From α,β-Unsaturated Amide to Enamide: Intramolecular Alkene Translocation via Iridium-Catalyzed Transfer Hydrogenation

Site-selective alkene translocation between two separate segments of a molecule has been a rare and mechanistically intriguing transformation. Herein we report the direct conversion of electrophilic α,β-unsaturated amides to nucleophilic enamides via an Ir-catalyzed alkene translocation across an amide linkage. The reaction is redox-neutral, atom-economical and strong base-free, thus showing broad functional group tolerance. Mechanistic studies reveal that the reaction proceeds through an irreversible intramolecular hydrogen transfer pathway. Preliminary success on enantioselective intramolecular transfer hydrogenation of α,β-unsaturated amides has also been achieved.