Reacción #48300

Ecuación de reacción

1-Iodo-4-(trifluoromethyl)benzene

dicyclohexylphosphino-2′,6′-dimethoxy-1,1′-biphenyl

Iodine

(R)-methyl 2-(tert-butoxycarbonyl)-3-iodopropanoate

→

(S)-methyl 2-(tert-butoxycarbonyl)-3-(4-(trifluoromethyl)phenyl)propanoate

Disolventes

DMF

Condiciones de reacción

Tratamiento posterior

1. 1
   Temperaturathe solid mixture was heated under vacuum for 10 minutes
2. 2
   OtroThe flask was flushed with nitrogen three times
3. 3
   Temperaturato cool
4. 4
   workup.ADDITIONDMF (0.5 mL, degassed with nitrogen) was added
5. 5
   workup.ADDITIONwas added dropwise
6. 6
   workup.WAITto come to RT for 30 minutes
7. 7
   OtroThe flask was purged with nitrogen
8. 8
   Temperaturaheated at 40° C
9. 9
   workup.WAITAfter 3 hours the reaction was allowed
10. 10
    Temperaturato cool
11. 11
    Otropartitioned between EtOAc
12. 12
    ExtracciónThe aqueous layer was extracted with EtOAc
13. 13
    Lavadothe combined organic layers were washed with water, brine
14. 14
    Secadodried over sodium sulfate
15. 15
    ConcentraciónConcentration and purification by silica gel chromatography (6:1 Hexanes/EtOAc)

Procedimiento

Iodine (0.0140 g, 0.0553 mmol) was added to zinc (0.542 g, 8.29 mmol) and the solid mixture was heated under vacuum for 10 minutes. The flask was flushed with nitrogen three times and allowed to cool. DMF (0.5 mL, degassed with nitrogen) was added and the suspension was cooled to 0° C. and stirred while (R)-methyl 2-(tert-butoxycarbonyl)-3-iodopropanoate (1.82 g, 5.53 mmol) in DMF (2.8 mL) was added dropwise. The mixture was stirred for 30 minutes at 0° C. and then allowed to come to RT for 30 minutes. 1-Iodo-4-(trifluoromethyl)benzene (1.50 g, 5.53 mmol), tris(dibenzylideneacetone)dipalladium (0.101 g, 0.111 mmol), and dicyclohexylphosphino-2′,6′-dimethoxy-1,1′-biphenyl (S-Phos) (0.182 g, 0.442 mmol) were added. The flask was purged with nitrogen and heated at 40° C. After 3 hours the reaction was allowed to cool and partitioned between EtOAc and an aqueous solution of ˜9:1 saturated ammonium chloride/ammonium hydroxide. The aqueous layer was extracted with EtOAc and the combined organic layers were washed with water, brine, and dried over sodium sulfate. Concentration and purification by silica gel chromatography (6:1 Hexanes/EtOAc) afforded (S)-methyl 2-(tert-butoxycarbonyl)-3-(4-(trifluoromethyl)phenyl)propanoate.

Fuente