1,3-Cyclohexanedione, 2-chloro-2-(2-propenyl)- → 2-Cyclopenten-1-one, 2-(2-propenyl)-

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Reaction Steps

Anhydrous powdered sodium carbonate (670 g) and 1300 ml of dry (alumina) xylene were placed in a 3-l., three-necked flask equipped with a Dean-Stark trap, condenser, vibra-mixer, dropping funnel and argon inlet. The flask was flushed with argon and the contents brought to reflux. A solution of 2-chloro-2-allyl-1,3-cyclohexanedione (147 g, 0.79 mol) in 200 ml of xylene was added dropwise at such a rate that strong refluxing was maintained. After 4.5 hr, the reaction was cooled, filtered, and the sodium carbonate cake washed thoroughly with ethyl acetate. Evaporation of the solvent and careful fractionization of the residual oil gave 47.8 g (50 percent) of 2-allyl-2-cyclopenten-1-one, bp 73°-84°/4.2 mm.

Provenance & Evidence