tert-Butanol → Tert-butyl 5-(trifluoromethyl)thiophen-2-ylcarbamate

Participants

Reaction Conditions

Reaction Steps

To 5-(trifluoromethyl)thiophene-2-carboxylic acid in tBuOH (50 mL) was added triethylamine (1.53 mL, 11 mmol) and diphenylphosphoryl azide (DPPA) (2.4 mL, 11 mmol). This mixture was heated to 90° C., and was stirred overnight (ca. 16 hours). Thin layer chromatography (TLC) indicated that the reaction was complete. The solvent was removed under reduced pressure, the residue was dissolved in ethyl acetate (EtOAc) and washed 1× with NaHCO3 aq sat, 1× with citric acid (10% aqueous), and 1× brine. The solution was dried over MgSO4, filtered and concentrated. After silica gel chromatography (5 to 20% EtOAc/hexanes) the title compound was afforded (1.46 g, 44% over 3 steps) as a yellow/orange solid, mp 118-120° C.; Rf=0.31 (10% EtOAc/hex); 1H NMR (DMSO-d6) δ 11.03 (br s, 1H), 7.38 (app d, 1H, J=4.1 Hz), 6.51 (app d, 1H, J=3.3 Hz), 1.49 (s, 9H); GCMS (EI) m/z 267 (M+).

Provenance & Evidence