Catalytic Asymmetric Synthesis of N—N Atropisomers
Tingyu Song, Ran Li, Lihua Huang, Shi‐Kun Jia, Guang‐Jian Mei
Abstract
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.