Diversity oriented synthesis of cyano-substituted polycyclic N-heteroaryl compounds in green solvent

Cyanated polycyclic N-heterocycles are vital for pharmaceutical applications; however, their synthesis often relies on unsustainable methods involving non-green solvents, stoichiometric chemical oxidants or mediators, or precious-metal catalysts. In this study, we report a manganese-catalyzed oxidative tandem reaction for synthesizing cyanated polycyclic N-heterocycles from arylacetic acids/aromatic aldehydes, heterocyclic amines, and trimethylsilyl cyanide. This tandem reaction proceeds via a manganese-catalyzed Strecker reaction, followed by oxidative radical cyclization, and aromatization. Notably, this protocol utilizes γ-valerolactone as a green solvent, both Mn catalyst and γ-valerolactone can be recycled multiple times.