Nickel/Photoredox Dual Catalytic Cross-Coupling of Alkyl and Amidyl Radicals to Construct C(sp³)–N Bonds

Abstract

The construction of C(sp3)–N bonds via direct radical–radical cross-coupling under benign conditions is a desirable but challenging approach. Herein, the cross-coupling of alkyl and amidyl radicals to build aliphatic C–N bonds in a concise, mild, and oxidant-free manner is implemented by nickel/photoredox dual catalysis. In this protocol, the single electron transfer strategy is successfully employed to generate N- and C-centered radicals from sulfonyl azides/azidoformates and alkyltrifluoroborates, respectively. The photocatalyst-induced triplet–triplet energy-transfer mechanism, however, might not be applicable to this reaction. The oxidative quenching pathway of the excited photocatalyst (RuII/*RuII/RuIII/RuII) combined with a possible NiI/NiII/NiIII/NiI catalytic cycle is proposed to account for the nickel/photoredox dual-catalyzed C(sp3)–N bond formation based on synergistic experimental and computational studies.