Reaktion #155529

Reaktionsgleichung

NaHCO3

Boron trifluoride etherate

5,5,5-trifluoropentanoic acid

tert-butyl 2,2,2-trichloroacetimidate

→

tert-butyl 5,5,5-trifluoropentanoate

Ausbeute 98.1%

Lösungsmittel

THF

hexane

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturto warm to room temperature overnight
2. 2
   workup.STIRRINGstirred for 30 min
3. 3
   FiltrationThe mixture was filtered through MgSO4
4. 4
   Waschenwashed with hexanes (200 mL)
5. 5
   workup.WAITto rest for 45 min
6. 6
   Sonstigethe resulting solid material was removed
7. 7
   Filtrationby filtering on the same MgSO4
8. 8
   Filtrationfilter again
9. 9
   Waschenwashed with hexanes (100 mL)
10. 10
    Einengenconcentrated under reduced pressure
11. 11
    Temperaturwithout heat
12. 12
    Filtrationfiltered through a clean fritted funnel
13. 13
    Waschenwashed with hexane (5 mL)
14. 14
    Einengenconcentrated under reduced pressure
15. 15
    Temperaturwithout heat
16. 16
    FiltrationThe resulting neat oil was filtered through a 0.45 μm nylon membrane
17. 17
    Filtrationfilter disk

Vorschrift

To a stirred solution of 5,5,5-trifluoropentanoic acid (5 g, 32.0 mmol) in THF (30 mL) and hexane (30 mL) at 0° C., was added tert-butyl 2,2,2-trichloroacetimidate (11.46 mL, 64.1 mmol). The mixture was stirred for 15 min at 0° C. Boron trifluoride etherate (0.406 mL, 3.20 mmol) was added and the reaction mixture was allowed to warm to room temperature overnight. To the clear reaction mixture was added solid NaHCO3 (5 g) and stirred for 30 min. The mixture was filtered through MgSO4 and washed with hexanes (200 mL). The solution was allowed to rest for 45 min, and the resulting solid material was removed by filtering on the same MgSO4 filter again, washed with hexanes (100 mL) and concentrated under reduced pressure without heat. The volume was reduced to about 30 mL, filtered through a clean fritted funnel, washed with hexane (5 mL), and then concentrated under reduced pressure without heat. The resulting neat oil was filtered through a 0.45 μm nylon membrane filter disk to provide tert-butyl 5,5,5-trifluoropentanoate (6.6 g, 31.4 mmol 98% yield) as a colorless oil: 1H NMR (400 MHz, CDCl3) δ ppm 1.38 (s, 9H) 1.74-1.83 (m, 2H) 2.00-2.13 (m, 2H) 2.24 (t, J=7.28 Hz, 2H).

Quelle