Electrochemically driven cross-electrophile coupling of alkyl halides
Abstract
Recent research in medicinal chemistry has suggested that there is a correlation between an increase in the fraction of sp³ carbons—those bonded to four other atoms—in drug candidates and their improved success rate in clinical trials. As such, the development of robust and selective methods for the construction of carbon(sp³)–carbon(sp³) bonds remains a critical problem in modern organic chemistry. Owing to the broad availability of alkyl halides, their direct cross-coupling—commonly known as cross-electrophile coupling—provides a promising route towards this objective. Such transformations circumvent the preparation of carbon nucleophiles used in traditional cross-coupling reactions, as well as stability and functional-group-tolerance issues that are usually associated with these reagents. However, achieving high selectivity in carbon(sp³)–carbon(sp³) cross-electrophile coupling remains a largely unmet challenge. Here we use electrochemistry to achieve the differential activation of alkyl halides by exploiting their disparate electronic and steric properties. Specifically, the selective cathodic reduction of a more substituted alkyl halide gives rise to a carbanion, which undergoes preferential coupling with a less substituted alkyl halide via bimolecular nucleophilic substitution to forge a new carbon–carbon bond. This protocol enables efficient cross-electrophile coupling of a variety of functionalized and unactivated alkyl electrophiles in the absence of a transition metal catalyst, and shows improved chemoselectivity compared with existing methods.
Additional Information
© The Author(s), under exclusive licence to Springer Nature Limited 2022. Received 10 October 2021. Accepted 10 February 2022. Published 21 February 2022. Financial support was provided by NIGMS (R01GM134088; to S.L.), NSF Center for Synthetic Organic Electrochemistry (CHE-2002158; to K.A.S.), and Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA. S.L. is grateful to the Research Corporation for Science Advancement for a Cottrell Scholar Award. This study made use of the NMR facility supported by the NSF (CHE-1531632). XPS data were collected at the Molecular Materials Research Center in the Beckman Institute of the California Institute of Technology. We thank C. Yang for providing propargylic chloride substrates. Data availability: All data supporting the findings of this work are available within the paper and its Supplementary Information. Contributions: S.L. and K.A.S. supervised the project. N.S. and D.L. provided guidance on the project. Wen Zhang and S.L. conceived the work. Wen Zhang, L.L., N.S., D.L. and S.L. designed the experiments. Wen Zhang. and L.L. conducted the synthetic experiments and mechanism studies. Wendy Zhang, S.D.W. and K.A.S. conducted the analysis of electrode passivation. Y.W., J.M. and J.R. conducted the density functional theory calculations. Wen Zhang, L.L., Wendy Zhang, K.A.S. and S.L. wrote the manuscript. N.S., D.L. and S.D.W. edited the manuscript. The authors declare no competing interests. Peer review information: Nature thanks the anonymous reviewers for their contribution to the peer review of this work. Peer reviewer reports are available.Attached Files
Accepted Version - nihms-1793323.pdf
Submitted - electrochemically-driven-cross-electrophile-coupling-of-alkyl-halides.pdf
Supplemental Material - 41586_2022_4540_MOESM1_ESM.pdf
Supplemental Material - 41586_2022_4540_MOESM2_ESM.pdf
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Additional details
- PMCID
- PMC9016776
- Eprint ID
- 112372
- Resolver ID
- CaltechAUTHORS:20211213-518504000
- R01GM134088
- NIH
- CHE-2002158
- NSF
- Merck Sharp and Dohme
- Cottrell Scholar of Research Corporation
- CHE-1531632
- NSF
- Created
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2021-12-13Created from EPrint's datestamp field
- Updated
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2023-07-06Created from EPrint's last_modified field