Carbamoylation of Aryl and Benzyl Chlorides by Direct C-H Functionalization of Formamide Derivatives via Ni/Photoredox-Catalyzed Cross-Coupling

초록

We report a Ni/photoredox dual catalytic protocol that activates the formyl C-H bond of simple formamides to enable C(sp2)-C(sp2)/C(sp2)-C(sp3) carbamoylation with aryl and benzyl chlorides. This transformation proceeds without the need for prefunctionalized carbamoyl radical precursors, external oxidants, or halogen atom transfer (XAT)/hydrogen atom transfer (HAT) reagents by harnessing in situ-generated Cl radicals for selective HAT followed by the cross-coupling event. This strategy provides a mild and atom-economical platform for accessing structurally diverse amides, including sterically hindered variants that are difficult to access through classical C-N bond-forming methodologies. Stoichiometric studies of independently synthesized Ni complexes reveal a distinct pathway involving a Ni(II)(carbamoyl)Cl complex as the active intermediate, diverging from the previously established C(sp3)-H functionalization chemistry.

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