[F:1][C:2]([F:12])([F:11])[C:3]1[CH:10]=[CH:9][C:6]([CH:7]=O)=[CH:5][CH:4]=1.C1(P(C2C=CC=CC=2)(C2C=CC=CC=2)=[CH:20][C:21](=[O:23])[CH3:22])C=CC=CC=1>C(Cl)Cl.C1(P(C2C=CC=CC=2)(C2C=CC=CC=2)=CC(=O)C)C=CC=CC=1>[F:1][C:2]([F:12])([F:11])[C:3]1[CH:10]=[CH:9][C:6](/[CH:7]=[CH:20]/[C:21](=[O:23])[CH3:22])=[CH:5][CH:4]=14-(Trifluoromethyl)benzaldehyde (25.0 g, 144 mmol) was taken up in 500 mL of DCM. 1-Triphenylphosphoranylidene-2-propanone (48.0 g, 151 mmol) was added. After 5 hours, an additional 3 g of 1-triphenylphosphoranylidene-2-propanone was added. The mixture was stirred for 10 hours. The solvent was removed under reduced pressure, and the residue was triturated with 500 mL of 5% EtOAc/hexanes. The mixture was filtered, removing a large amount of P(O)Ph3. The residue was taken up in 300 mL of 2.5% EtOAc/hexanes and filtered through a pad of silica. The mixture was concentrated under reduced pressure and the residue was found to be (E)-4-(4-(trifluoromethyl)phenyl)but-3-en-2-one (28.3 g, 92.0% yield). 1H NMR (400 MHz, CDCl3) δ ppm 7.68-7.60 (m, 4H), 7.52 (d, J=16.43 Hz, 1H), 6.78 (d, J=16.4 Hz, 1H), 2.41 (s, 3H).
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