[CH2:1]([O:8][C:9]1[CH:10]=[C:11]([C:15]([CH2:17][C:18]2[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=2)=[O:16])[CH:12]=[CH:13][CH:14]=1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.CC(C)([O-])C.[K+].Br[CH2:31][C:32]([O:34][CH3:35])=[O:33]>O1CCCC1>[CH2:1]([O:8][C:9]1[CH:10]=[C:11]([C:15](=[O:16])[CH:17]([C:18]2[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=2)[CH2:31][C:32]([O:34][CH3:35])=[O:33])[CH:12]=[CH:13][CH:14]=1)[C:2]1[CH:3]=[CH:4][CH:5]=[CH:6][CH:7]=1A stirred solution of benzyl 3-benzyloxyphenyl ketone (3.02 g) in dry tetrahydrofuran (70 mL) at −40° C. is treated with potassium tert-butoxide (1.12 g), portionwise during 10 minutes. The reaction is stirred at −40° C. for 1 hour and is then treated dropwise with a solution of methyl bromoacetate (1.04 g) in tetrahydrofuran (10 mL). The mixture is allowed to stir at ambient temperature for 18 hours. After this time, the reaction is concentrated to dryness and partitioned between ethyl acetate and water. The organic layer is dried over magnesium sulphate and concentrated under reduced pressure. The residue is recrystallised from a mixture of ethyl acetate and pentane, to give methyl (RS)-4-(3-benzyloxyphenyl)-4-oxo-3-phenylbutanoate (1.4 g), m.p. 88-89° C.
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