(NHC)NiCp2 complexes: new air-stable thermally activated precatalysts for olefin hydroheteroarylation

Readily available air-stable (NHC)NiCp₂ complexes (NHC is N-heterocyclic carbene, Cp is cyclopentadienyl anion ligand) can be used as efficient thermally activated precatalysts for hydroheteroarylation of olefins with various heteroarenes. According to preliminary mechanistic studies, precatalyst activation may involve reductive elimination of two Cp ligands to give 1,1’’-bi(cyclopenta-2,4-diene) and (NHC)Ni⁰ active species under elevated temperature.