Trifluoroacetic acid → 2,2,2-Trifluoro-1-[3-(2-methoxy-benzyl)-azetidin-1-yl]-ethanone

Participants

Reaction Steps

To a solution of 3-(2-methoxy-benzyl)-azetidine-1-carboxylic acid tert-butyl ester (370 mg, 1.3 mmol) in DCM (10 mL) was added TFA (3 mL). After stirring for 16 h, TLC analysis indicated complete consumption of the starting material. To quench the reaction, saturated NaHCO3 solution and EtOAc were added. The aqueous portion was extracted twice with EtOAc and the combined organic extracts were dried (Na2SO4) and concentrated. To a solution of this material in DCM (20 mL) was added triethylamine (370 μL, 2.60 mmol) followed by trifluoroacetic anhydride (204 μL, 1.50 mmol). After 1 h, saturated NaHCO3 solution and EtOAc were added. The aqueous portion was extracted twice with EtOAc and the combined organic extracts were dried (Na2SO4) and concentrated to provide the title compound (274 mg, 75%). MS (ESI): mass calcd. for C13H14F3NO2, 273.1; m/z found, 274.2 [M+H]+. 1H NMR (CDCl3): 7.26-7.20 (m, 1H), 7.07 (dd, J=7.4, 1.6 Hz, 1H), 6.94-6.82 (m, 2H), 4.41 (dd, J=9.6, 8.4 Hz, 1H), 4.23-4.14 (m, 1H), 4.12-4.08 (m, 1H), 3.93-3.84 (m, 1H), 3.82 (s, 3H), 3.18-3.00 (m, 1H), 2.95-2.91 (m, 2H).

Provenance & Evidence