Reacción #4353

Ecuación de reacción

isopentyl magnesium bromide

HCl

Ts-Leu

n-butyl lithium

→

desired product

Rendimiento 41.0%

(4S)-2,8-Dimethyl-4-[(toluenesulfonyl)amino]-5-nonanone

Rendimiento 41.0%

Disolventes

THF

THF

hexane

Condiciones de reacción

Tratamiento posterior

1. 1
   TemperaturaThe mixture was heated
2. 2
   Temperaturaat reflux for 3 days
3. 3
   Temperaturacooled
4. 4
   workup.ADDITIONpoured into 0° C
5. 5
   OtroThe layers were separated
6. 6
   Extracciónthe aqueous phase was extracted with ether (3×150 ml)
7. 7
   LavadoThe combined organic layers were washed with saturated NaHCO3 (2×150 ml) and brine (150 ml)
8. 8
   OtroDrying
9. 9
   Otroevaporating
10. 10
    Otroprovided a residue which
11. 11
    Otrowas chromatographed on silica gel

Procedimiento

To a stirred -78° C. solution of Ts-Leu (15 g, 53 mmol) in dry THF (240 ml) was added n-butyl lithium (57.8 ml of a 0.91M solution in hexane) followed 15 minutes later by isopentyl magnesium bromide (185 ml of a 0.8M solution in THF). The mixture was heated at reflux for 3 days, then cooled and poured into 0° C. 1M HCl (500 ml). The layers were separated and the aqueous phase was extracted with ether (3×150 ml). The combined organic layers were washed with saturated NaHCO3 (2×150 ml) and brine (150 ml). Drying and evaporating provided a residue which was chromatographed on silica gel to give 7.43 g (41%) of the desired product. Mass spectrum: (M+H)+ =340.

Fuente