Cyclocarboamination of Alkynes with Aziridines: Synthesis of 2,3-Dihydropyrroles by a Catalyzed Formal [3 + 2] Cycloaddition

An efficient cyclocarboamination reaction of nonactivated alkynes with aziridines, catalyzed by Lewis or Bronsted acids, to form 2,3-dihydropyrroles through a formal [3+2] cycloaddition, is described. The reaction provides a wide range of polysubstituted dihydropyrroles in a highly regioselective manner, is scalable, proceeds under mild reaction conditions, and uses low catalyst loadings.