. The nuclear magnetic resonance (NMR) spectrum of the product was consistent with the expected structure.
