Mechanistic Investigation of the Nickel-Catalyzed Transfer Hydrocyanation of Alkynes
Abstract
The implementation of HCN-free transfer hydrocyanation reactionson laboratory scales has recently been achieved by using HCN donorreagents under nickel- and Lewis acid co-catalysis. More recently,malononitrile-based HCN donor reagents were shown to undergo the C(sp(3))-CN bond activation by the nickel catalyst in theabsence of Lewis acids. However, there is a lack of detailed mechanisticunderstanding of the challenging C(sp(3))-CN bondcleavage step. In this work, in-depth kinetic and computational studiesusing alkynes as substrates were used to elucidate the overall reactionmechanism of this transfer hydrocyanation, with a particular focuson the activation of the C(sp(3))-CN bond to generatethe active H-Ni-CN transfer hydrocyanation catalyst.Comparisons of experimentally and computationally derived C-13 kinetic isotope effect data support a direct oxidative additionmechanism of the nickel catalyst into the C(sp(3))-CNbond facilitated by the coordination of the second nitrile group tothe nickel catalyst. Show more
Permanent link
https://doi.org/10.3929/ethz-b-000629240Publication status
publishedExternal links
Journal / series
ACS CatalysisVolume
Pages / Article No.
Publisher
American Chemical SocietySubject
nickel catalysis; transfer hydrocyanation; shuttle catalysis; aliphatic nitrile activation; mechanistic study; Lewis acid-freeOrganisational unit
09634 - Morandi, Bill / Morandi, Bill
Funding
757608 - Shuttle Catalysis for Reversible Molecular Construction (EC)
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