Transition-metal catalyzed directed C—H bond activation and cyclization of unsaturated molecules have been developed as an efficient method to synthesize complex carbon aromatic and heteroaromatic compounds. However, additional stoichiometric oxidants are often required to realize the reoxidation cycle. Electrochemical organic synthesis can use current to replace expensive and toxic oxidants. It is an environment-friendly synthesis method. In recent years, remarkable progress has been made in the combination of electrochemical organic synthesis and C—H activation catalyzed by transition metals (such as Pd, Ni, Co, Ru, Cu, Rh, Ir, etc.). The latest progress of transition-metal catalyzed electrooxidative annulation of unsaturated molecules such as alkynes, olefins, carbon monoxide and isocyanogens via directed C—H activation is reviewed. Finally, the challenges and the future development on this important area are also described.

Key words: C—H bond activation, electrooxidation, cyclization, unsaturated molecule