Cl[Si:2]([CH:15]([CH3:17])[CH3:16])([CH:12]([CH3:14])[CH3:13])[O:3][Si:4](Cl)([CH:8]([CH3:10])[CH3:9])[CH:5]([CH3:7])[CH3:6].[CH2:18]([O:25][C@H:26]1[C:30](=[CH2:31])[C@H:29]([CH2:32][OH:33])[C@H:28]([OH:34])[C@@H:27]1[OH:35])[C:19]1[CH:24]=[CH:23][CH:22]=[CH:21][CH:20]=1>N1C=CC=CC=1>[CH2:18]([O:25][C@@H:26]1[C@@H:27]([OH:35])[C@@H:28]2[O:34][Si:2]([CH:15]([CH3:17])[CH3:16])([CH:12]([CH3:14])[CH3:13])[O:3][Si:4]([CH:8]([CH3:10])[CH3:9])([CH:5]([CH3:7])[CH3:6])[O:33][CH2:32][C@H:29]2[C:30]1=[CH2:31])[C:19]1[CH:20]=[CH:21][CH:22]=[CH:23][CH:24]=11,3-Dichloro-1,1,3,3-tetraisopropyldisiloxane (5.5 mL, 16.8 mmol) was added dropwise to a solution of triol 5 (4.0 g, 16.0 mmol) in anhydrous pyridine at −30° C. The reaction mixture was allowed to warm up to room temperature gradually and kept at the same temperature for 2 h. After removing the pyridine in vacuo, the residue was dissolved in EtOAc and washed with H2O and brine, dried over magnesium sulfate, filtered and concentrated in vacuo. The residue was purified by column chromatography on a silica gel (EtOAc:Hexanes=1:30 to 1:5) to yield the alcohol 6 (6.5 g, 82%) as a syrup. [α]24D −105.94° (c 0.58, CHCl3); 1H NMR (500 MHz, CDCl3) δ7.41-7.26 (m, 5H), 5.36 (t, J=2.5 Hz, 1H), 5.11 (t, J=2.5 Hz, 1H), 4.77 (d, J=12.0 Hz, 1H), 4.62 (d, J=12.5 Hz, 1H), 4.18-4.14 (m, 2H), 4.05 (dd, J=4.5 and 12.0 Hz, 1H), 3.78 (dd, J=8.0 and 12.0 Hz, 1H), 2.90-2.88 (m, 1H), 1.08-0.97 (m, 27H); 13C NMR (125 MHz, CDCl3) δ 147.3, 138.1, 128.4, 127.6, 127.5, 111.1, 80.2, 74.2, 71.2, 71.1, 64.9, 50.1, 17.6, 17.5, 17.4, 17.3, 17.2, 17.1, 17.0. Anal. Calcd. for C26H44O5Si2: C, 63.37; H, 9.00. Found: C, 63.64; H, 9.05.
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