Ligand-free Nickel-catalyzed carboxylate O-arylation: Mechanistic in-sight into NiI/NiIII cycles

01 April 2022, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


Nickel-catalyzed cross-coupling reactions have become a powerful methodology to construct C–heteroatom bonds. How-ever, many protocols suffer from competitive off-cycle reaction pathways and require non-equimolar amounts of cou-pling partners to suppress them. Here, we report on mechanistic examination of carboxylate O-arylation under thermal conditions, in both the presence and absence of an exogeneous bipyridine-ligand. Furthermore, spectroscopic studies of the novel ligand-free carboxylate O-arylation reaction unveiled the resting state of the nickel catalyst, the crucial role of the alkylamine base and the formation of a catalytically relevant NiI–NiII dimer upon reduction. This study provides in-sights into the competition between productive catalysis and deleterious pathways (comproportionation and pro-todehalogenation) that exist for all elementary steps in the commonly proposed self-sustained NiI/NiIII catalytic cycle. Thereby we show that for productive nickel-catalyzed carboxylate O-arylation a choice must be made between either mild conditions or equimolar ratios of substrates.


C-heteroatom bond formatiom

Supplementary materials

Supplementary Materials for Ligand-free Nickel-catalyzed carboxylate O-arylation: Mechanistic insight into Ni(I)/Ni(III) cycles
Methods and materials, spectroscopic details, additional experiments performed,


Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.