Carbon Dioxide → 3-((tert-Butoxycarbonyl)amino)furan-2-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

Butyl lithium (as 1.6 M in hexanes, 45 mL) was added slowly to a solution of tert-butyl 3-furylcarbamate (Intermediate 80) (5.49 g) in THF (60 mL) at −40° C., keeping the internal reaction temperature less than −35° C. The reaction was stirred at −40° C. for 4 hours, then poured onto solid CO2 (100 mL) under a blanket of diethyl ether (300 mL). After warming to ambient temperature, the mixture was poured into water (300 mL) with stirring and an additional 100 mL diethyl ether added. The phases were separated and the organic phase was further extracted into water (2×100 mL). The combined organic phases were washed with ether, acidified by addition of aqueous HCl, and extracted into EtOAc (4×250 mL). The combined extracts were dried and evaporated to give a pale yellow solid (7.5 g). This was triturated with cyclohexane to afford the title compound as a white solid (4.80 g, 70%);

Provenance & Evidence