Coplanar Atropochiral 5H‐Cyclopenta[2,1‐b:3,4‐b']dipyridine Ligands: Synthesis and Applications in Asymmetric Ring‐Opening Reaction

Bipyridines represent a class of ligands renowned for their versatility and efficacy in numerous transition metal‐catalyzed reactions. Chiral bipyridine ligands are noted for their distinctive reactivity and stereoselectivity. In this work, we have designed and synthesized a class of bipyridine ligands endowed with an axially chiral scaffold. These ligands feature: (a) a precisely aligned coplanar bipyridine framework that is beneficial for metal chelation; (b) a spacious environment around the metal‐bipyridine complexes, capable of hosting substrates with substantial steric bulk; (c) a chiral pocket induced by the axially chiral architecture. These atropochiral planar bipyridine ligands were successfully applied in copper‐catalyzed ring‐opening reactions of cyclic diaryliodoniums with bulky secondary amines, achieving high efficiency and stereoselectivity that were unsuccessful in our previous efforts.