2025/08/26 by Alexander Q. Cusumano, Braden C. Chaffin, David A. Cagan +4 · 1 voice
Chemistry · #Catalytic Cross-Coupling Reactions #Catalytic C–H Functionalization Methods #Radical Photochemical Reactions
paper · doi:10.1021/jacs.5c09925
openalex publication_date 2025/08/26 · openalex created_date 2025/08/27 · openalex updated_date 2026/08/01
Ni-catalyzed cross-coupling is a powerful strategy to forge C(sp 3 )–C(sp 3 ) bonds. Typically, to do so requires overcoming a challenging C–C bond-forming reductive elimination, often enabled by the intermediacy of highly oxidized Ni species or outer-sphere processes. While direct C(sp 3 )–C(sp 3 ) reductive elimination from the Ni II base oxidation state is normally thermally inaccessible, light-activation provides an avenue to affect such transformations. Here, we investigate the mechanism of light-induced C(sp 3 )–C(sp 3 ) bond formation from dialkyl bipyridine Ni II complexes through a variety of organometallic, spectroscopic, and computational studies. Wavelength-dependent quantum yields, ligand electronics–reactivity relationships, excited-state lifetimes, computed barriers, and product distributions from crossover studies support a photolysis/radical rebound mechanism. This reactivity paradigm complements existing strategies in the literature to promote reductive elimination from Ni II, such as the use of destabilizing, sterically hindered ligands and reduction of electron density at Ni through the binding of electron-deficient olefins. Hence, we envision that light-induced reductive elimination may enable the development of challenging C(sp 3 )–C(sp 3 ) couplings.