Hydrochloric Acid → Cyclohexanecarboxylic acid, 2,2-dimethyl-6-methylene-, methyl ester

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Reaction Steps

A solution of methyl 2,6,6-trimethyl-cyclohex-1-ene-carboxylate (80.0 g) in tetrahydrofuran (THF, 640 ml), contained in a 1.5 l flask equipped with a mechanical strirrer and a nitrogen inlet, was deprotonated by adding, between -10° and 0°, a solution of butyllithium in hexane (411 ml of a 1.5M solution). Once the addition was completed, the reaction was allowed to proceed at 15°-17° for 10 min. The temperature was reduced to -30° and trimethylsilyl chloride (143.35 g) was added to the reaction mixture over half an hour, while maintaining the temperature at 10° or below. The temperature was allowed to increase to 20° and the reaction mixture was poured on 5% HCl. After stirring for 10 min, the mixture was extracted with ether and the organic phase was washed with saturated aqueous solutions of NaHCO3 and NaCl, dried over Na2SO4, filtered and the solvents evaporated. After distillation on a column filled with inox helices and equipped with a total reflux top, two fractions of a crude product were obtained.

Provenance & Evidence