Carbon Dioxide → 5-Methoxythiophene-2-carboxylic acid

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Reaction Steps

2-(methyloxy)thiophene (1.01 g, 8.85 mmol) was added slowly over 15 min to a 100 mL round-bottomed flask containing 2.5M nBuLi in hexanes (3.8 mL, 9.50 mmol) in Tetrahydrofuran (THF) (40 mL) at −78° C. After warming to room temperature and stirring for 2 h, the mixture was cooled to −35° C. and crushed solid CO2 was added. The mixture warmed to room temperature over 3 hours and was cooled in an ice bath and quenched with NH4Cl(sat.). The cold reaction mixture was partitioned between CHCl3/H2O, the aqueous layer was made acidic with 6N HCl. The separated organic layer was dried with Na2SO4 and concentrated affording the title compound (1.3 g, 8.05 mmol, 91%) which was used without further purification: LC-MS (ES) m/z=159 (M+H)+.

Provenance & Evidence