Hydrochloric Acid → 3-[4-Bromo-5,5-dimethyl-5h-furan-(2e)-ylidene]-5-fluoro-1,3-dihydro-indol-2-one

Participants

Reaction Conditions

Reaction Steps

To 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.

Provenance & Evidence