Tetrahydrofuran → 4-tert-butoxycarbonyl-2-bromo-4H-furo[3,2-b]pyrrole-5-carboxylic acid methyl ester

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Reaction Steps

To a solution of 4-tert-butoxycarbonyl-4H-furo[3,2-b]pyrrole-5-carboxylic acid methyl ester (100 mg, 0.38 mmol) in DCM (1 mL) was added a solution of TBAF in THF (1.0 M, 0.57 ml, 0.57 mmol) followed by the addition of NBS (87 mg, 0.49 mmol). The resulting mixture was stirred at rt overnight. The reaction mixture was diluted with DCM (10 mL), washed with 10 mL of water and then with 10 mL of brine and dried with Na2SO4. The solid was removed by filtration. The filtrate was concentrated by evaporation. The crude product was purified by chromatography (0-20% EtOAc in hexane) to give 85 mg of 4-tert-butoxycarbonyl-2-bromo-4H-furo[3,2-b]pyrrole-5-carboxylic acid methyl ester (85 mg, 65%). 1H NMR (400 MHz, CDCl3) δ (ppm) 6.81 (s, 1H), 6.61 (s, 1H), 3.83 (s, 3H), 1.59 (s, 9H).

Provenance & Evidence