Reaction #2446062

Reaction equation

ammonium chloride

tributylphosphine

n-butyllithium

2-cyclopentene-1-one

→

3-butyl-cyclopentanone

Solvents

Diethyl ether

hexane

diethyl ether

Conditions

Workup

1. 1
   Temperatureit was warmed to −40° C.
2. 2
   workup.STIRRINGstirred for another 2.5 hours
3. 3
   Temperaturethe mixture was warmed to room temperature
4. 4
   OtherThe mixture was separated
5. 5
   Extractionthe water layer was extracted with diethyl ether three times
6. 6
   Washthe combined organic layer was washed with brine
7. 7
   DryingThe solution was dried over anhydrous magnesium sulfate
8. 8
   workup.DISTILLATIONthe solvent was distilled off under reduced pressure
9. 9
   OtherThe residue was purified by silica gel chromatography (eluent: ethyl acetate/n-heptane= 1/20 by volume)

Procedure

Diethyl ether (800 ml) and tributylphosphine (83 ml) were added to copper iodide (41.4 g) in a reaction vessel under an atmosphere of nitrogen, and the mixture was cooled to −78° C., and then n-butyllithium (1.65 M, a hexane solution) (19 ml) was added dropwise at a temperature of −70° C. or lower. The stirring was continued at −78° C. for 20 minutes, and 2-cyclopentene-1-one (17.0 g) in a diethyl ether (150 ml) solution was added dropwise at a temperature of −70° C. or lower. After the mixture had been stirred at −78° C. for another 20 minutes, it was warmed to −40° C., and stirred for another 2.5 hours. Then, a saturated aqueous solution of ammonium chloride (600 ml) was added at −40° C., and the mixture was warmed to room temperature. The mixture was separated, and the water layer was extracted with diethyl ether three times, and then the combined organic layer was washed with brine. The solution was dried over anhydrous magnesium sulfate and the solvent was distilled off under reduced pressure. The residue was purified by silica gel chromatography (eluent: ethyl acetate/n-heptane= 1/20 by volume) to give 3-butyl-cyclopentanone (15.4 g).

Source