Stoichiometric and Catalytic Lithium Nickelate-Mediated C-F Bond Alkynylation of Fluoroarenes.

Low-valent nickelates have recently been shown to be key intermediates that facilitate challenging cross-coupling reactions under mild conditions. Expanding the synthetic potential of these heterobimetallic complexes, herein we report the success of trilithium nickelate Li(TMEDA)Ni(C≡C-Ph) in promoting stoichiometric C-F activation of assorted aryl fluorides furnishing novel mixed Li/Ni(0) or Li/Ni(II) species depending on the substrate and conditions employed. These stoichiometric successes can be upgraded to catalytic regimes to enable the atom-efficient alkynylation of aryl fluorides and polyfluoroarenes with lithium acetylides and precatalyst Ni(COD), which operates without the intervention of external ligands, Cu cocatalysts, or additives.