Reacción #11343

Ecuación de reacción

N-benzyloxycarbonyl-L-phenylalanine chloromethyl ketone

sodium borohydride

→

N-benzyloxycarbonyl-3(S)-amino-1-chloro-4-phenyl-2(S)-butanol

Rendimiento 48.4%

Disolventes

methanol

tetrahydrofuran

—

hexanes

Condiciones de reacción

Tratamiento posterior

1. 1
   Concentraciónconcentrated in vacuo
2. 2
   workup.DISSOLUTIONThe residue was dissolved in 1000 mL of ethyl acetate
3. 3
   Lavadowashed with 1N KHSO4, saturated aqueous NaHCO3, saturated aqueous NaCl
4. 4
   Secadodried over anhydrous MgSO4
5. 5
   Filtraciónfiltered
6. 6
   Concentraciónconcentrated in vacuo
7. 7
   Otroto give an oil
8. 8
   Temperaturato cool to room temperature where upon crystals
9. 9
   Otroformed
10. 10
    Otrothat were isolated by filtration
11. 11
    Lavadowashed with copious amounts of hexanes
12. 12
    OtroThis solid was then recrystallized from hot ethyl acetate and hexanes

Procedimiento

To a solution of N-benzyloxycarbonyl-L-phenylalanine chloromethyl ketone (75 g, 0.2 mol) in a mixture of 800 mL of methanol and 800 mL of tetrahydrofuran was added sodium borohydride (13.17 g, 0.348 mol, 1.54 equiv.) over 100 min. The solution was stirred at room temperature for 2 hours and then concentrated in vacuo. The residue was dissolved in 1000 mL of ethyl acetate and washed with 1N KHSO4, saturated aqueous NaHCO3, saturated aqueous NaCl, dried over anhydrous MgSO4, filtered and concentrated in vacuo to give an oil. The crude product was dissolved in 1000 mL of hexanes at 60° C. and allowed to cool to room temperature where upon crystals formed that were isolated by filtration and washed with copious amounts of hexanes. This solid was then recrystallized from hot ethyl acetate and hexanes to provide 32.3 g 43% of N-benzyloxycarbonyl-3(S)-amino-1-chloro-4-phenyl-2(S)-butanol, mp 150–151° C., FAB MS: MLi+=340.

Fuente