反应详情

Lithium hexamethyldisilazide (250 ml of a 1M solution in THF, 0.25 mol) was cooled in an argon atmosphere to −78° C. and ethyl acetate (23 ml, 0.26 mol) was added dropwise with stirring. Stirring was continued for one hour at −78° C., then methyl 2,2,3,3-tetrafluoropropionate (22 g, 0.137 mol) was added dropwise with stirring. Stirring was continued for three hours at −78° C., then a saturated solution of ammonium chloride (175 ml) was added dropwise. The mixture was allowed to reach room temperature overnight. The mixture was acidified with 1M HCl, the phases were separated. The aqueous phase was extracted with ethyl acetate, the combined organic phases were washed two times with 1M HCl, brine, dried over sodium sulfate. The solvent was removed under reduced pressure and the residue was purified by vacuum distillation to yield 25.7 g (0.119 mmol, 87%) of a colourless liquid that was used directly in the next step.

1. stirringStirring
2. stirringwith stirring
3. stirringStirring
4. waitwas continued for three hours at −78° C.
5. waitto reach room temperature overnight
6. customthe phases were separated
7. extractionThe aqueous phase was extracted with ethyl acetate
8. washthe combined organic phases were washed two times with 1M HCl, brine
9. dry with materialdried over sodium sulfate
10. customThe solvent was removed under reduced pressure
11. distillationthe residue was purified by vacuum distillation