[CH2:1]([Li])[CH2:2][CH2:3][CH3:4].[C:6]1(=[O:12])[CH2:11][CH2:10][CH2:9][CH:8]=[CH:7]1>CSC.CCCCCC.[Cu](I)I>[CH2:1]([CH:8]1[CH2:9][CH2:10][CH2:11][C:6](=[O:12])[CH2:7]1)[CH2:2][CH2:3][CH3:4]A solution of copper iodide (6.3 mmol) in dimethyl sulphide (12 ml) is cooled to 50° C. A solution of butyl lithium (6.2 mmol) is added dropwise accompanied by stirring and stirred for a further 5 to 15 mins. The reaction mixture is cooled to −78° C. and then a solution precooled to −78° C. of cyclohex-2-enone (6 mmol), dissolved in dimethyl sulphide (1 ml), is slowly added dropwise. After stirring for one hour at −78° C. the mixture is quenched with saturated aqueous ammonium chloride solution. The reaction mixture which has been heated to room temperature is extracted with diethyl ether. The combined ether phases are washed with saturated aqueous ammonium chloride solution and dried over sodium sulphate. After evaporating-off of the solvent the residue obtained is taken up in hexane, the solution is filtered and concentrated by evaporation. After chromatography of the residue on silica gel with ethyl acetate/hexane 1:4 pure 3-butylcyclohexanone is obtained (Tetrahedron 1989, 45 (2), 425-434).
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