Water → 1,1,1-Trifluoro-2-phenyl-5-methyl-hexa-2,4-diene

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Reaction Steps

65 ml of 15% strength solution of n-butyl-lithium in hexane were added dropwise to a suspension of 41.1 g (0.1 mol) of dry 3,3-dimethylallyl-triphenyl-phosphonium bromide in 300 ml of anhydrous tetrahydrofuran at 0° C. under nitrogen, while stirring. The deep red solution thus obtained was stirred at 0° C. for a further 15 minutes and 17.4 g (0.1 mol) of ≃,≃,≃-trifluoroacetophenone were then added dropwise at 0°-10° C. The mixture was subsequently stirred at room temperature until it was decolorized (about 12 hours). 600 ml of water were then added and the reaction mixture was extracted 5 times with 200 ml of petroleum ether each time. The petroleum ether phases were dried over magnesium sulphate and the solvent was then stripped off in a rotary evaporator under a waterpump vacuum. 150 ml of n-hexane were added to the residue and residual triphenyl-phosphine oxide was filtered off. The solvent was subsequently distilled off from the filtrate under normal pressure and the oily residue was then distilled in vacuo. 12.8 g (56.6% of theory) of 1,1,1-trifluoro-2-phenyl-5-methyl-hexa-2,4-diene were obtained as a slightly reddish liquid with a boiling point of 80°-85° C. under 3 mbar.

Provenance & Evidence