Fig. 6: Mechanism investigations.

a In the control experiments, metal catalysis, ligand, and base are essential for this catalytic cycle. b Radical inhibition reactions using TEMPO. c Radical trapping reactions using 1,1-Diphenylethylene. d Standard reaction condition using Ni(II) complex. dtbpy = 4,4′-di-tert-butyl-2,2′-dipyridyl. e To explore the role of PCy3. a Yields were determined by gas chromatography (GC) using n-dodecane as the internal standard. TEMPO = 2,2,6,6-tetramethylpiperidinyloxy, PCy3 = tricyclohexyl phosphine, DMA = N, N-dimethylacetamide, DME = 1,2-dimethoxyethane.