反应详情

Cool a solution of 5-[1,3]dioxolan-2-yl-2-fluoro-pyridine (2.0 g, 11.8 mmol) in THF (20 mL) to −75° C. Add lithium diisopropylamide (2 M in THF, 6 mL, 12 mmol) over a period of 30 min. Stir the mixture for an additional 3 hours. Add iodine (3.0 g, 11.8 mmol, dissolved in 100 mL of THF). Stir for 2 hours after the addition is complete. Add water (100 mL) to the mixture and allow the temperature to rise to room temperature over 1 hour while stirring. Treat the mixture with saturated aqueous sodium thiosulfate solution (50 mL). Extract the solution with ether. Concentrate the solution in vacuo to a brown oil. Purify by column chromatography (hexane to 20% ethyl acetate in hexane) to afford the title compound (2.1 g, 60%) as a yellow oil. MS (ES) m/z 296 [M+1]+.

1. stirringStir for 2 hours
2. additionafter the addition
3. waitto rise to room temperature over 1 hour
4. stirringwhile stirring
5. extractionExtract the solution with ether
6. concentrationConcentrate the solution in vacuo to a brown oil
7. customPurify by column chromatography (hexane to 20% ethyl acetate in hexane)