CC(C)=O.OS(O)(=O)=O.O=[Cr](=O)=O.[Br:14][CH2:15][CH2:16][CH2:17][CH:18]([OH:23])[C:19]([O:21][CH3:22])=[O:20].C(O)(C)C>CC(C)=O.O>[Br:14][CH2:15][CH2:16][CH2:17][C:18](=[O:23])[C:19]([O:21][CH3:22])=[O:20]Jones' reagent (CrO3 : 9.58 g, H2SO4 : 8.47 ml, H2O: 36.8 ml) was added to a magnetically stirred solution of Part (3) compound (12.53 g, 59.3 mmole) in acetone (150 ml) at room temperature. The addition was controlled to maintain the temperature below 35° C. After the completion of the addition, the reaction was stirred at room temperature for 45 minutes. Isopropyl alcohol (30 ml) was added dropwise and stirred for 30 minutes. The reaction was then diluted with H2O (500 ml) and the products were extracted with CH2Cl2 (1 l.). The CH2Cl2 layer was washed with brine (100 ml×3) and dried over MgSO4. Filtration and evaporation of solvents gave the title compound (11.4 g, 54.5 mmole, 92%) as a colorless liquid.
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