O[CH2:2][C:3]1[CH:8]=[CH:7][C:6](/[CH:9]=[CH:10]/[C:11]([O:13][CH2:14][CH3:15])=[O:12])=[C:5]([CH3:16])[CH:4]=1.C(Br)(Br)(Br)[Br:18].C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.ClCCl.O>ClCCl>[Br:18][CH2:2][C:3]1[CH:8]=[CH:7][C:6](/[CH:9]=[CH:10]/[C:11]([O:13][CH2:14][CH3:15])=[O:12])=[C:5]([CH3:16])[CH:4]=1A solution of ethyl(2E)-3-[4-(hydroxymethyl)-2-methylphenyl]prop-2-enoate (intermediate 19, 1.389 g) in dry dichloromethane (40 ml) was cooled to 0° C. and treated with carbon tetrabromide (2.3 g) followed by, in small portions, triphenylphosphine (1.82 g). The resulting solution was stirred thus overnight, then poured into dichloromethane/water and the organic phase separated and washed with more water, brine and dried over sodium sulfate then evaporated in vacuo. The isolated product was further purified by flash column chromatography using cyclohexane:ethyl acetate (9:1) as an eluent which gave the title compound as a white solid.
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