Trifluoroacetic acid → Ethyl 1-benzyl-4-(1-tert-butoxycarbonylaminocyclopropyl)-3-pyrroline-3-carboxylate

Participants

Reaction Steps

N-Benzyl-N-(n-butoxymethyl)trimethylsilylmethylamine (2.006 g, 7.176 mmol) and ethyl 3-(1-tert-butoxycarbonylaminocyclopropyl)propiolate (1.136 g, 4.485 mmol) were dissolved in dry dichloromethane (9 ml). While stirring at room temperature, a 1.0 M solution of trifluoroacetic acid in dichloromethane (0.72 ml, 0.72 mmol) was added thereto and the liquid reaction mixture was stirred for 3 hours. Then a saturated aqueous solution of sodium bicarbonate (20 ml) was added to the liquid reaction mixture followed by extraction with dichloromethane (20 ml×3). The combined organic layer was washed with a saturated aqueous solution of sodium chloride (30 ml) and dried over anhydrous magnesium sulfate. After filtering, the filtrate was concentrated under reduced pressure and the residue was subjected to flash silica gel column chromatography (eluent: chloroform) to obtain 1.449 g (83.6%) of the title compound as a colorless oily substance.

Provenance & Evidence