Recent advances in organic synthesis via synergistic nickel/copper catalysis

Synergistic Ni/Cu catalytic systems have emerged as a powerful strategy in the catalytic C-C and C-X bond -forming reactions. In this review, recent significant advances in the formation of C-C and C-X bonds achieved by using synergistic Ni/Cu catalytic systems are summarized, mainly involving Sonogashira-type reactions, asymmetric allylic/propargylic alkylations, hydrofunctionalizations of alkenes/alkynes, silylations, borylations, Suzuki-type reaction, C-H bond functionalization, Nazarov cyclization, and diarylation of unreactive alkenes. Additionally, the mechanisms, synthetic applications, and limitations of these reactions have been discussed. Compared to other well-established bimetallic catalyst systems, such as Pd/Cu catalysis, Ni/Cu catalysis system is still in the rapid development stage. It has unique advantage such as low cost, low possibility of the occurrence of beta-H elimination in the presence of alkyl electrophiles, facile oxidative addition and multiple oxidation states, etc. Therefore, it is expected that the Ni/Cu catalyst system will play an increasingly great role in the development of organic synthesis, medicinal chemistry, and materials science in the near future.