Rhodium(III)-Catalyzed Intramolecular Annulation through CH Activation: Total Synthesis of (±)-Antofine, (±)-Septicine, (±)-Tylophorine, and Rosettacin

Annulation: The efficient synthesis of 3‐hydroxyalkyl isoquinolones and 6‐hydroxyalkyl 2‐pyridones is enabled through the intramolecular annulation of alkyne‐tethered hydroxamic esters (see scheme, Cp*=pentamethylcyclopentadienyl). The reaction features high regioselectivity, broad substrate scope, and excellent functional‐group tolerance, proceeds under mild reaction conditions with low catalyst loading, and obviates the need for an external oxidant.