[Si:1]([O:8][C:9]1[C:14]([CH2:15][CH2:16][CH3:17])=[CH:13][C:12]([CH:18]=[CH2:19])=[CH:11][C:10]=1[CH2:20][CH2:21][CH3:22])([C:4]([CH3:7])([CH3:6])[CH3:5])([CH3:3])[CH3:2].B.C1C[O:27]CC1.[O-][O-].[Na+].[Na+].[OH-].[Na+]>C1COCC1.C(OCC)(=O)C>[Si:1]([O:8][C:9]1[C:10]([CH2:20][CH2:21][CH3:22])=[CH:11][C:12]([CH2:18][CH2:19][OH:27])=[CH:13][C:14]=1[CH2:15][CH2:16][CH3:17])([C:4]([CH3:7])([CH3:6])[CH3:5])([CH3:3])[CH3:2]To a solution of 475 mg (1.48 mmol) of the product of Step B in 3 mL of THF at 0° C. was added 1.6 mL (1.62 mmol) of a 1N borane/THF solution. After 1 hour TLC indicated that the starting material had been consumed. The reaction mixture was quenched with 3 drops of methanol and then 0.70 mL (6.22 mmol) of 30% sodium peroxide and 6.2 mL (6.2 mmol) of 1N sodium hydroxide were added. After two hours the reaction mixture was diluted with ethyl acetate and washed with water and brine. The organic layer was then dried over sodium sulfate, filtered and concentrated. Flash chromatography (silica gel, hexane/ethyl acetate 4:1) gave 265 mg of the title compound as a clear oil.
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