Reacción #2128650

Ecuación de reacción

3,3-dimethyl-bromobutane

4-cyanobenzaldehyde

iodine

3,3-dimethyl-bromobutane

3,3-dimethyl-bromobutane

→

desired intermediate

Rendimiento 62.5%

4-(4,4-Dimethyl-pentanoyl)-benzonitrile

Rendimiento 62.5%

Disolventes

THF

THF

Condiciones de reacción

Tratamiento posterior

1. 1
   Otrofor 2 h
2. 2
   OtroPurge the flask with nitrogen/vacuo several times
3. 3
   workup.ADDITIONAdd
4. 4
   Temperaturareflux the mixture overnight
5. 5
   Temperaturareflux for 30 min
6. 6
   TemperaturaWarm the flask gradually to room temperature overnight
7. 7
   OtroQuench the mixture with 0.1M aqueous HCl (100 mL)
8. 8
   Extracciónextract twice with EtOAc
9. 9
   SecadoDry the combined organic extracts over Na2SO4
10. 10
    Filtraciónfilter
11. 11
    Concentraciónconcentrate in vacuo
12. 12
    OtroPurify the crude mixture by chromatography on silica gel eluting with hexane/EtOAc (19:1)

Procedimiento

Keep Mg turnings (402 mg, 15.251 mmol) in vacuo in a two-neck round bottom flask for 2 h. Purge the flask with nitrogen/vacuo several times. Add a couple crystals of iodine, anhydrous THF (60 mL) and 3,3-dimethyl-bromobutane (0.8 mL, 5.59 mmol) slowly (exothermic reaction observed). Add dropwise the remaining 3,3-dimethyl-bromobutane (1.6 mL, 11.18 mmol) and reflux the mixture overnight. Add some additional 3,3-dimethyl-bromobutane (0.24 mL, 1.67 mmol) and reflux for 30 min. Cool the mixture to −10° C. and add a solution of 4-cyanobenzaldehyde (4 g, 30.502 mmol) in anhydrous THF (40 mL). Warm the flask gradually to room temperature overnight. Quench the mixture with 0.1M aqueous HCl (100 mL) and extract twice with EtOAc. Dry the combined organic extracts over Na2SO4, filter and concentrate in vacuo. Purify the crude mixture by chromatography on silica gel eluting with hexane/EtOAc (19:1) to give the desired intermediate as an oil (0.752 g, 23%).

Fuente