Electrosynthesis of Highly Functionalized Polycyclic N-Heteroaromatics through Cascade Radical Cyclization and Alkoxylation in Batch and Continuous-Flow

Electrochemical radical cascade cyclization has been recognized as a powerful, straightforward, and environmentally-friendly synthetic tool to give highly functionalized polycyclic aromatic compounds but remains challenging and difficult because of the instability of the radical intermediates under the electrolysis conditions, especially using a user-friendly undivided cell. Herein, we report a novel electrosynthesis of pyridine-fused N-heteroaromatics through dehydrogenative cascade cyclization and alkoxylation under oxidant-free conditions. This electrochemical synthesis methodology features green and mild reaction conditions, good functional group tolerance, and the use of readily available substrates. Moreover, attributed to the use of flow electrolysis cells, the steady production and large-scale preparation can be conveniently achieved using only small amounts of electrolytes.