P III P V ═O Redox‐Catalyzed Direct Amide‐to‐Ketimine Transformation via Friedel–Crafts‐type C─C Bond Formation

ABSTRACT A direct and efficient transformation of common secondary amides into aromatic ketimines via C─C bond formation is reported. The process relies on in situ activation of secondary amides through P III /P V ═O redox catalysis to generate reactive imidoyl chloride intermediates. Utilizing hexachloroacetone as a chlorinating agent and only 2 mol% of the phosphorus catalyst, subsequent addition of indole and pyrrole derivatives affords selective C3‐functionalization products. This one‐pot, two‐step protocol provides access to a broad range of C3‐ketimines from diverse secondary amides and heteroarenes, delivering up to 94% yield across 20 newly synthesized compounds. The transformation represents a formal Friedel–Crafts‐type reaction employing secondary amides as electrophilic partners, expanding the synthetic utility of P III /P V ═O redox catalysis and amide activation in heteroarene functionalization.