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A Microwave-Assisted Direct Heteroarylation of Ketones Using Transition Metal Catalysis
Published on: February 16, 2020
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Electron Shuttle in N-Heteroaromatic Ni Catalysts for Alkene Isomerization
Maxime Tricoire1, Ding Wang1, Thayalan Rajeshkumar2
1LCM, CNRS, Ecole polytechnique, Institut Polytechnique de Paris, Route de Saclay, 91120 Palaiseau, France.
JACS Au
|August 29, 2022
Summary
This study introduces novel N-heteroaromatic nickel(II) precatalysts for alkene isomerization. A unique reduction method utilizing a lanthanide fragment enabled efficient Ni(I) catalysis with low loading.
Area of Science:
- Organometallic Chemistry
- Catalysis
- Nickel Complexes
Background:
- Alkene isomerization is a crucial transformation in organic synthesis.
- Developing efficient and selective catalysts for alkene isomerization remains a challenge.
- Low-valent nickel species are implicated in various catalytic cycles but are often difficult to generate and stabilize.
Purpose of the Study:
- To develop novel N-heteroaromatic Ni(II) precatalysts for alkene isomerization.
- To investigate the role of a reducing divalent lanthanide fragment in stabilizing low-valent nickel species.
- To explore the mechanism of alkene isomerization mediated by Ni(I) species.
Main Methods:
- Synthesis of Ni(II) precatalysts: (L)NiMe2 (L = bipy, bipym).
- Reduction using borane (HB(Cat)) and coordination with Cp*2Yb.
- Experimental mechanistic studies and computational analysis.
- Testing catalytic activity with various alkenes.
Main Results:
- A heterobimetallic catalyst featuring (bipym)NiMe2 and Cp*2Yb demonstrated efficient alkene isomerization.
- The redox non-innocence of the ligand facilitated an electron shuttle, enabling the formation of active Ni(I) species.
- The catalyst exhibited selectivity for mono-isomerization over chain-walking isomerization.
- Catalytic loading as low as 0.5% was achieved due to catalyst stabilization by the ytterbium fragment.
Conclusions:
- The developed heterobimetallic system provides a robust platform for Ni(I)-catalyzed alkene isomerization.
- Tuning the ligand and lanthanide components offers potential for diverse catalytic applications.
- The study highlights the importance of redox non-innocent ligands and lanthanide cooperation in catalysis.
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