p-Toluenesulfonic acid → Ethyl 3-(4-cyclopentylphenyl)but-2-enoate

反応式

O[C:2]([C:10]1[CH:15]=[CH:14][C:13]([CH:16]2[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+]>[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]1

参加物

実験手順

To a solution of ethyl 3-hydroxy-(4′-cyclopentylphenyl)-butanoate (2a, 12 g) in benzene (150 ml) was added p-toluenesulfonic acid and refluxed for 1 h. The mixture was diluted with sat. NaHCO3 (100 ml) and organic layer was separated. The organic phase was washed with water, dried (Na2SO4) and concentrated. The crude product was purified by column chromatography on silica gel to give 8.9 g (79.4% yield) of ethyl 3-(4-cyclopentylphenyl)-but-2-enoate (3a, formula 3, R=cyclopentyl) as oil.