A Redox Transmetalation Step in Nickel-Catalyzed C–C Coupling Reactions

Abstract

Ni-catalyzed C−H functionalization reactions are becoming efficient routes to access a variety of functionalized arenes, yet the mechanisms of these catalytic C−C coupling reactions are not well understood. Here, we report the catalytic and stoichiometric arylation reactions of a nickel(II) metallacycle. Treatment of this species with silver(I)−aryl complexes results in facile arylation, consistent with a redox transmetalation step. Additionally, treatment with electrophilic coupling partners generates C−C and C−S bonds. We anticipate that this redox transmetalation step may be relevant to other coupling reactions that employ silver salts as additives.

Nickel binding enables isolation and reactivity of previously inaccessible 7-aza-2,3-indolynes

“…is enhanced in the isolated difunctionalized product compared with that of the monofunctionaled product through both the preferential reaction of one regioisomer of the intermediate σ-aryl complex and chromatography during separation. Because complex 4a is ambiphilic, the reverse addition of the coupling partners of MeI to form complex 6a followed by redox-active transmetalation organometallic reagent MesAg generated the opposite regioisomer of 11a’ exclusively in 34% yield over two steps, which further highlights the potential to expand chemical space from a single starting point ( 51 ).…”

Nickel-Catalyzed Functionalization Reactions Involving C–H Bond Activation via an Amidate-Promoted Strategy and Its Extension to the Activation of C–F, C–O, C–S, and C–CN Bonds

“…Because numerous researchers have now entered this research field in a very short period of time, we gave up on continuing this research. Not only synthetic chemists but also theoretical chemists ,, and organometallic chemists have become interested in the Ni/N,N-bidentate chelation system because the reactions were first proposed to include an unstable high-valence Ni­(IV) and/or Ni­(III) species.…”