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Mechanism of the Kinugasa Reaction Revisited.

Stefano SantoroFahmi Himo
Published in: The Journal of organic chemistry (2021)
The mechanism of the Kinugasa reaction, that is, the copper-catalyzed formation of β-lactams from nitrones and terminal alkynes, is re-evaluated by means of density functional theory calculations and in light of recent experimental findings. Different possible mechanistic scenarios are investigated using phenanthroline as a ligand and triethylamine as a base. The calculations confirm that after an initial two-step cycloaddition promoted by two copper ions, the resulting five-membered ring intermediate can undergo a fast and irreversible cycloreversion to generate an imine and a dicopper-ketenyl intermediate. From there, the reaction can proceed through a nucleophilic attack of a ketenyl copper intermediate on the imine and an intramolecular cyclization, rather than through the previously suggested (2 + 2) Staudinger synthesis.
Keyphrases
  • density functional theory
  • molecular dynamics
  • climate change
  • electron transfer
  • oxide nanoparticles
  • mass spectrometry
  • high resolution
  • atomic force microscopy
  • single molecule