Hydrochloric Acid → t-Butyl 3-(1-carboxycyclopentyl)propanoate

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Reaction Steps

To a 50 ml round-bottomed flask under nitrogen was added lithium diisopropylamide (10.95 mL, 21.90 mmol). The solution was cooled to −20° using a controlled dry ice/acetonitrile bath. Cyclopentanecarboxylic acid (1.187 mL, 10.95 mmol) in dry THF (10 mL) was added over 5 minutes, keeping the temperature at −20° C. The mixture was warmed to room temperature, stirred for one hour, then cooled to −78° C. Tert-butyl acrylate (1.685 mL, 10.95 mmol) in dry THF (10 mL) was added dropwise over 5 min, keeping the temperature at −70° C. After 2 hours at −70° C., the mixture was quickly warmed to 0° C., acidified with 5N HCl, and extracted with hexane. The hexane extract was washed with water and saturated sodium bicarbonate, water, and dried over MgSO4, and then recrystallized from hexanes. Recovered 1-(3-tert-butoxy-3-oxopropyl)cyclopentanecarboxylic acid (1.8 g, 7.43 mmol, 67.8% yield).

Provenance & Evidence