![Mizoroki-Heck Cross-coupling Reactions Catalyzed by Dichloro{bis[1,1',1''-(phosphinetriyl)tripiperidine]}palladium Under Mild Reaction Conditions](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F51444.jpg&w=3840&q=50)
Radical Pd(III)/Pd(I) reductive elimination in palladium sequences.
Giovanni Maestri1, Max Malacria, Etienne Derat
1Institut de Chimie des Substances Naturelles, ICNS-CNRS UPR2301, Gif/Yvette Cedex 91198, France. giovanni.maestri@cnrs.fr.
Chemical Communications (Cambridge, England)
|October 2, 2013
Summary
Open-shell mechanisms, typically seen in first-row transition metals, may also be relevant in palladium chemistry. Computational studies reveal that palladium(III) intermediates can facilitate C-C bond formation more efficiently than previously thought.
Area of Science:
- Organometallic Chemistry
- Catalysis
- Computational Chemistry
Background:
- Open-shell mechanisms are common in catalysis with first-row transition metals.
- These mechanisms are typically overlooked in palladium-catalyzed reactions.
- Palladium chemistry usually involves closed-shell pathways.
Purpose of the Study:
- To investigate the potential role of open-shell mechanisms in palladium catalysis.
- To explore the relevance of paramagnetic palladium(III) intermediates.
- To computationally assess C-C bond forming reductive elimination pathways.
Main Methods:
- Computational study using density functional theory (DFT).
- Analysis of reaction pathways involving palladium(II), palladium(III), and palladium(IV) species.
- Investigation of radical generation via single-electron transfer (SET).
Main Results:
- Reductive elimination for C-C bond formation has lower energy barriers in neutral, radical palladium(III) intermediates compared to palladium(IV) complexes.
- Paramagnetic palladium(III) species can be formed via addition of aryl radicals to palladium(II).
- These palladium(III) intermediates possess favorable stereoelectronic properties for efficient coupling.
Conclusions:
- Open-shell mechanisms involving palladium(III) intermediates are plausible in catalytic C-C bond formation.
- This finding challenges the traditional view of palladium catalysis.
- Suggests new avenues for designing catalytic systems utilizing radical pathways.
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