Water → 2-Tert-butoxycarbonylamino-3-difluoromethoxy-butyric acid methyl ester

Participants

Reaction Conditions

Reaction Steps

To a mixture of 2-tert-butoxycarbonylamino-3-hydroxy-butyric acid methyl ester (630 mg, 2.70 mmol) and copper(I) iodide (105 mg, 0.55 mmol) in acetonitrile at 45° C. was added a solution of 2-(fluorosulfonyl)difluoroacetic acid (0.560 mL, 5.42 mmol) in acetonitrile (2 mL) by syringe pump over 45 minutes. The reaction was then stirred at 45° C. for 30 minutes. Another solution of 2-(fluorosulfonyl)difluoroacetic acid (0.560 mL, 5.42 mmol) in acetonitrile (2 mL) was added by syringe pump over 45 minutes at 45° C. The reaction was stirred for 30 minutes at 45° C. after the second syringe pump addition was complete. Water was carefully added to quench the reaction, and the mixture was diluted with ethyl acetate. The organic layer was separated, washed with water and brine, dried (MgSO4) and concentrated. The crude material was purified by flash chromatography (10% ethyl acetate/hexanes) to yield 2-tert-butoxycarbonylamino-3-difluoromethoxy-butyric acid methyl ester (276 mg, 36%). 1H-NMR: 400 MHz, (CDCl3: 6.16 (t, JHF=74.0 Hz, 1H), 5.23-5.16 (br, 1H), 4.86-4.80 (m, 1H), 4.40 (br d, J=9.8 Hz, 1H), 3.76 (s, 3H), 1.46 (br s, 9H), 1.36 (d, J=6.4 Hz, 3H) ppm.

Provenance & Evidence