Triethyl phosphonoacetate → (2E)-3-(2,6-Difluoro-4-methoxyphenyl)-2-propenoic Acid Ethyl Ester

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Reaction Steps

A solution of ethyl diethylphosphonoacetate (2.34 g, 10.4 mmol) and sodium hydride (60% in oil, 0.38 g, 9.50 mmol) in tetrahydrofuran (40 mL) was stirred under ice-cooling for 10 min. 2,6-Difluoro-4-methoxybenzaldehyde (1.5 g, 8.71 mmol) was added to the solution, and the mixture was stirred for 4 hr while raising the temperature to room temperature. The reaction mixture was diluted with ethyl acetate, and the mixture washed successively with aqueous citric acid solution, water and aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. The residue was subjected to silica gel column chromatography (ethyl acetate:hexane=1:10-1:5) to give the title compound (1.1 g, yield 52%) as colorless needle crystals. MS: m/z 243 (MH+).

Provenance & Evidence