反应详情

To a stirring solution of 9.2 mL of LDA (lithium diisopropylamide) (2.0M solution in THF/heptane/ethylbenzene) in 20 mL of THF at −78° C. was added 2-fluoro-5-isopropylpyridine in 40 mL of THF dropwise over a period of 20 min. After 30 min. 4.39 g (17.3 mmol) of iodine in 25 mL of THF was added. After 2 h at −78° C. with the light off, 20 mL of water was added, and the cold bath was removed. Water (80 mL) was added and 9 g of sodium thiosulfate was added in 3 portions. Diethyl ether was added, and the layers were separated. The organic layer was washed with brine, dried over Na2SO4, filtered, and concentrated. Purification by flash silica gel chromatography (5% Et2O/hexanes) provided 1.83 g of 2-fluoro-3-iodo-5-isopropylpyridine with some impurity.

1. customthe cold bath was removed
2. additionWater (80 mL) was added
3. addition9 g of sodium thiosulfate was added in 3 portions
4. additionDiethyl ether was added
5. customthe layers were separated
6. washThe organic layer was washed with brine
7. dry with materialdried over Na2SO4
8. filtrationfiltered
9. concentrationconcentrated
10. customPurification by flash silica gel chromatography (5% Et2O/hexanes)