[CH2:1]([O:3][C:4](=[O:22])[C:5]([CH3:21])([O:14][C:15]1[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=1)[CH2:6][C:7]1[CH:12]=[CH:11][C:10]([OH:13])=[CH:9][CH:8]=1)[CH3:2].[CH2:23](Br)[CH:24]=[CH2:25].C(=O)([O-])[O-].[K+].[K+]>C(C(C)=O)C>[CH2:1]([O:3][C:4](=[O:22])[C:5]([CH3:21])([O:14][C:15]1[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=1)[CH2:6][C:7]1[CH:12]=[CH:11][C:10]([O:13][CH2:25][CH:24]=[CH2:23])=[CH:9][CH:8]=1)[CH3:2]A solution of 3-(4-hydroxyphenyl)-2-methyl-2-phenoxy-propionic acid ethyl ester (500 mg, 1.67 mmol) in methyl ethyl ketone (6 mL) was treated with allyl bromide (232 mg, 1.92 mmol, 0.17 mL) and potassium carbonate (311 mg, 2.25 mmol) and then heated to reflux. After 18 h, the mixture was cooled to ambient temperature and then partitioned between ethyl acetate and water. The aqueous phase was extracted with ethyl acetate and then the organic phases were dried (MgSO4), filtered and concentrated under reduced pressure. The residue was purified by column chromatography (100 mL SiO2, hexanes to 10% ethyl acetate/hexanes) to provide the desired product (478 mg, 84%) as a clear, colorless oil: 1H NMR (400 MHz, CDCl3) δ 7.22 (t, J=8.0 Hz, 2H), 7.16 (d, J=8.8 Hz, 2H), 6.97 (dt, J=7.6, 1.2 Hz, 1H), 6.83 (d, J=7.8 Hz, 2H), 6.84 (t, J=8.4 Hz, 2H), 6.05 (ddd, J=17.2, 10.6, 5.2 Hz, 1H), 5.41 (dd, J=17.2, 1.6 Hz, 1H), 5.28 (dd, J=10.8, 1.4 Hz, 1H), 4.22 (d, J=5.2 Hz, 2H), 4.19 (q, J=6.8 Hz, 2H), 3.27 (A of AB, J=14 Hz, 1H), 3.11 (B of AB, J=14 Hz, 1H), 1.40 (s, 3H), 1.21 (t, J=6.8 Hz, 3H).
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