Reacción #217123

Ecuación de reacción

methoxydiethylborane

(R)-6-cyano-5-hydroxy-3-oxo-N,N-diphenylhexanamide

methanol

sodium borohydride

→

6-cyano-3,5-dihydroxy-N,N-diphenylhexanamide

Disolventes

tetrahydrofuran

ethyl acetate

tetrahydrofuran

Condiciones de reacción

Tratamiento posterior

1. 1
   TemperaturaThe reaction is cooled to -78° C.
2. 2
   TemperaturaThe reaction mixture is maintained at -78° C. for 5 hours
3. 3
   Temperaturato warm to room temperature
4. 4
   OtroThe reaction is quenched by the addition of acetic acid (40 mL)
5. 5
   Concentraciónconcentrated by vacuum distillation to an oil
6. 6
   workup.DISSOLUTIONThe residue is dissolved with methanol (400 mL)
7. 7
   Concentraciónconcentrated by vacuum distillation
8. 8
   workup.DISSOLUTIONredissolved with methanol (300 mL)
9. 9
   workup.DISTILLATIONreconcentrated by vacuum distillation
10. 10
    Otroto give a yellow oil
11. 11
    Lavadowashed with deionized water (500 mL)
12. 12
    ConcentraciónThe ethyl acetate solution is concentrated by vacuum distillation

Procedimiento

Crude (R)-6-cyano-5-hydroxy-3-oxo-N,N-diphenylhexanamide, approximately 0.2 mol, is dissolved in tetrahydrofuran (200 mL) and methanol (100 mL) under a nitrogen atmosphere. The solution is cooled to -20° C., and a 50% solution of methoxydiethylborane in tetrahydrofuran (105 mL) is added. The reaction is cooled to -78° C., and sodium borohydride (24 g, 0.63 mol) is added over 30 minutes. The reaction mixture is maintained at -78° C. for 5 hours, allowed to warm to room temperature, and stand for 10 hours under a nitrogen atmosphere. The reaction is quenched by the addition of acetic acid (40 mL) and concentrated by vacuum distillation to an oil. The residue is dissolved with methanol (400 mL), concentrated by vacuum distillation, redissolved with methanol (300 mL), and reconcentrated by vacuum distillation to give a yellow oil. The oil is taken up in ethyl acetate (300 mL) and washed with deionized water (500 mL). The ethyl acetate solution is concentrated by vacuum distillation to give [R-(R*,R*)])-6-cyano-3,5-dihydroxy-N,N-diphenylhexanamide as an oil which is used without further purification. A small sample is purified by column chromatography on flash silica gel (60:40 hexane:ethyl acetate) as an oil.

Fuente