Carbon Dioxide → 5-tert-butylfuran-2-carboxylic Acid

Temperature

0 °C

To a solution of 2-tert-butylfuran (4.5 g, 36 mmol) in anh. THF (60 mL) at −78° C. under N2 was added n-butyllithium (1.6M in hexane, 25 mL, 40 mmol, 1.1 equiv) dropwise. After 30 min, the cooling bath was replaced with an ice bath and the mixture was stirred at 0° C. for 1 h. Dry CO2, generated from dry ice and dried over an anhydrous Na2SO4 tower, was bubbled into the reaction mixture over 20 min at −78° C. and then at 0° C. The reaction mixture was acidified to pH 1 with a 1M HCl solution, then extracted with EtOAc. The organic layer was washed with a concentrated NaCl solution, dried (NaSO4) and concentrated under reduced pressure to give 5-tert-butylfuran-2-carboxylic acid as a pale yellow solid (4.2 g, 69%): 1H NMR (CDCl3) δ1.29 (s, 9H), 6.11 (d 1H, J=3.3 Hz), 7.19 (d, 1H, J=3.3 Hz), 11.0 (br s, 1H).

1. customthe cooling bath was replaced with an ice bath
2. dry with materialdried over an anhydrous Na2SO4 tower
3. customwas bubbled into the reaction mixture over 20 min at −78° C.
4. customat 0° C
5. extractionextracted with EtOAc
6. washThe organic layer was washed with a concentrated NaCl solution
7. dry with materialdried (NaSO4)
8. concentrationconcentrated under reduced pressure

ORD record

ord-53c64cef308c4a8a83b229a7c97dff1c

Source dataset

uspto-grants-2002_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06344476B1