Gold‐Catalyzed [4+2] Annulation/Cyclization Cascades of Benzisoxazoles with Propiolate Derivatives to Access Highly Oxygenated Tetrahydroquinolines

This work describes gold‐catalyzed annulations of electron‐deficient alkynes with benzisoxazoles to yield quinoline oxides chemoselectively. Chemical functionalizations of these resulting azacyclic compounds afforded various oxygenated tetrahydroquinolines which are present as the cores of many bioactive molecules. With the same reactants, a new relay catalysis using gold and zinc(II) catalysts affords highly oxygenated tetrahydroquinoline derivatives stereoselectively. Tag team: This work describes gold‐catalyzed [4+2] annulation/cyclization cascades of electron‐deficient alkynes with benzisoxazoles to yield quinoline oxides chemoselectively. With the same reactants, a new relay catalysis using gold and zinc(II) catalysts afford highly oxygenated tetrahydroquinoline derivatives stereoselectively. Tf=trifluoromethanesulfonyl.