Citric Acid → (RS)-2-methyl-4-methylidene-3-ethyl-2-cyclopenten-1-yl (1R)-trans-2,2-dimethyl-3-(2-methyl-1-propenyl)cyclopropanecarboxylate

Participants

Reaction Steps

540 mg of (1R)-trans-2,2-dimethyl-3-(2-methyl-1-propenyl)cyclopropanecarboxylic acid chloride was added under ice-water cooling to a mixed solution of 400 mg of (RS)-2-methyl-4-methylidene-3-ethylcyclopent-2-en-1-ol, 5 mg of 2,6-di-t-butyl-4-methylphenol and 274 mg of pyridine in 6 ml of toluene. The reaction was allowed to react at an ambient temperature for eight hours. The reaction solution was added to a 5% citric acid solution under ice-water cooling and extracted three times with diethyl ether. The combined ether layer was washed successively with a saturated sodium hydrogencarbonate solution and a saturated sodium chloride solution and dried over anhydrous magnesium sulfate. After removal of the solvent under reduced pressure, the obtained residue was subjected to silica gel column chromatography to yield 751 mg of (RS)-2-methyl-4-methylidene-3-ethyl-2-cyclopenten-1-yl (1R)-trans-2,2-dimethyl-3-(2-methyl-1-propenyl)cyclopropanecarboxylate (Compound No.1). Yield 72% (Eluent: n-hexane/ethyl acetate=30/1, 2,6-di-t-butyl-4-methylphenol 0.1%) nD20.5 1.5070

Provenance & Evidence