[CH2:1]([CH:5]1[CH2:10][CH2:9][CH2:8][CH:7]([CH2:11][C:12]([O:14][CH2:15][CH3:16])=[O:13])[C:6]1=[O:17])/[CH:2]=[CH:3]/[CH3:4].B.[OH-:19].[Na+].OO>O1CCCC1.[Cl-].[Na+].O>[CH2:3]([CH:2]1[CH2:1][CH:5]2[CH2:10][CH2:9][CH2:8][CH:7]([CH2:11][C:12]([O:14][CH2:15][CH3:16])=[O:13])[C:6]2([OH:19])[O:17]1)[CH3:4]
To a stirred solution of ethyl {3-[(2E)-but-2-en-1-yl]-2-oxocyclohexyl}acetate (565 mg, 2.37 mmol) in tetrahydrofuran (20 ml) at 0° C. was added borane.tetrahydrofuran complex (1 M in tetrahydrofuran, 3.56 ml, 3.56 mmol) and the reaction allowed to stir at 0° C. for 35 min. Sodium hydroxide (4N, 5.6 ml) and hydrogen peroxide (5.6 ml) were added and the reaction allowed to stir at room temperature for 1 h. Diluted with brine, then extracted three times with dichloromethane. The combined organics were washed twice with brine, dried over sodium sulfate, concentrated in vacuo and purified by column chromatography (50% EtOAc/hexanes). The desired title compound (345 mg) was obtained as a colourless oil as a complex mixture of diastereomers.
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