[CH3:1][Si]([N-][Si](C)(C)C)(C)C.[Na+].[Br-].[CH3:12][C:13]([C:15]1[CH:20]=[CH:19][C:18]([O:21][CH3:22])=[CH:17][C:16]=1[F:23])=O>C1COCC1>[F:23][C:16]1[CH:17]=[C:18]([O:21][CH3:22])[CH:19]=[CH:20][C:15]=1[C:13]([CH3:1])=[CH2:12]A solution of sodium bis(trimethylsilyl)-amide, 11.0M in tetrahydrofuran (714 mL, 0.714 mol) was added to a suspension of methyltriphenylphosphonum bromide (255 g, 0.714 mol) in THF (2.50 L) cooled with an ice bath. The resultant yellow colored suspension was stirred for 30 min at ice bath temperature and then cooled to −78° C. A solution of 2-fluoro-4-methoxyacetophenone (100 g, 0.595 mol) in THF (200 mL) was added dropwise and stirred at −78° C. for 1.5 h. The reaction mixture was allowed to warm to room temperature for one hour, quenched with acetic acid (˜80 mL) where color change was observed from yellow to off white and stirred for 30 min (pH ˜7)(slight exotherm noted). The mixture was concentrated to a slush, diluted with 7:2 hexane:EtOAc, and was allowed to sit overnight. Solids were removed by filtration and the filtrate was concentrated to yellow oil. The title compound was obtained after flash chromatography using 9:1 hexane:EtOAc as the eluant.
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