Rhodium(III)-Catalyzed C–H Bond Activation and [3+3] Spirocyclization of Benzoxazines with CF₃‑Imidoyl Sulfoxonium Ylides toward Trifluoromethyl-Substituted Spiroheterocyclic Compounds

Rh(III)-catalyzed C–H bond activation and spirocyclization of benzoxazines with CF3-imidoyl sulfoxonium ylides (TFISYs) have been achieved, providing a direct and facile avenue to structurally diverse trifluoromethyl-substituted spiroheterocycles. The transformation involves a cascade C–H activation, tautomerization, and intramolecular nucleophilic addition pathway. A broad spectrum of spiroheterocycle molecules containing biologically important benzoxazine and isoquinoline skeletons are synthesized in up to 98% yields.