反应详情

温度

-20 °C

To 3.15 gm (12 mmol) of PPh3 in 100 mL of dry THF at −20° C. was added 1.89 mL (12 mmol) of DEAD dropwise. The solution was allowed to stir 10 min. at −20° C. After 10 min, a solution containing 1.87 gm (10 mmol) of 1-t-butoxycarbonyl-3-(R)-hydroxypyrrolidine in 20 mL of dry THF was added dropwise. The solution was again allowed to stir 10 min at −20° C. After 10 min, to the solution was added 2.08 gm (10 mmol) of 2-chloro-3-bromo-5-hydroxypyridine at once. The solution was allowed to stir at room temperature overnight. Next day, solvent was removed under reduced pressure. The crude product was purified by flash chromatography (3:1, hexane:ethyl acetate) to obtain 3.65 gm (65%) of a foamy residue: 1H NMR (300 MHz, CD3OD) δ8.05 (1H, d, J=2.5 Hz), 7.78 (1H, d, J=2.5 Hz), 5.09 (1H, s), 3.66-3.32 (4H, m), 2.18 (2H, m), 1.46 (9H, s).

1. waitAfter 10 min
2. additionwas added dropwise
3. stirringto stir 10 min at −20° C
4. waitAfter 10 min
5. stirringto stir at room temperature overnight
6. customNext day, solvent was removed under reduced pressure
7. customThe crude product was purified by flash chromatography (3:1, hexane:ethyl acetate)