C(NC(C)C)(C)C.[Li]CCCC.[F:13][C:14]1[CH:15]=[CH:16][CH:17]=[C:18]2[C:22]=1[N:21]([CH3:23])[C:20](=[O:24])[C:19]2([CH3:26])[CH3:25].[CH3:27][Si:28](Cl)([CH3:30])[CH3:29]>O1CCCC1>[F:13][C:14]1[C:15]([Si:28]([CH3:30])([CH3:29])[CH3:27])=[CH:16][CH:17]=[C:18]2[C:22]=1[N:21]([CH3:23])[C:20](=[O:24])[C:19]2([CH3:26])[CH3:25]A solution of diisopropylamine (5.4 g, 7.6 ml, 52.8 mmol) in dry tetrahydrofuran (23 ml) under an argon atmosphere was cooled to −40° C. and a solution of n-BuLi (1.6 M in hexane, 31.6 ml, 50.5 mmol) was added dropwise. The mixture was stirred at −40° C. for 30 minutes and then added to a solution of 7-fluoro-1,3,3-trimethylindolin-2-one (8.875 g, 45.9 mmol) and trimethylsilyl chloride (5.49 g, 6.46 ml, 50.5 mmol) in dry tetrahydrofuran (69 ml) at −75° C. The reaction mixture was warmed to room temperature within 16 hours. The reaction mixture was carefully quenched with water (2 ml) and diluted with ethyl acetate and water. The aqueous phase was extracted ethyl acetate, the combined organic phases were washed with brine and dried over sodium sulfate. The solvent was evaporated and the residue purified by silica gel chromatography using ethyl acetate/heptane as eluent. The title compound was obtained as light yellow oil (8.55 g).
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