Reacción #1339

Ecuación de reacción

Sodium t-butoxide

1-bromo-1-chloro-2,2,2-trifluoroethane

3-methylbut-1-en-1-al

tetrahydrofuran

→

5-bromo-5-chloro-4-hydroxy-2-methyl-6,6,6-trifluorohex-2-ene

Disolventes

dimethyl formamide

Condiciones de reacción

Tratamiento posterior

1. 1
   Temperaturaby external cooling under a nitrogen atmosphere
2. 2
   Temperaturaexternal cooling
3. 3
   Otrowas removed
4. 4
   Otrothe reaction quenched by the dropwise addition of saturated aqueous ammonium chloride solution
5. 5
   OtroThe mixture was then partitioned between water and diisopropyl ether
6. 6
   Otrothe aqueous phase separated
7. 7
   Lavadowashed with diisopropyl ether (3×25 ml)
8. 8
   LavadoThe organic phase was washed with brine
9. 9
   Secadodried over anhydrous sodium sulphate
10. 10
    Concentraciónconcentrated by evaporation under reduced pressure
11. 11
    OtroAfter purification by a procedure similar to

Procedimiento

Sodium t-butoxide (1.39 g of a 42% solution in dry dimethyl formamide was added dropwise over a period of 5 minutes to a stirred mixture of 1-bromo-1-chloro-2,2,2-trifluoroethane (0.535 ml), 3-methylbut-1-en-1-al (0.538 ml) and dry tetrahydrofuran (10 ml) maintained at a temperature of -78° C. by external cooling under a nitrogen atmosphere. The mixture was then stirred for a further 40 minutes at the temperature after which the external cooling was removed and the reaction quenched by the dropwise addition of saturated aqueous ammonium chloride solution. The mixture was then partitioned between water and diisopropyl ether and the aqueous phase separated, washed with diisopropyl ether (3×25 ml), and the washings combined with the organic phase. The organic phase was washed with brine and dried over anhydrous sodium sulphate and concentrated by evaporation under reduced pressure. After purification by a procedure similar to that set out in the previous Example there was obtained 5-bromo-5-chloro-4-hydroxy-2-methyl-6,6,6-trifluorohex-2-ene (1.39 g), identified by nuclear magnetic resonance and infra-red spectroscopy.

Fuente