Formaldehyde → 2-(cis-4-Tert-butoxycarbonylamino-cyclopent-2-enylmethyl)-acrylic acid ethyl ester

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Reaction Steps

Diethyl amine (0.31 mL; 3.0 mmol) was added to a mixture of 2-(cis-4-tert-butoxycarbonylamino-cyclopent-2-enylmethyl)-malonic acid monoethyl ester (0.66 g, 2.0 mmol) in 36% aqueous solution of formaldehyde (0.25 mL, 3.2 mmol), CH2Cl2 (1.6 mL) and water (1.6 mL) at 0° C. The reaction mixture was stirred at room temperature overnight, poured onto ice-water (400 mL) and extracted with CH2Cl2. During the extraction, phase separation was improved by the addition of brine. The combined organic phases were washed with 5% NaHCO3, dried and concentrated under reduced pressure to yield 2-(cis-4-tert-butoxycarbonylamino-cyclopent-2-enylmethyl)-acrylic acid ethyl ester (0.56 g, 94%) as an oil.

Provenance & Evidence