Reaktion #936203

Reaktionsgleichung

hydrochloric acid

Benzylmagnesium chloride

Diethylchlorophosphite

diethyl ether

water

→

benzylphosphinic acid

Ausbeute 32.0%

methyl O-benzylphosphinic acid

Ausbeute 32.0%

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturwhile maintaining a temperature below 10° C
2. 2
   SonstigeA thick white slurry formed
3. 3
   FiltrationThe mixture was filtered under a nitrogen atmosphere
4. 4
   Sonstigethe filtrate evaporated under reduced pressure
5. 5
   Sonstigeto give a clear and colorless liquid
6. 6
   workup.ADDITIONwas added
7. 7
   SonstigeAn exothermic reaction
8. 8
   workup.STIRRINGstirring
9. 9
   workup.WAITwas continued for an additional 30 minutes
10. 10
    Extraktionfollowed by extraction with ethyl acetate
11. 11
    Waschenwashed with brine
12. 12
    Trocknendried (MgSO4)
13. 13
    Sonstigeevaporated
14. 14
    workup.ADDITIONThe clear light golden liquid was added to sodium hydroxide (50 mL, 2.0 M NaOH)
15. 15
    workup.STIRRINGstirred for one hour
16. 16
    Waschenwashed with diethyl ether
17. 17
    Extraktionextracted with ethyl acetate
18. 18
    Trocknendried (MgSO4)
19. 19
    Sonstigeevaporated

Vorschrift

Diethylchlorophosphite (25 g, 0.16 mol) in 100 mL of dry diethyl ether was cooled to 0° C. under an atmosphere of nitrogen. Benzylmagnesium chloride (80 mL, 0.16 mol, 2.0 M solution in Et2O) was added dropwise over two hours while maintaining a temperature below 10° C. A thick white slurry formed and stirring was continued at room temperature for 1 hour. The mixture was filtered under a nitrogen atmosphere and the filtrate evaporated under reduced pressure to give a clear and colorless liquid. The liquid was stirred as 15 mL of water was added followed by 0.5 ml concentrated hydrochloric acid. An exothermic reaction was observed and stirring was continued for an additional 30 minutes followed by extraction with ethyl acetate. The organics were combined, washed with brine, dried (MgSO4) and evaporated. The clear light golden liquid was added to sodium hydroxide (50 mL, 2.0 M NaOH), stirred for one hour and washed with diethyl ether. The aqueous layer was acidified to pH 1.0 with concentrated hydrochloric acid and extracted with ethyl acetate. The organics were combined, dried (MgSO4) and evaporated to give benzylphosphinic acid (1, R=CH2Ph, R1+H) (8 g, 32%) as a clear light golden oil.

Quelle