[CH2:1]([O:8][C@@H:9]([CH3:12])[CH:10]=[O:11])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.[C:13]1([CH2:23][CH2:24]Br)[C:22]2[C:17](=[CH:18][CH:19]=[CH:20][CH:21]=2)[CH:16]=[CH:15][CH:14]=1.[Mg].C1COCC1>CCOCC.[Br-].[Zn+2].[Br-]>[CH2:1]([O:8][C@H:9]([C@@H:10]([OH:11])[CH2:24][CH2:23][C:13]1[C:22]2[C:17](=[CH:18][CH:19]=[CH:20][CH:21]=2)[CH:16]=[CH:15][CH:14]=1)[CH3:12])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1A solution of (S)-2-(benzyloxy)propanal (Bull. Chem. Soc. Jpn. (1989) 62, 3038, 16.25 g) in ether (200 ml) was added to a suspension of zinc bromide (26.75 g) in ether (50 ml) below 6° C. and then an ethereal solution of 2-(1-naphthyl)ethylmagnasium bromide, prepared from 2-(1-naphthyl)ethyl bromide (46.55 g) and magnesium turnings (9.63 g) in ether (300 ml), was added below 8° C. The mixture was stirred at 4° C. for 1 h and then THF (200 ml) was added. The final mixture was stirred overnight at room temperature. After cooling, the mixture was quenched with saturated aqueous ammonium chloride solution (200 ml) and insoluble material was filtered. The filtrate was extracted with ethyl acetate and the extract was washed with brine, dried and concentrated in vacuo. Flash chromatography (hexane:ethyl acetate =9:1) gave (2S,3S)-2-benzyloxy-5-(1-naphthyl)pentan-3-ol (9.78 g, 30.8%) as an oil.
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