Posts Tagged ‘activation free energy barriers’

Yes, no, yes. Computational mechanistic exploration of (nickel-catalysed) cyclopropanation using tetramethylammonium triflate.

Thursday, October 1st, 2015

A fascinating re-examination has appeared[1] of a reaction first published[2] in 1960 by Wittig and then[3] repudiated by him in 1964 since it could not be replicated by a later student. According to the new work, the secret to a successful replication seems to be the presence of traces of a nickel catalyst (originally coming from e.g. a nickel spatula?). In this recent article[1] a mechanism for the catalytic cycle is proposed. Here I thought I might explore this mechanism using calculations to see if any further insights might emerge.



  1. S.A. Künzi, J.M. Sarria Toro, T. den Hartog, and P. Chen, "Nickel-Catalyzed Cyclopropanation with NMe4 OTf and n BuLi", Angewandte Chemie International Edition, vol. 54, pp. 10670-10674, 2015.
  2. V. Franzen, and G. Wittig, "Trimethylammonium-methylid als Methylen-Donator", Angewandte Chemie, vol. 72, pp. 417-417, 1960.
  3. G. Wittig, and D. Krauss, "Cyclopropanierungen bei Einwirkung vonN-Yliden auf Olefine", Justus Liebigs Annalen der Chemie, vol. 679, pp. 34-41, 1964.