Transition Metal-Catalyzed and Metal-Free Cyclization Reactions of Alkynes with Nitrogen-Containing Substrates: Synthesis of Pyrrole Derivatives

This review describes the efforts in the synthesis of pyrrole derivatives using the reaction of alkynes with nitrogen-compounds under transition metal-catalyzed and metal-free conditions, in the past decade. We initially focused on the methods of preparation of pyrrole derivatives using reactions catalyzed by transition metal. In this part, we described the syntheses of 1-pyrrolines, 2-pyrrolines, 3-pyrrolines, pyrroles, and pyrrolidines following an alphabetical order of the transition metal used for the synthesis. Subsequently, we presented the synthesis of these pyrrole derivatives under metal-free conditions.