The N—N bond is widely found in natural products and bioactive compounds. The atropisomerism of N—N bond, however, has been dismissed for a long time due to the stereotype that N—N axis is unstable. The electronic barrier stemming from the repulsive interaction between the lone pairs on the two nitrogen atoms leads to a rotationally hindered axis, resulting in stable N—N atropisomers. Since the first report in 2021, the catalytic asymmetric synthesis of N—N atropisomers has been developed rapidly into an emerging area. These reactions include asymmetric N—H bond functionalization, asymmetric desymmetrization and atroposelective de novo construction of (hetero-)aromatic rings. The N—N axially chiral compounds are valuable molecules, in terms of their potential application in chiral ligand/catalysts design and biological activity evaluation. Herein, the state-of-the-art catalytic asymmetric synthesis of N—N atropisomers is summarized.

Key words: N—N bond, atropisomer, catalytic asymmetric synthesis