Dimethylformamide → 5-Bromo-8-difluoromethoxy-2H-chromen-2-spiro-1'-cyclobutane

Participants

Reaction Conditions

Reaction Steps

To 48 ml of N,N-dimethylformamide solution containing 10.0 g (27.5 mmol) of 3-bromo-6-difluoromethoxy-2-iodophenol obtained in Reference example 12-(f) were added 0.62 g (2.8 mmol) of palladium acetate, 9.2 g (110 mmol) of sodium hydrogencarbonate and 3.23 g (32.9 mmol) of 1-vinylcyclobutanol (see J. Org. Chem., 1977, 42, 300-305) under argon atmosphere, and the mixture was stirred at 140° C. for 4 hours. After completion of the reaction, water was added to the reaction mixture, and the mixture was extracted with toluene. The organic layer after separation was washed with a saturated aqueous solution of sodium chloride, dried over anhydrous sodium sulfate and then concentrated under reduced pressure. The obtained residue was applied to silica gel column chromatography (Eluent; hexane:ethyl acetate=9:1 (V/V)), and the fractions containing the desired compound were concentrated under reduced pressure to obtain 0.61 g of the title compound as a pale yellowish oil. (Yield: 70%)

Provenance & Evidence