反应详情

To a mixture of 3.5 g of ethyl 5-fluoronicotinate (21 mmol) in 80 mL of dry toluene at −78° C. under nitrogen was added 42 mL of 1.0M DIBAL in toluene dropwise with stirring. The mixture was stirred at −78° C. for 3 h and the excess DIBAL was quenched by adding 0.5 mL of EtOAc. The mixture was allowed to warm to room temperature and 100 mML of water was added. The mixture was filtered through celite and the filter cake washed with 3×10 mL of toluene. The layers were separated and the organic phase was washed with brine, dried (MgSO4) and loaded onto a column (silica gel). The product was purified by eluting with 20%-35% EtOAc in hexanes to give 700 mg of 5-fluoro-3-pyridinecarboxaldehyde and 2.0 g of un-reacted starting material.

1. stirringThe mixture was stirred at −78° C. for 3 h
2. customthe excess DIBAL was quenched
3. additionby adding 0.5 mL of EtOAc
4. addition100 mML of water was added
5. filtrationThe mixture was filtered through celite
6. washthe filter cake washed with 3×10 mL of toluene
7. customThe layers were separated
8. washthe organic phase was washed with brine
9. dry with materialdried (MgSO4)
10. customThe product was purified
11. washby eluting with 20%-35% EtOAc in hexanes