Sulfonamide-Controlled Pd(II)-Catalyzed [5+2] Rollover Annulation to Access (Hetero)pyrido-Fused 1-Benzazepines

Abstract

A novel palladium-catalyzed rollover annulation is developed for the synthesis of pyrido-fused 1-benzazepines from N-sulfonyl-N-phenyl-2-aminopyridines and alkynes. Operating via a formal [5+2] cycloaddition with sequential aryl and heteroaryl C–H activations, the reaction relies on a key sulfonamide directing group to control periselectivity over competing [3+2] indole formation. The resulting benzazepines provide direct access to complex seven-membered N-heterocycles and serve as versatile intermediates for divergent skeletal editing into ring-expanded sultams and ring-contracted pyrroles.