Selective C(sp3)–H Cleavage of Enamides for Synthesis of 2‑Pyridones via Ligand-Enabled Ni–Al Bimetallic Catalysis

Previously reported direct C–H functionalization reactions of enamides mainly occurred at vinylic C­(sp2)–H bonds because of their relatively high reactivity, while less reactive β′-C­(sp3)–H activation has been rarely explored. Herein we report a selective C­(sp3)–H cleavage of N-formyl enamides without backbone modification, providing a series of 2-pyridones in 58–99% yields. A bifunctional phosphine oxide (PO) ligand-bridging Ni–Al bimetallic catalyst played key role in the reaction.