Photoredox catalyzed synthesis of indole-based azahelicenes

In recent years, photoredox catalysis has gained wide attention as an essential technique for the synthesis of heterocyclic structures. In particular, azahelicenes constitute a class of heteroaromatic molecules which are characterized by an extended conjugated system. These compounds find application in optoelectronics, catalysis, and sensors, due to their large conductivity and polarizability. In addition, their intrinsic helical chirality is reflected in high optical rotation. In light of this context and considering our group's continuous interest in the synthesis of polycyclic indoles, we are developing a method for the preparation of different benzo[c]carbazoles and indole-based azahelicenes under photoredox conditions. The key advantages of this innovative method are its broad applicability, good yields, selectivity, and gentle reaction conditions. In addition, the synthesis of indole-based azahelicenes from vinyl-indoles as starting precursors is here proposed for the first time.