Propiolic Acids in the Synthesis of N-heterocycles

Abstract

Abstract: This review discussed the synthetic applications of propiolic acids in the preparation of diverse N-heterocycles. 3~9-membered rings like azirines, β-lactams, oxazolidin-2-ones, 2-oxindoles, indoles, isoindolin-1-ones, imidazo[1,2-a]pyridines, triazoles, 2-pyridones, 2-quinolones, 1,4- benzothiazines, thiazinones, spiroindolines, etc. could be constructed via radical addition, fourcomponent Ugi reactions, 1,3-dipolar cycloadditions, or Diels-Alder reaction mechanism. We hope this review will promote future research in this area: Introduction; Synthesis of azirines; Synthesis of lactams; Construction of five-membered rings; Construction of six-membered rings; Double cyclization for N-heterocycles; Construction of 7~9- membered rings; Conclusion.