Aziridines in Formal [3+2] Cycloadditions: Synthesis of Five-Membered Heterocycles

Chemistry based on ring opening of aziridines has been widely studied in organic synthesis. However, it has mainly been centered on ring opening by nucleophiles and on cycloaddition of azomethine ylides generated by carbon–carbon bond cleavage. In recent years, significant effort has been dedicated to study of the participation of aziridines in formal [3+2] cycloadditions, which provide routes for the construction of a wide variety of functionalized five‐membered heterocycles. Here we review the most relevant aspects of the reactivities and selectivities of aziridines as masked zwitterionic 1,3‐dipoles generated through C–N bond cleavage. Aziridines participate in formal [3+2] cycloadditions as masked zwitterionic 1,3‐dipoles, generated through C–N bond cleavage, providing routes for the construction of a wide variety of functionalized five‐membered heterocycles.