Abstract

Catalytic asymmetric electrosynthesis combines the unique features of an electrochemical addition or removal of electrons with the catalytic asymmetric synthesis of enantioenriched molecules. However, identifying suitable catalysts that are compatible with electrochemical conditions and provide a high stereocontrol is a formidable challenge. Here we introduce a versatile electricity-driven chiral Lewis acid catalysis for the oxidative cross-coupling of 2-acyl imidazoles with silyl enol ethers. Powered by an electric current, this work provides a sustainable avenue to synthetically useful non-racemic 1,4-dicarbonyls, which include products that bear all-carbon quaternary stereocentres. A chiral-at-metal rhodium catalyst activates a substrate towards anodic oxidation by raising the highest occupied molecular orbital on enolate formation, which enables mild redox conditions, high chemo- and enantioselectivities (up to >99% enantiomeric excess) and a broad substrate scope. This work demonstrates the potential of combining asymmetric Lewis acid catalysis with electrochemistry and we anticipate that it will spur the further development of catalytic asymmetric electrosynthesis.

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Data availability

The X-ray crystallographic coordinates for the structures of Λ-Rh2, 3g, 6n and Rh2-1a reported in this article have been deposited at the Cambridge Crystallographic Data Centre (CCDC) under deposition numbers CCDC 1866726, 1866727, 1868792 and 1866728, respectively. The data can be obtained free of charge from the CCDC via https://www.ccdc.cam.ac.uk/structures/. All other data are available from the authors upon reasonable request.

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Acknowledgements

We are grateful for funding from the Deutsche Forschungsgemeinschaft (grant no. ME 1805/13-1).

Author information

Affiliations

  1. Fachbereich Chemie, Philipps-Universität Marburg, Marburg, Germany

    • Xiaoqiang Huang
    • , Qi Zhang
    • , Jiahui Lin
    • , Klaus Harms
    •  & Eric Meggers

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Contributions

E.M. coordinated the project. E.M. and X.H. conceived the project, designed the experiments and wrote the manuscript. X.H. carried out the majority of the synthetic experiments. Q.Z. and J.L. synthesized and characterized Rh2. K.H. collected the crystallographic data, and solved and refined the X-ray crystal structures.

Competing interests

The authors declare no competing interests.

Corresponding author

Correspondence to Eric Meggers.

Supplementary information

  1. Supplementary Information

    Supplementary Methods, Supplementary Figures 1–41, Supplementary References

  2. Compound Λ-Rh2

    Crystallographic Data for Compound Λ-Rh2

  3. Compound 3g

    Crystallographic Data for Compound 3g

  4. Compound 6n

    Crystallographic Data for Compound 6n

  5. Compound Rh2-1a

    Crystallographic Data for Compound Rh2-1a

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https://doi.org/10.1038/s41929-018-0198-y