Pauson-Khand Reaction Mechanism, and Applications

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Pauson-Khand Reaction, examples, mechanisms, and applications in organic chemistry have been discussed here:

Pauson-Khand Reaction

The ring formation reaction involves [2+2+1] cycloaddition between an alkyne, an alkene, and carbon monoxide to form α, β-cyclopentenone known as Pauson-Khand reaction. In other words, it is one step-synthesis α, β-unsaturated cyclopentenone from the [2+2+1] cycloaddition of alkyne, alkene, and carbon monoxide, via an intermediate of alkynedicobalt hexacarbonyl complex. Pauson-Khand reaction is also known as Pauson-Khand cyclization, Pauson-Khand cycloaddition, or Pauson-Khand annulation.

Several Pauson-Khand reactions are intended as intramolecular reactions in order to attain stereochemical control. In the case of intermolecular Pauson-Khand reaction, due to steric hindrance, an alkene is positioned next to the less bulky acetylenic substituent during coordination, and a subsequent C-C bond forms between an alkene carbon and the closer acetylenic carbon, leading to the formation of the larger group on alkyne being found at the α-position of the resulting cyclopentenone.

The Pauson-Khand reaction has also been performed under a variety of conditions, including the use of chiral ligands, aldehydes as a carbon monoxide source, solid-supported cobalt catalysts to improve purification, colloidal cobalt nanoparticles, and so on.

The pauson-Khand reaction can be represented as:

Pauson-khand reaction. pauson-khand reaction examples, pauson-khand reaction mechanism
Image Source: https://en.wikipedia.org/wiki/File:Pauson_Khand_reaction_original.svg#filelinks

Pauson-Khand Reaction Mechanism

The mechanism of the Pauson-Khand reaction can be carried out in the following way:

Pauson-khand reaction mechanism, pauson-khand reaction, pauson-khand examples
Image Source: https://doi.org/10.1515/9783110608373

Applications of Pauson-Khand reaction

The Pauson–Khand reaction is commonly used to prepare cyclopentenones and their derivatives. This reaction also aids in the overall synthesis of a number of topologically complicated natural products with a variety of structural characteristics.

Pauson-Khand Reaction Video

FAQs/MCQs

What is Pauson-Khand reaction?

Pauson-Khand reaction is [2+2+1] cycloaddition between an alkyne, an alkene, and carbon monoxide to form α, β-cyclopentenone.

Uses of Pauson-Khand reaction

Pauson-Khand reaction is used to prepare cyclopentenone.

References

  • March, J., Advanced Organic Chemistry, Wiley Eastern Limited, 1986.
  • Skyes, P., A Guide Book to Mechanism in Organic Chemistry, Second edition, Orient Longman Ltd., 1988.
  • Ahmar, M.; Knoke, M.; de Meijere, A. and Cazes, B., Synthesis, 2007, 442.
  • Perez-Serrano, L.; Blanco-Urgoiti, J.; Casarrubios, L.; Dom ´ ´ınguez, G. and Perez-Castells, J., ´J. Org. Chem., 2000, 65, 3513
  • Jeong, N.; Hwang, S. H.; Lee, Y. W. and Lim, J. S., J. Am. Chem. Soc., 1997, 119, 10549.

pauson-khand reaction, Pauson-Khand Reaction Mechanism, and Applications

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