Reacción #53813

Ecuación de reacción

trans-(4-Hydroxy-cyclohexyl)-methyl-carbamic acid tert-butyl ester

1,4-Dibromobutane

NaOH

→

trans-[4-(4-Bromo-butoxy)-cyclohexyl]-methyl-carbamic acid tert-butyl ester

Rendimiento 76.0%

Disolventes

CH2Cl2

Condiciones de reacción

Tratamiento posterior

1. 1
   workup.ADDITIONwere added
2. 2
   Otrothe layers were separated
3. 3
   ExtracciónThe inorganic layer was extracted with CH2Cl2
4. 4
   Lavadothe combined organic layers washed with brine
5. 5
   Secadodried over Na2SO4
6. 6
   OtroThe excess of dibromide was removed in vacuo
7. 7
   Otrothe residue was purified by column chromatography on silica gel with hexane:EtOAc 4:1 as eluent

Procedimiento

To a suspension of 2.0 g (8.7 mmol) trans-(4-Hydroxy-cyclohexyl)-methyl-carbamic acid tert-butyl ester in 56.5 ml (261 mmol, 30 eq) 1,4-Dibromobutane, 0.89 g (2.6 mmol, 0.3 eq) tetrabutylammoniumhydrogensulfate and 56 ml 50% aqueous NaOH were added. The mixture was stirred at RT for 4 days, CH2Cl2 was added and the layers were separated. The inorganic layer was extracted with CH2Cl2, the combined organic layers washed with brine and dried over Na2SO4. The excess of dibromide was removed in vacuo and the residue was purified by column chromatography on silica gel with hexane:EtOAc 4:1 as eluent yielding 2.4 g (76%) trans-[4-(4-Bromo-butoxy)-cyclohexyl]-methyl-carbamic acid tert-butyl ester as light yellow oil, MS: 364 (MH+, 1Br).

Fuente