Trifluoroacetic acid → 4,4-Difluoroproline

Participants

Reaction Steps

(S)-1-(tert-butoxycarbonyl)-4,4-difluoropyrrolidine-2-carboxylic acid (500 mg, 2.0 mmol) was dissolved in dichloromethane and treated dropwise with TFA (227 mg, 153 μL, 2 mmol). The reaction was stirred for 3 h at room temperature, the solvents evaporated to obtain (S)-4,4-difluoropyrrolidine-2-carboxylic acid, which was used in the next step without further purification. LC/MS: m/z 152.2 (M+H)+ at 0.53 min (10%-99% CH3CN (0.035% TFA)/H2O (0.05% TFA)).

Provenance & Evidence