Sulfuric Acid → 4-(trifluoromethyl)hepta-1,6-dien-4-ol

Participants

Reaction Steps

Allylmagnesium bromide was prepared from 140 g (1.16 mole) of allyl bromide, 35 g (1.44 mole) of magnesium and 640 ml of ether. The product was titrated and found to be 1.2 molar in allylmagnesium bromide. To a 230 ml (0.276 mole) aliquot of the reagent was added 17.4 g (0.122 mole) of ethyl trifluoroacetate in 60 ml of dry tetrahydrofuran at a drop rate of 2-3 drops/second. The reaction temperature was held near -40° during the addition. The reaction mixture was allowed to warm to room temperature and stirred overnight. It was heated at reflux for two hours, then stirred for an additional 24 hours. The reaction mixture was poured into 300 ml of ice and 20% sulfuric acid was added to bring the pH to about 1. The phases were separated and the aqueous phase extracted with 3×70 ml of ether. The combined organic phases were dried over magnesium sulfate, filtered and the solvent evaporated. The liquid product was distilled in vacuo to give 15.2 g (70%) of 4-hydroxy-4-trifluoromethyl-1,6-heptadiene, bp 54.5-58.5° C./30 torr.

Provenance & Evidence