[OH:1][C:2]1[CH:7]=[C:6]([F:8])[CH:5]=[CH:4][C:3]=1[CH2:9][CH2:10][C@H:11]([OH:22])[C@@H:12]([O:14][Si:15]([C:18]([CH3:21])([CH3:20])[CH3:19])([CH3:17])[CH3:16])[CH3:13].[CH2:23](Br)[C:24]1[CH:29]=[CH:28][CH:27]=[CH:26][CH:25]=1.C(=O)([O-])[O-].[K+].[K+]>CN(C=O)C.CCOC(C)=O>[CH2:23]([O:1][C:2]1[CH:7]=[C:6]([F:8])[CH:5]=[CH:4][C:3]=1[CH2:9][CH2:10][C@H:11]([OH:22])[C@@H:12]([O:14][Si:15]([C:18]([CH3:21])([CH3:20])[CH3:19])([CH3:16])[CH3:17])[CH3:13])[C:24]1[CH:29]=[CH:28][CH:27]=[CH:26][CH:25]=1(3S,4S)-1-(2-hydroxy-4-fluorophenyl)-4-tert-butyldimethylsilyloxy-3-pentanol (0.94 g) was treated with benzyl bromide (0.48 ml) and potassium carbonate (0.53 g) in DMF (5 ml) at room temperature for 2 hr. The mixture was diluted with EtOAc and washed with water twice, dried and evaporated. The residual oil (1.43 g) was chromatographed over silica gel (30 g), eluting with a mixture of hexane and EtOAc (40:1) to give a second crop of colorless oil of (3S,4S)-1-(2-benzyloxy-4-fluorophenyl)-4-tert-butyldimethylsilyloxy-3-pentanol (0.79 g, total yield 81.4%).
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