Ethanone, 1-cyclopentyl-2,2,2-trifluoro- (9CI) synthesis

Yield:-

Reaction Conditions:

with hydrogenchloride;iodine;magnesium;trifluoroacetic acid in tetrahydrofuran;diethyl ether;water

Steps:

5 STAGE A: Cyclopentyl trifluoromethyl ketone
STAGE A: Cyclopentyl trifluoromethyl ketone A suspension of sodium trifluoroacetate, prepared by adding 0.5 mol of trifluoroacetic acid dissolved in THF slowly at 0° C. to 0.5 mol of sodium hydride suspended in THF, is added to an organomagnesium reagent, itself prepared by the dropwise addition under continuous reflux of 0.5 mol of cyclopentyl bromide dissolved in 400 ml of ethyl ether to 13.4 g of magnesium turnings placed in 50 ml of anhydrous ethyl ether with an iodine crystal, refluxing being maintained for one hour. The white suspension thereby obtained is brought to reflux for 2 hours 30 minutes and kept overnight at room temperature. The mixture is then hydrolyzed at 0° C. with 200 ml of 6N hydrochloric acid and 250 ml of water. The organic phase is then washed with water, thereafter with 10% bicarbonate solution and again with water. After drying and evaporation of the solvents, the expected product is obtained by distillation. Boiling point: 60°-65° C. (150 mm/Hg)

References:

Adir et Compagnie US5296498, 1994, A