Nickel/Photoredox Dual Catalytic Cross-Coupling of Alkyl and Amidyl Radicals to Construct C(sp3)–N Bonds
Shaofang Zhou1, Kang Lv1, Rui Fu1, Changlei Zhu1,and Xiaoguang Bao1,*
1 Soochow Univ, Coll Chem Chem Engn & Mat Sci, Innovat Ctr Chem Sci, Suzhou 215123, Jiangsu, Peoples R China
ACS Catal. 2021, 11, 9, 5026–5034
The construction of C(sp(3))-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 (Ru-II/*Ru-II/Ru-III/Ru-II) combined with a possible Ni-I/Ni-II/Ni-III/Ni-I catalytic cycle is proposed to account for the nickel/photoredox dual-catalyzed C(sp(3))-N bond formation based on synergistic experimental and computational studies.
