Diethyl Malonate → Diethyl (pentafluorobenzoyl)malonate

Participants

Reaction Steps

A 7.35 g portion of magnesium chips, 1.5 ml of carbon tetrachloride and 15 ml of absolute ethanol were added to a dry flask. A solution of 48.1 g of diethyl malonate in 30 ml of absolute ethanol and 120 ml of anhydrous ether was added dropwise over a one hour period. When addition was complete, the mixture was stirred at reflux for 3 hours then cooled to -10° C. with dry ice/acetone. A solution of 70 g of pentafluorobenzoyl chloride in 120 ml of ether was added over 2 hours, maintaining the temperature at not more than -5° C. The mixture was then stirred overnight at room temperature, partially evaporated, cooled in crushed ice and an ice cold solution of 7.5 ml of concentrated sulfuric acid in 300 ml of water was added at a rate such that the internal temperature did not go above 5° C. The mixture was extracted several times with ether, the extracts combined, washed with saturated sodium chloride, dried and concentrated, giving 106 g of (pentafluorobenzoyl)propanedioic acid, diethyl ester as a yellow oil.

Provenance & Evidence