C([O:8][CH2:9][C@H:10]1[O:14][C:13](=[O:15])[CH2:12][C@@H:11]1[CH:16]1[O:20][CH2:19][CH2:18][O:17]1)C1C=CC=CC=1>CO.[Pd]>[O:17]1[CH2:18][CH2:19][O:20][CH:16]1[C@@H:11]1[C@@H:10]([CH2:9][OH:8])[O:14][C:13](=[O:15])[CH2:12]1To a solution of dihydrofuranone (14) (0.5 g, 1.79 mmol) in MeOH (30 mL) was added Pd/C (25 mg). The mixture was stirred at room temperature under an H2 balloon for 24 hours, and then filtered over Celite. Removal of solvent under reduced pressure, followed by column chromatography on silica gel (35% EtOAc in hexanes as the eluent) yielded the compound (15) (301 mg, 89%) as a white solid, Rf=0.28 (50% EtOAc in hexanes), [α]25D 22° (c 1.32, CHCl3); 1H-NMR (500 MHz, CDCl3) δ: 2.54 (dd, 1H, J=6.0, 11.4 Hz), 2.68-2.81 (m, 2H), 3.66 (dd, 1H, J=3.9-8.5 Hz), 3.88-3.95 (m, 3H), 3.97-4.02 (m, 2H), 4.53 (m, 1H), 4.91 (d, 1H, J=3.9 Hz); 13C-NMR (125.8 MHz, CDCl3) δ: 30.68, 40.12, 64.36, 65.77, 81.07, 103.94, 176.83.
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