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

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Reaction Steps

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

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