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Updated: May 27, 2026

Facile Preparation of (2Z,4E)-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate
Published on: June 21, 2017
Enantioselective decarboxylative alkylation reactions: catalyst development, substrate scope, and mechanistic studies
Douglas C Behenna1, Justin T Mohr, Nathaniel H Sherden
1The Warren and Katharine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E. California Blvd., MC 101-20, Pasadena, CA 91125, USA.
This study introduces a new method for creating α-quaternary ketones using enantioselective alkylations. Palladium complexes with phosphinooxazoline (PHOX) ligands enable high yields and enantioselectivity with various enolate precursors.
Area of Science:
- Organic Chemistry
- Catalysis
- Asymmetric Synthesis
Background:
- α-Quaternary ketones are important motifs in organic synthesis.
- Developing efficient enantioselective methods for their synthesis remains a challenge.
Purpose of the Study:
- To develop novel enantioselective alkylation methods for accessing α-quaternary ketones.
- To explore the use of palladium complexes with phosphinooxazoline (PHOX) ligands.
Main Methods:
- Enantioselective alkylation of allyl and propargyl electrophiles.
- Utilized unstabilized prochiral enolate nucleophiles.
- Employed palladium complexes with various phosphinooxazoline (PHOX) ligands.
Main Results:
- Achieved excellent yields and high enantiomeric excesses for α-quaternary ketones.
- Demonstrated efficiency with three enolate precursor classes: enol carbonates, enol silanes, and racemic β-ketoesters.
- Identified an unusual inner-sphere mechanism involving direct binding of the enolate to palladium.
Conclusions:
- The developed method provides a versatile and efficient route to α-quaternary ketones.
- The phosphinooxazoline (PHOX) ligand-based palladium catalysis is highly effective.
- The findings offer insights into the reaction mechanism and potential applications in synthesis.
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