[Br-].[CH3:2][O:3][C:4]1[CH:9]=[CH:8][C:7]([CH2:10][P+](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)=[CH:6][CH:5]=1.[CH:30]([C:33]1[CH:34]=[C:35]([CH:39]([CH3:43])[CH2:40][CH:41]=O)[CH:36]=[CH:37][CH:38]=1)([CH3:32])[CH3:31].CC(O)=O>C1COCC1>[CH:30]([C:33]1[CH:38]=[CH:37][CH:36]=[C:35]([CH:39]([CH2:40][CH:41]=[CH:10][C:7]2[CH:6]=[CH:5][C:4]([O:3][CH3:2])=[CH:9][CH:8]=2)[CH3:43])[CH:34]=1)([CH3:32])[CH3:31]Potassium t-butylat (17.1 mL, 17.1 mmol, 1.0 equiv., 1M in THF) was added to a solution of (4-methoxyphenyl)methyltriphenylphosphonium bromide (7.90 g, 17.1 mmol, 1.0 equiv.) in THF (17 mL) at 25° C. After the dark red suspension was stirred at 25° C. for 10 min, 3-(3-isopropylphenyl)butanal (3.24 g, 17.1 mmol, 1.0 equiv.) in THF (8.5 mL) was added, and the mixture was stirred at 25° C. 12 h. After addition of 20% aq. AcOH-solution at 25° C., the aqueous layer was extracted with hexane. The combined organic phases were washed with MeOH/H2O (4:1; 2-3x), dried (MgSO4), filtered and the filtrate was concentrated. The residue was purified by flash chromatography on SiO2 (cyclohexane/EtOAc 995:5→99:1) to yield 4.03 g (80%) of the title compound as a light yellow oil.
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