文摘
Intramolecular C(sp3)鈥揌 bond activation reactions mediated by low-valent cobalt, both Co(I) and Co(0), have been observed in the reactions of the three-coordinate cobalt complex [Co(IMes)2Cl] (IMes = 1,3-dimesitylimidazol-2-ylidene) with alkylation reagents and sodium amalgam. The reactions with alkylation reagents gave [Co(IMes)(IMes鈥?(N2)], featuring a metalated IMes鈥?anion, whereas the one-electron-reduction reaction afforded [Co(IMes鈥?2]. The Co(II) complex can react with CO, isocyanide, and a diazo compound to furnish interesting cobalt complexes bearing functionalized N-heterocyclic carbene ligands. The establishment of these conversions demonstrates the capability of low-valent cobalt with coordination unsaturation to mediate C(sp3)鈥揌 bond activation and functionalization.