反应详情

To a freshly prepared solution of LDA (6.25 mmol) in THF (5 ml) was added dropwise a solution of 2-bromo-5-fluoro-4-triethylsilanylpyridine (1.6 g, 5.51 mmol) in THF (12 ml) at −78° C. Stirring was continued at −78° C. for 3 hours. Ethyl 2,2-difluoroacetate (0.58 ml, 5.51 mmol) was added dropwise and the solution was stirred at −78° C. for 3 hours. The reaction mixture was quenched with sat. ammonium chloride solution (20 ml) and ethyl acetate was added. The organic phase was washed with brine, dried over sodium sulfate, filtered and evaporated. The crude brown oil (2.11 g) was chromatographed over silica gel (cyclohexane/ethyl acetate) to give the title compound. 1.53 g (75% yield, mixture of ketone and hydrate form).

1. stirringthe solution was stirred at −78° C. for 3 hours
2. customThe reaction mixture was quenched with sat. ammonium chloride solution (20 ml) and ethyl acetate
3. additionwas added
4. washThe organic phase was washed with brine
5. dry with materialdried over sodium sulfate
6. filtrationfiltered
7. customevaporated
8. customThe crude brown oil (2.11 g) was chromatographed over silica gel (cyclohexane/ethyl acetate)