[CH2:1](Br)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.[Br:9][C:10]1[CH:15]=[CH:14][C:13]([CH2:16][C@H:17]([OH:22])[C:18]([O:20][CH3:21])=[O:19])=[CH:12][CH:11]=1>C(OCC)C.[Ag]=O>[Br:9][C:10]1[CH:11]=[CH:12][C:13]([CH2:16][C@H:17]([O:22][CH2:1][C:2]2[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=2)[C:18]([O:20][CH3:21])=[O:19])=[CH:14][CH:15]=11.9 ml (16 mmol) of benzyl bromide are added to a mixture of 4.4 g (19 mmol) of silver oxide and 3.5 g (13 mmol) of methyl (S)-3-(4-bromophenyl)-2-hydroxypropionate in 20 ml of diethyl ether. The reaction mixture is stirred at 50° C. for 12 hours. The mixture is filtered and then the solvents are evaporated. The residue is chromatographed on silica gel (heptane/ethyl acetate 80/20). 4 g of methyl (S)-3-(4-bromophenyl)-2-benzyloxypropanoate are obtained in the form of an oil. Yield=85%.
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