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Enantioselective Allylation Using Allene, a Petroleum Cracking Byproduct
Richard Y Liu1, Yujing Zhou1, Yang Yang1
1Department of Chemistry , Massachusetts Institute of Technology , 77 Massachusetts Avenue , Cambridge , Massachusetts 02139 , United States.
Journal of the American Chemical Society
|January 29, 2019
Summary
Allene gas and hydrosilanes offer a greener alternative to traditional allylmetal reagents for ketone allylation. This copper-catalyzed reaction is efficient, selective, and uses readily available materials.
Area of Science:
- Organic Chemistry
- Catalysis
- Sustainable Synthesis
Background:
- Allene (C3H4) is a high-volume byproduct of petroleum refining with limited synthetic applications.
- Ketone allylation, the addition of an allyl group (C3H5) to ketones, is a fundamental transformation in organic synthesis.
- Traditional methods often rely on stoichiometric, less environmentally friendly allylmetal reagents.
Purpose of the Study:
- To develop a sustainable and efficient method for ketone allylation using allene gas.
- To replace stoichiometric allylmetal reagents with catalytic systems.
- To explore the use of inexpensive and environmentally benign hydrosilanes as allylating agents.
Main Methods:
- Copper-catalyzed reaction of allene gas with hydrosilanes (e.g., PMHS).
- Utilized commercially available copper salts and ligands.
- Operated under standard laboratory conditions without specialized equipment or pressurization.
Main Results:
- Developed a catalytic system that effectively replaces stoichiometric allylmetal reagents.
- Achieved high chemoselectivity, allowing direct use of industrially relevant C3 hydrocarbon mixtures.
- Demonstrated broad functional group tolerance in the ketone allylation reaction.
Conclusions:
- The developed copper-catalyzed process provides a sustainable and cost-effective route for enantioselective ketone allylation.
- This method offers a greener alternative by utilizing abundant allene gas and benign hydrosilanes.
- The catalyst system's robustness and selectivity enable practical applications in organic synthesis.
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