Regio- and chemoselective catalytic partial transfer hydrogenation of quinolines by dinuclear aluminum species

Catalytic reduction of quinolines has gained continuous interest in both academia and industry, providing direct and efficient access to tetrahydroquinolines or 1,2-dihydroquinolines. The catalytic preparation of tetrahydroquinolines has been extensively studied by transition metal complexes. By contrast, the related catalytic synthesis of 1,2-dihydroquinolines remains underdeveloped due to the difficulties in achieving precise control over both chemo- and regioselectivity. Here, we demonstrate a catalytic 1,2-reduction of quinolines using a dinuclear aluminum complex, allowing for the highly selective synthesis of a rich array of 1,2-dihydroquinolines through the combination of bimetallic catalysis and metal-ligand cooperation. These investigations showcase the capacity of main group metal catalysts to achieve reactivities distinct from well-studied transition-metal catalysis.