[CH2:1]([O:8][C@H:9]1[C@H:15]([O:16][CH2:17][C:18]2[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=2)[C@@H:14]([O:24][CH2:25][C:26]2[CH:31]=[CH:30][CH:29]=[CH:28][CH:27]=2)[C@:13]2([C:33]3[CH:38]=[CH:37][C:36]([Cl:39])=[C:35]([CH2:40][C:41]4[CH:46]=[CH:45][C:44]([O:47][CH2:48][CH3:49])=[CH:43][CH:42]=4)[CH:34]=3)[O:32][C@@:10]1([CH2:50]O)[CH2:11][O:12]2)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.C(N(S(F)(F)[F:58])CC)C>ClCCl>[CH2:1]([O:8][C@H:9]1[C@H:15]([O:16][CH2:17][C:18]2[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=2)[C@@H:14]([O:24][CH2:25][C:26]2[CH:31]=[CH:30][CH:29]=[CH:28][CH:27]=2)[C@:13]2([C:33]3[CH:38]=[CH:37][C:36]([Cl:39])=[C:35]([CH2:40][C:41]4[CH:46]=[CH:45][C:44]([O:47][CH2:48][CH3:49])=[CH:43][CH:42]=4)[CH:34]=3)[O:32][C@@:10]1([CH2:50][F:58])[CH2:11][O:12]2)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1To a solution of {(1S,2S,3S,4R,5S)-2,3,4-Tris-benzyloxy-5-[4-chloro-3-(4-ethoxy-benzyl)-phenyl]-6,8-dioxa-bicyclo[3.2.1]oct-1-yl}-methanol (616 mg, 0.871 mmol) in dichloromethane (3 mL) at 0 degrees Celsius was added diethylaminosulfur trifluoride (170 microL, 1.3 mmol) and the resulting mixture was slowly warmed to room temperature and stirred at this temperature for 16 hours. The mixture was diluted with dichloromethane and washed with a saturated solution of aqueous sodium bicarbonate, dried over sodium sulfate, filtered and concentrated in vacuo. The residue was purified by flash chromatography over silica gel using a 40 g redisep silica cartridge (eluting with a gradient of 0 to 20% ethyl acetate in heptane) to afford (1S,2S,3S,4R,5S)-2,3,4-tris-benzyloxy-5-[4-chloro-3-(4-ethoxy-benzyl)-phenyl]-1-fluoromethyl-6,8-dioxa-bicyclo[3.2.1]octane as a colorless oil (40 mg, 7% yield). (LCMS) 753.4 (M+HCOO−: negative mode).
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