Nickel‐Catalyzed Synthesis of Structurally Diverse N‐(hetero)aryl Pyrroles

Pyrrole is an important five‐membered aromatic nitrogen compound found in various pharmaceuticals and natural products, including functional materials. Many methods have been developed to create substituted pyrroles. Nevertheless, the structurally diverse synthesis of N‐substituted pyrroles is less documented. Herein, we describe a simple procedure for the preparation of functionalized pyrroles employing 2,5‐hexandione and anilines as starting materials in the presence of a well‐defined homogeneous nickel catalyst (NiCl₂·6H₂O + dppe). Sensitive functional groups in anilines, such as halogen (F, Cl, Br, and I), ester, nitrile, and sulfur moieties, were well‐tolerated and yielded a diverse array of N‐(hetero)aryl pyrroles in high yields (50%–95%). These results were relatively challenging to achieve with previous methods. The reaction also occurs efficiently with succinaldehyde to yield a series of desired N‐aryl pyrrole skeletons.