To a suspension of methyltriphenylphosphonium bromide (6.73 g, 18.83 mmol) in anhydrous THF (20 mL) was added dropwise n-butyllithium (11.77 mL, 18.83 mmol) under −78° C. over 30 min. It was stirred for 1 h, then was added by 4-{[4-chloro-3-(trifluoromethyl)phenyl]oxy}-3-fluorobenzaldehyde (5.0 g, 15.69 mmol). It was warmed slowly to room temperature and stirred for overnight at room temperature. Purification via a flash column chromatography then afforded the title compound (4.0 g, 80% yield). LCMS: rt=5.7 min, [M+H+]=316
