Triethylamine → (E)-3-(2,4-dichlorophenyl)prop-2-enal

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Reaction Conditions

Reaction Steps

3-(2,4-Dichlorophenyl)acrylic acid (900 mg, 4.15 mmol) is dissolved in tetrahydrofuran (50 mL) and the resulting solution is cooled to 0° C. before triethylamine (0.692 mL, 4.98 mmol) and isobutyl chloroformate (0.647 mL, 4.98 mmol) are added. The reaction mixture is stirred for 30 min and the precipitate formed is filtered off. The filtrate is then cooled to 0° C. and water (1 mL) is added followed by sodium borohydride (314 mg, 8.29 mmol). The resulting mixture is stirred for 30 min until complete conversion is observed. The solution is diluted with ethyl acetate (100 mL) and the organic layer is washed with aqueous 1M hydrochloride (30 mL) and with brine (30 mL), is dried over sodium sulphate and is concentrated under reduced pressure after filtration. The residue obtained is dissolved in dichloromethane (20 mL) and Dess-Martin periodinane (2638 mg, 6.22 mmol) is added. The solution is stirred at room temperature for 3 h until full conversion of the starting material is observed. The reaction mixture is washed with a 1 to 1 solution of aqueous 10% sodium thiosulphate and of aqueous saturated sodium hydrogen carbonate (10 mL) and with brine (10 mL). The organic layer is dried over sodium sulphate, filtered and concentrated under reduced pressure. The crude product isolated is finally purified by flash column chromatography on silica gel (dichloromethane as eluent) to give the desired product (624 mg, 3.10 mmol, 75% yield).

Provenance & Evidence