DFT study of the single electron transfer mechanisms in Ni-Catalyzed reductive cross-coupling of aryl bromide and alkyl bromide

摘要

Ni-catalyzed reductive cross-coupling reactions of electrophilic regents provide an important method to form CeC bonds. The present study explored several single electron transfer mechanisms for Nicatalyzed reductive cross-coupling of aryl bromide and secondary alkyl bromide using Density Functional Theory (DFT) calculations. The results showed that two of the proposed mechanisms were feasible. One was a six-step catalytic cycle including oxidative addition, reduction, radical production, radical addition, reductive elimination and catalyst regeneration. The other was a five-step mechanism involving radical production, reduction, oxidative addition, radical addition, and reductive elimination. The ratelimiting step for both mechanisms was the radical addition step with the energy barrier of 10.42 kcal/ mol. All DFT calculations were implemented in the gas phase.