Reacción #172110

Ecuación de reacción

n-butanal

HCl

n-butanal

NH4Cl

ethyl 2-bromo-2,2-difluoroacetate

→

Ethyl 2,2-difluoro-3-hydroxyhexanoate

Disolventes

THF

Condiciones de reacción

Tratamiento posterior

1. 1
   workup.ADDITIONSM1 (304 g, 1.50 mol) was added dropwise at 35° C. without external heating
2. 2
   workup.ADDITIONAfter the addition
3. 3
   TemperaturaThe reaction mixture was then cooled to about 5° C.
4. 4
   workup.STIRRINGThe mixture was stirred for 15 min.
5. 5
   Filtraciónfiltered through a plug of celite
6. 6
   Lavadothe filter cake was washed once with MTBE (1 L)
7. 7
   OtroThe combined filtrate was then separated
8. 8
   Extracciónthe aqueous layer was extracted once with MTBE (1 L)
9. 9
   LavadoThe combined organic layers were washed once with sat. aq. NaHCO3 (1 L), once with sat. aq. NH4Cl (1 L)
10. 10
    Concentraciónconcentrated at <50° C. under reduced pressure
11. 11
    Otroto give 281 g of crude IM1 with 80% GC purity
12. 12
    workup.DISTILLATIONThe crude IM1 was purified by vacuum distillation
13. 13
    Otroto provide 160 g IM1 with 98% GC purity in 58% GC total yield

Procedimiento

To a mechanically stirred mixture of zinc (108 g, 1.66 mol), n-butanal (100 g, 1.39 mol), CeCl3.7H2O (10.14 g, 0.027 mol) and anhydrous THF (1.3 L) at about 25° C. was added ethyl 2-bromo-2,2-difluoroacetate (SM1, 33.8 g, 0.167 mol) under N2. The mixture was stirred at about 25° C. until the reaction had initiated, then SM1 (304 g, 1.50 mol) was added dropwise at 35° C. without external heating. After the addition completed, the mixture was stirred at 20˜35° C. until n-butanal was less than 2.0%. The reaction mixture was then cooled to about 5° C. and sat. aq. NH4Cl (800 mL) was added slowly at about 5° C., and then adjust pH 3.0 with 6 N HCl. The mixture was stirred for 15 min. and then filtered through a plug of celite; the filter cake was washed once with MTBE (1 L). The combined filtrate was then separated and the aqueous layer was extracted once with MTBE (1 L). The combined organic layers were washed once with sat. aq. NaHCO3 (1 L), once with sat. aq. NH4Cl (1 L) and then concentrated at <50° C. under reduced pressure to give 281 g of crude IM1 with 80% GC purity. The crude IM1 was purified by vacuum distillation to provide 160 g IM1 with 98% GC purity in 58% GC total yield.

Fuente