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Imine Metathesis by Silica-Supported Catalysts Using the Methodology of Surface Organometallic Chemistry
Published on: October 18, 2019
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Magnesium hydride alkene insertion and catalytic hydrosilylation
Lucia Garcia1, Chiara Dinoi2, Mary F Mahon1
1Department of Chemistry , University of Bath , Claverton Down , Bath , BA2 7AY , UK .
Chemical Science
|December 10, 2019
Summary
Dimeric magnesium hydride reacts with terminal alkenes to form organometallic compounds, with reaction outcomes influenced by alkene structure. Computational studies reveal the reaction mechanism and its application in catalytic hydrosilylation.
Area of Science:
- Organometallic Chemistry
- Catalysis
- Computational Chemistry
Background:
- Dimeric β-diketiminato magnesium hydride, [(BDI)MgH]₂, is a reactive species.
- Understanding its reactivity with alkenes is crucial for developing new synthetic methods.
Purpose of the Study:
- To investigate the reaction of [(BDI)MgH]₂ with various terminal alkenes and α,ω-dienes.
- To elucidate the reaction mechanism using computational analysis.
- To explore the application of this reactivity in catalytic hydrosilylation.
Main Methods:
- Reactions of [(BDI)MgH]₂ with alkenes and dienes at varying temperatures.
- Characterization of products using X-ray diffraction analysis.
- Density functional theory (DFT) calculations to study reaction pathways and transition states.
Main Results:
- [(BDI)MgH]₂ reacts with terminal alkenes to form magnesium organometallics, with regioselectivity dependent on alkene sterics.
- Reactions with α,ω-dienes yield cyclized products or mixtures of single/double activation products.
- DFT studies indicate Mg-H/C=C insertion is rate-determining in the reaction with 1-hexene.
- The reactivity forms the basis for catalytic hydrosilylation of alkenes, favoring anti-Markovnikov products.
Conclusions:
- The steric and electronic properties of alkenes significantly influence the outcome of reactions with dimeric magnesium hydride.
- Mg-H/C=C insertion is a key step in these reactions, occurring at the intact dimer.
- This magnesium hydride chemistry enables catalytic hydrosilylation, offering a pathway to valuable organosilane products.
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