Triethyl phosphonoacetate → Ethyl 5,5,5-trifluoropent-2-enoate

Participants

Reaction Conditions

Reaction Steps

To a stirred suspension of NaH (60% in oil, 2.15 g, 53.5 mmol) in dry THF (50 mL) was added dropwise ethyl(diethoxyphosphoryl)acetate (11 g, 49 mmol) at 0° C. under N2 atmosphere. The resulting mixture was stirred at 0° C. for 10 min and then cooled to −70° C. A solution of 3,3,3-trifluoropropanal (5.0 g, 44.5 mmol) in dry THF (50 mL) was added to the mixture at −70° C. After the addition, the stirred mixture was allowed to warm to −20° C. over 2 hrs. The reaction mixture was quenched by addition of 5% aqueous NH4Cl (100 mL) at 0° C. and extracted with EtOAc (100 mL). The organic layer was washed with brine (300 mL), dried over Na2SO4 and concentrated in vacuo. The residue was purified by column chromatography (silica gel, petroleum ether: EtOAc=100:1) to give the title compound (3.0 g, 37%) as a colorless oil.

Provenance & Evidence