(Carbomethoxymethyl)triphenylphosphonium bromide

96-32-2

603-35-0

1779-58-4

To a stirred ethyl acetate solution of triphenylphosphine (1.7 g, 6.7 mmol), an ethyl acetate solution of methyl 2-bromoacetate (0.62 μL, 6.5 mmol) was slowly added at room temperature. The reaction mixture was stirred at room temperature for 17 h to produce a white precipitate. The precipitate was collected by filtration and washed three times with ether, followed by drying in air to afford (2-methoxy-2-oxoethyl)triphenylphosphonium bromide (4, 2.49 g) as a white solid in near quantitative yield. The resulting phosphonium bromide 4 (2.0 g, 4.81 mmol) was added to an ethanol (10 mL) suspension of sodium ethanolate (340 mg), followed by the slow addition of 3a (1.15 g, 4.75 mmol) over a period of 25 min at room temperature. The reaction mixture was stirred at 50-55 °C for 1 h, during which the progress of the reaction was monitored by TLC. Upon completion of the reaction, water (10 mL) was added to the reaction mixture and the product was extracted four times with ether (20 mL). The organic layers were combined, dried with anhydrous sodium sulfate and evaporated under reduced pressure to remove the solvent to give a solid residue. Further purification by column chromatography (eluent: ethyl acetate/hexane, 3:7) afforded a 3.5:1 mixture of E- and Z-cinnamic acid methyl ester derivatives.