Hydrochloric Acid → 3-tert-Butyl-1-ethylcyclopenta-1,3-diene

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Reaction Steps

To a 300 ml three-neck flask equipped with a magnetic stirrer chip and a three-way cock, 200 ml of dehydrated diethyl ether and 52 ml (154 mmol) of diethyl ether solution of 3.0 M ethyl magnesium bromide were charged under a nitrogen atmosphere. In the ice and water bath, 17.8 g (129 mmol) of 3-tert-butylcyclopentenone was added dropwise over 1 hour. The resultant solution was stirred at room temperature for 20 hours, and then the reaction solution was poured into 100 ml of 2N hydrochloric acid. The organic layer was separated, and the aqueous layer was extracted twice with 50 ml of ether. The obtained organic layers were combined, washed twice with a saturated aqueous solution of sodium hydrogencarbonate, twice with water, and twice with saturated brine, and dried over magnesium sulfate and distilled off the solvent under reduced pressure. Thereafter, the resulting product was purified by column chromatography to obtain 20.2 g (GC purity 75%) of a pale yellowy transparent solution. The yield was 78%. Identification was done by 1H-NMR spectrum. The measurement results are shown as follows.

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