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.