Synthetic Applications of Nickel‐Catalyzed Cross‐Coupling and Cyclisation Reactions

Abstract

Since the first studies about fifty years ago, the direct formation of C−C bonds, catalyzed by nickel complexes, has appeared as an important research topic, and has re‐emerged recently as a renewal of nickel chemistry. This account provides a summary of the use of nickel complexes in catalysis, and highlights the evolution of our own research.

Nickel‐Catalyzed Intramolecular Hydrosilylation of Alkynes: Embracing Conventional and Electrochemical Routes

“…Electrochemistry presents itself as a mild, non-polluting alternative for generating low-valent nickel. [25] We hypothesized that electro-conversion of arylsilanes 2 would offer straightforward access to the corresponding cyclized products 3. To this end, we chose to conduct the optimization reaction on substrate 2 a.…”

“…This would allow us to perform these intramolecular hydrosilylation reactions in a gentle manner. Electrochemistry presents itself as a mild, non‐polluting alternative for generating low‐valent nickel [25] . We hypothesized that electro‐conversion of arylsilanes 2 would offer straightforward access to the corresponding cyclized products 3 .…”

Advances in Cross-Coupling Reactions Catalyzed by Aromatic Pincer Complexes Based on Earth-Abundant 3d Metals (Mn, Fe, Co, Ni, Cu)

“…This reaction catalyzed using Pd or Ni deriva use of an organometallic reagent (a Grignard reagent) and aryl or al duce a C-C bond (Scheme 1). In the last few years, the efforts to apply nickel or palladium com in cross-coupling reactions with non-activated organic halides have especially on those with β-hydrogen atoms [47][48][49][50]. According to Hu troubles with alkyl halides in cross-coupling reactions are: (1) alkyl h ceptible to oxidative addition with a metal catalyst; (2) alkyl interm elimination, and as a result, cross-coupling is inefficient; and (3) alkyl h suffer diverse side reactions such as base-promoted halide elimination ation [51].…”

“…In the last few years, the efforts to apply nickel or palladium complexes as catalysts in cross-coupling reactions with non-activated organic halides have been challenging, especially on those with β-hydrogen atoms [47][48][49][50]. According to Hu [49], the most cited troubles with alkyl halides in cross-coupling reactions are: (1) alkyl halides are less susceptible to oxidative addition with a metal catalyst; (2) alkyl intermediates suffer β-H elimination, and as a result, cross-coupling is inefficient; and (3) alkyl halides are prone to suffer diverse side reactions such as base-promoted halide elimination or hydrohalogenation [51].…”