Autotandem Chalcogen-Bonding Catalysis: Oxaselenolium-Catalyzed Cascade Povarov–Hydrogen-Transfer Reaction

This study introduces a facile autotandem chalcogen-bonding catalysis. It highlights the innovative application of oxaselenolium as an organocatalyst with dual roles (Lewis acid and radical catalyst) in a one-pot cascade reaction. This reaction integrates an intermolecular Povarov reaction with the transfer hydrogenation of imines, facilitated by in situ-generated tetrahydroquinoline. Notably, this multicomponent reaction enables the efficient synthesis of quinolines and amines with high atom economy, eliminating the need for stoichiometric amounts of external reducing agents and minimizing the necessity for additional hydrogen sources. The protocol demonstrates a broad substrate scope, showcasing its versatility and effectiveness. DFT calculations indicate that oxaselenolium facilitates two distinct mechanistic steps: cycloaddition and hydrogen transfer.