N‑Heterocyclic Carbene-Catalyzed Atroposelective Synthesis of Pyrrolo[3,4‑b]pyridines with Configurationally Stable C–N Axial Chirality

The first atroposelective synthesis of pyrrolo­[3,4-b]­pyridines catalyzed by N-heterocyclic carbene has been achieved. A wide range of chiral atropisomers of pyrrolo­[3,4-b]­pyridines were obtained in high yields with excellent enantioselectivities (96–99% enantiomeric excess). The experimental results and density functional theory calculations showed that the C–N axial chirality of the product had high thermal stability.