N-Unsubstituted 3,4-difluoropyrrole is synthesized via a thermal [2+3] cycloaddition reaction of a N-tert-butyl 2-alkoxycarbonyl aziridine and chlorotrifluoroethylene. Dealkylation of an intermediate N-tert-butylpyrrole is obtained with trifluoromethanesulfonic acid.
LEROY, J.;RUBINSTEIN, M.;WAKSELMAN, C., J. FLUOR. CHEM., 1984, 25, N 2, 255-258