[F:1][C:2]1[CH:3]=[C:4]2[C:8](=[CH:9][CH:10]=1)[NH:7][C:6](=[O:11])[CH2:5]2.[Li+].C[Si]([N-][Si](C)(C)C)(C)C.[Br:22][C:23]1[C:27]([CH3:29])([CH3:28])[O:26][C:25](=O)[CH:24]=1.Cl>C1COCC1.O>[Br:22][C:23]1[C:27]([CH3:29])([CH3:28])[O:26]/[C:25](=[C:5]2/[C:6](=[O:11])[NH:7][C:8]3[C:4]/2=[CH:3][C:2]([F:1])=[CH:10][CH:9]=3)/[CH:24]=1To a solution of 5-fluorooxindole (7.5 g, 49 mmol) in THF (80 mL) at 0° C., was added 1 M LHMDS in THF (100 mL, 100 mmol). The reaction mixture was stirred at 0° C. for 20 minutes. A solution of 4-bromo-5,5-dimethyl-5H-furan-2-one (6.4 g, 33 mmol) in THF (20 mL) was added to the reaction mixture. The reaction was stirred at 0° C. for 30 minutes and then allowed to warm to room temperature over 5 hours. To the reaction mixture was added aqueous 2 M HCl (100 mL). The resulting mixture was stirred at 60-65° C. for 1 hour, cooled to room temperature, poured into water (3000 mL) and stirred at room temperature for 2 hours. The precipitates separated and were collected, washed with water, and dried in vacuo to provide 3-[4-bromo-5,5-dimethyl-5H-furan-(2E)-ylidene]-5-fluoro-1,3-dihydro-indol-2-one as a yellow solid (8.7 g, yield 80%), which was used for the next reaction without further purification.
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