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Kinetically controlled E-selective catalytic olefin metathesis.
Thach T Nguyen1, Ming Joo Koh1, Xiao Shen1
1Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, MA 02467, USA.
Science (New York, N.Y.)
|April 30, 2016
Summary
Researchers developed new olefin metathesis methods for efficient synthesis of E-isomers. This breakthrough provides direct access to valuable E-alkenyl chlorides and fluorides using molybdenum catalysts.
Area of Science:
- Organic Chemistry
- Catalysis
- Stereoselective Synthesis
Background:
- Olefin metathesis is crucial in chemistry but lacks efficient methods for kinetically favoring E isomers.
- Generating thermodynamically disfavored E isomers remains a significant challenge in synthetic chemistry.
Purpose of the Study:
- To develop novel, kinetically E-selective cross-metathesis reactions.
- To enable the efficient synthesis of thermodynamically disfavored E-alkenyl chlorides and fluorides with high stereoselectivity.
Main Methods:
- Utilized a molybdenum-based catalyst (1.0–5.0 mol%) delivered in stable paraffin pellets.
- Conducted cross-metathesis reactions under ambient temperature, typically completing within 4 hours.
Main Results:
- Achieved high yields and exceptional stereoselectivity for E-alkenyl chlorides and fluorides.
- Demonstrated direct and easy accessibility to isomerically pure E-alkenyl chlorides.
- Successfully synthesized E-alkenyl fluorides from both simple and complex molecules.
Conclusions:
- The developed method overcomes limitations in olefin metathesis, enabling kinetic E-selectivity.
- Provides a versatile route to valuable E-alkenyl halides for further chemical transformations.
- Facilitates the synthesis of biologically relevant compounds containing E-alkenyl moieties.
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