[CH2:1]([Si:3](Cl)([CH2:6][CH3:7])[CH2:4][CH3:5])[CH3:2].[CH2:9]([O:11][C:12]([C@@H:14]1[CH2:18][C:17]([C:19]2[CH:24]=[CH:23][C:22]([CH3:25])=[CH:21][N:20]=2)=[C:16]([CH3:26])[C@H:15]1[OH:27])=[O:13])[CH3:10].N1C=CN=C1>C(Cl)Cl>[CH2:9]([O:11][C:12]([C@@H:14]1[CH2:18][C:17]([C:19]2[CH:24]=[CH:23][C:22]([CH3:25])=[CH:21][N:20]=2)=[C:16]([CH3:26])[C@H:15]1[O:27][Si:3]([CH2:6][CH3:7])([CH2:4][CH3:5])[CH2:1][CH3:2])=[O:13])[CH3:10]Triethylsilyl chloride (145 μL, 0.863 mmol, 1.5 equiv) was added dropwise to a solution of alcohol 88 (150 mg, 0.575 mmol) and imidazole (17 mg, 1.72 mmol, 3 equiv) in methylene chloride (4 ml) at 0° C. After stirring at 0° C. for 2 hr, the reaction was quenched with water (2.5 ml), and extracted with ethyl acetate (3×5 ml). The organic extracts were washed with brine (3.5 ml), and dried over anhydrous sodium sulfate. Filtration and evaporation of the solvents in vacuo furnished an oily crude product which was purified by flash column chromatography on silica (2-7% EtOAc/hexanes-) to give 93 (198 mg, 92%) as a yellow oil: [α]22D=−51.04 (c=0.7, CHCl3); TLC Rf=0.29 (silica gel, 25% EtOAc/hexanes); 1H NMR (600 MHz, CDCl3) δ 8.41 (s, 1H), 7.45-7.42 (dd, 1H, 3J=1.8 Hz, 2J=8.4 Hz), 7.2-7.18 (d, 1H, 3J=7.8 Hz), 5.12 (d, 1H, 3J=4.8 Hz), 4.2-4.16 (dd, 2H, 3J=7.2 Hz, 2J=14.4 Hz), 3.17-3.12 (m, 1H), 3.0-2.89 (m, 2H), 2.3 (s, 3H), 1.97 (s, 3H), 1.29-1.26 (t, 3H, 3J=14.4 Hz), 0.98-0.95 (t, 9H, 3J=7.8 Hz), 0.67-0.63 (q, 6H, 3J=7.8 Hz); 13C NMR (100 MHz, CDCl3) δ 175.31, 153.31, 149.87, 139.09, 136.51, 134.07, 131.15, 122.39, 84.53, 60.83, 51.58, 37.40, 18.42, 14.46, 13.31, 7.03, 5.15; HRMS calcd for C21H33NO3Si+H+376.2308; found 376.2302 [M+H+].
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