A solution of butyllithium in hexane (1.6 molar; 30 ml) was added, dropwise, under a nitrogen atmosphere to [2-(4-fluoro-3-phenoxyphenyl)ethyl]triphenylphosphonium bromide (26.76 g; 48 mmol) in absolute tetrahydrofuran (200 ml). After stirring for two hours, 2-(4-methoxyphenyl)-2-trifluoromethylpropionaldehyde (10.13 g; 43.63 mmol) dissolve in absolute tetrahydrofuran (80 ml) was added, dropwise. The mixture was heated at reflux for 3 hours and then added to ice-water, extracted with ethyl acetate, the extract dried over sodium sulphate and evaporated. After chromatography on silica gel using hexane/ethyl acetate as eluent, there was obtained 1-(4-fluoro-3-phenoxyphenyl)-4-(4-phenoxyphenyl)-4-trifluoromethyl-2-pentene (15.2 g=80.5% of theory).
