[Si:1]([O:8][CH:9]1[CH2:13][CH:12]([O:14]C(=O)C)[CH:11]=[CH:10]1)([C:4]([CH3:7])([CH3:6])[CH3:5])([CH3:3])[CH3:2].O.[OH-].[Li+].O>C1COCC1.CO.O>[Si:1]([O:8][C@@H:9]1[CH2:13][C@H:12]([OH:14])[CH:11]=[CH:10]1)([C:4]([CH3:7])([CH3:6])[CH3:5])([CH3:3])[CH3:2]Dissolve (-)-acetic acid 4-tert-butyldimethylsilyloxy-cyclopent-2-enyl ester (2.3 mmol, prepared in example 10) in THF/methanol/water (2.7/0.9/0.9 mL). Add lithium hydroxide monohydrate (2.5 mmol) with stirring. After stirring for about 3 hours at room temperature, dilute the reaction with water (10 mL) and extract with tert-butyl methyl ether. Combine the organic phases, dry over anhydrous magnesium sulfate, filter and concentrate under vacuum. Purify the residue by flash chromatography (silica gel, 20% ethyl acetate/hexane) to provide the title compound (452 mg, 92% yield) [α]20D =+21.8°, (c=1.02, chloroform).
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