5-(5-Bromo-4-ethylphenyl)-4-hydroxycyclopent-2-enone → 2-(5-Bromo-2-ethylphenyl)cyclopent-4-ene-1,3-dione

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Reaction Steps

Jones' reagent (75 ml of 1.67 M solution, 125 mmol) is added dropwise over 30 minutes to a cooled (ice-bath) solution of 5-(5-bromo-4-ethylphenyl)-4-hydroxycyclopent-2-enone (33 g, 117 mmol) in acetone (400 ml). The mixture is stirred for 20 minutes, then the cooling bath is removed and the mixture is stirred for 1 hour at room temperature. Isopropanol (150 ml) is added to the yellow slurry and the mixture is stirred at room temperature for 2 hours. The mixture is diluted with ethyl acetate and washed with brine, dried over anhydrous magnesium sulfate, filtered and the filtrate is evaporated under reduced pressure to give 2-(5-bromo-2-ethylphenyl)cyclopent-4-ene-1,3-dione (32.17 g).

Provenance & Evidence