[O:1]1[CH2:6][CH2:5][CH2:4][CH2:3][CH:2]1[O:7][C@@H:8]1[CH2:12][C@H:11]([OH:13])[CH:10]=[CH:9]1.[C:14](OC(=O)C)(=[O:16])[CH3:15].CN(C1C=CC=CN=1)C.C(OCC)(=O)C>N1C=CC=CC=1>[O:1]1[CH2:6][CH2:5][CH2:4][CH2:3][CH:2]1[O:7][C@@H:8]1[CH2:12][C@H:11]([O:13][C:14](=[O:16])[CH3:15])[CH:10]=[CH:9]1
Dissolve (-)-cis-4-(tetrahydro-pyran-2-yloxy)-cyclopent-2-enol (292 mg, 1.59 mmol, prepared in example 11) in pyridine (2.8 mL) and treat with acetic anhydride (0.39 mL) and dimethylaminopyridine (16 mg). Stir the reaction overnight. Concentrate the reaction under vacuum, dissolve the residue with ethyl acetate (10 mL). Wash with 0.5M hydrochloric acid that is 1/2 saturated with brine (2×10 mL), saturated sodium bicarbonate (10 mL), brine (10 mL), dry over anhydrous magnesium sulfate, filter and concentrate under vacuum. Purify the residue by chromatography (silica gel, 10 g, 1.5×4 cm columnar 20% ethyl acetate/hexane) to provide the title compound (290 mg, 81%).
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