O[C:2]([C:10]1[CH:15]=[CH:14][C:13]([CH:16]2[CH2:23][CH2:22][CH2:21][CH2:20][CH2:19][CH2:18][CH2:17]2)=[CH:12][CH:11]=1)([CH3:9])[CH2:3][C:4]([O:6][CH2:7][CH3:8])=[O:5].C1(C)C=CC(S(O)(=O)=O)=CC=1>C1C=CC=CC=1.C([O-])(O)=O.[Na+].O>[CH:16]1([C:13]2[CH:12]=[CH:11][C:10]([C:2]([CH3:9])=[CH:3][C:4]([O:6][CH2:7][CH3:8])=[O:5])=[CH:15][CH:14]=2)[CH2:17][CH2:18][CH2:19][CH2:20][CH2:21][CH2:22][CH2:23]1To a solution of ethyl 3-hydroxy-3-(4′-cyclooctylphenyl)-butanoate (2d, 36 g) in benzene (350 ml) was added p-toluenesulfonic acid and refluxed for 2.5 h. The mixture was diluted with saturated NaHCO3 solution (20 ml) and water (50 ml) and benzene layer was separated out. Aqueous layer was extracted with benzene (2×200 ml) combined organic layer was washed with water (2×20 ml), dried over Na2SO4 and concentrated. Crude product was purified by column chromatography to furnish 27.5 g (81.1% yield) of ethyl 3-(4′-cyclooctylphenyl)-but-2-enoate (3d, formula 3, R=cyclooctyl) as oil.
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