CC1(C)CCCC(C)(C)N1.C([Li])CCC.[C:16]([Si:20]([O:23][CH2:24][CH2:25][C:26]1[CH:31]=[CH:30][CH:29]=[CH:28][C:27]=1[F:32])([CH3:22])[CH3:21])([CH3:19])([CH3:18])[CH3:17].CN([CH:36]=[O:37])C>C1COCC1>[Si:20]([O:23][CH2:24][CH2:25][C:26]1[C:27]([F:32])=[C:28]([CH:29]=[CH:30][CH:31]=1)[CH:36]=[O:37])([C:16]([CH3:19])([CH3:17])[CH3:18])([CH3:21])[CH3:22]A solution of 2,2,6,6-tetramethylpiperidine (11.0 g) in anhydrous THF (200 mL) was cooled to −78° and treated with butyllithium (37.5 mL), added steadily over 5 minutes via a syringe. The solution was stirred at −78° for 15 minutes and then treated with a solution of tert-butyl(2-fluorophenethoxy)dimethylsilane [Aromatic Intermediate 5, step a] (9.9 g) in THF (25 mL), added dropwise over 15 minutes. The solution that was stirred at −78° for 2 hours, then treated with a solution of DMF (9.0 mL) in THF (25 mL), added dropwise over 10 minutes. The solution was stirred at −78° for 1 hour, then the cooling bath was removed and the solution was allowed to warm to room temperature overnight. The reaction mixture was poured into aqueous HCl (0.5M) and extracted three times with ethyl acetate. The combined organic phases were washed three times with water, once with brine, then dried over magnesium sulphate, filtered and concentrated under reduced pressure to afford the titled compound. Yield 10.1 g.
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