[F:1][C:2]1[CH:3]=[C:4]([CH:11]([CH3:17])[C:12]([O:14][CH2:15][CH3:16])=[O:13])[C:5]2[O:9][CH:8]=[CH:7][C:6]=2[CH:10]=1.[CH3:18][Si]([N-][Si](C)(C)C)(C)C.[Li+].IC>O1CCCC1.C(OCC)(=O)C>[CH3:17][C:11]([C:4]1[C:5]2[O:9][CH:8]=[CH:7][C:6]=2[CH:10]=[C:2]([F:1])[CH:3]=1)([CH3:18])[C:12]([O:14][CH2:15][CH3:16])=[O:13]A solution of 0.17 gm (0.71 mMol) ethyl 2-(5-fluorobenzofur-7-yl)propionate (EXAMPLE 39) in 2.5 mL tetrahydrofuran was cooled to −78° C. To this solution were added 0.89 mL (0.89 mmol) lithium bis(trimethylsilyl)amide (1.0 M in hexane). After stirring at −78° C. for 1 hour, the reaction mixture was quenched by the addition of 0.13 mL (2.13 mMol) iodomethane. The reaction mixture was allowed to warm to room temperature and was diluted with ethyl acetate. This mixture was then washed sequentially with water, saturated aqueous sodium bicarbonate, and saturated aqueous sodium chloride. The remaining organics were concentrated under reduced pressure. The residue was subjected to silica gel chromatography, eluting with hexane containing 20% ethyl acetate. Fractions containing product were combined and concentrated under reduced pressure to provide 0.16 gm (90%) of the desired compound.
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