N—N单键阻转异构体的催化不对称合成

Catalytic Asymmetric Synthesis of N—N Atropisomers

N—N单键广泛存在于天然产物和生物活性化合物中.然而,由于N—N轴不稳定的刻板印象,N—N单键的阻转异构现象长期以来被忽视.事实上,N—N单键两端氮原子上的孤对之间存在排斥相互作用,即电子能垒.该电子能垒会导致N—N单键的旋转受阻,从而产生稳定的N—N阻转异构体.自2021年首次被报道以来,催化不对称合成N—N阻转异构体迅速发展成为一个新兴领域.这些反应包括不对称的N—H键功能化、不对称的去对称化和(杂)芳香烃环的阻转异构选择性从头构建.综述了N—N单键阻转异构体催化不对称合成的最新进展.

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.