Tandem Intermolecular–Intramolecular Michael Addition of Bifunctional Hetero Nucleophiles to Polyfluoro-2-alkynoic Acids. Facile Synthesis of Polyfluoroalkylated Azaheterocycles

Polyfluoro-2-alkynoic acids, Rf–C≡C–COOH (1a—c: a, Rf = CHF2; b, Rf = CF3; c, Rf = CHF2CF2CF2), readily underwent an intermolecular–intramolecular Michael addition reaction with a variety of bifunctional azanucleophiles, such as RNHCH2CH2XH (R = H, Me; X = NH, S, O, NMe) and o-phenylenediamine, to give the corresponding carboxylated and/or decarboxylated 2-(polyfluoroalkyl)imidazolidine, thiazolidine, and oxazolidine derivatives in moderate to good yields.