Palladium-Catalyzed Domino Allenamide Carbopalladation/Direct C–H Allylation of Heteroarenes: Synthesis of Primprinine and Papaverine Analogues

Palladium-catalyzed intramolecular carbopalladation onto allenamides completed by direct C–H allylation of heterocycles is studied. The domino construction/heteroarylation of isoquinolone process is first achieved. A general three-step one-pot strategy, involving in situ generation of allenamide, π-allyl-Pd complex generation, and interception with heteroarenes, has been subsequently set up. This methodology has been extended to the construction/heteroarylation of indoles, dihydroquinolines, isoquinolin(on)es, and medium-sized nitrogen heterocycles, which are known to be key challenging structural motifs with pharmaceutical significance.