Imidazoline‐Proline and Imidazoline‐Prolinate Ligands for Copper‐Catalyzed Asymmetric <i>Exo</i> ‐Selective [3 + 2] Cycloaddition of Iminoesters with Nitroalkenes

Diphenylethylenediamine‐derived imidazoline‐amino acid derivatives are designed as nonphosphine chiral nitrogen ligands for metal‐catalyzed exo ‐selective [3 + 2] cycloaddition reaction of iminoesters with nitroalkenes. The newly developed ( R , R )‐imidazoline‐L‐proline and t ‐butyl prolinate‐Cu(OTf) 2 complexes afford the exo ‐pyrrolidine adducts with up to 99% ee.