Recent Progress in the Synthesis of 5-Unsubstituted Pyrrolidines via [3+2] Cycloadditions

The 1,3-dipolar cycloaddition of azomethine ylides with alkenes is one of the most powerful methods for the synthesis of multisubstituted pyrrolidines. 5-Unsubstituted pyrrolidines are important structural motifs of numerous biologically active natural products and drugs. Herein, recent progress in the synthesis of 5-unsubstituted pyrrolidines through intermolecular [3+2] cycloaddition is highlighted. 1 Introduction 2 Recent Development with α-Silylimines as Azomethine Ylide Precursors 3 Two-Step Protocol with α-Iminonitriles as Azomethine Ylide Precursors 4 Applications to Total Synthesis 5 Summary