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Visible-Light-Promoted C-S Cross-Coupling via Intermolecular Charge Transfer
Bin Liu1, Chern-Hooi Lim1, Garret M Miyake1
1Department of Chemistry, Colorado State University , Fort Collins, Colorado 80523, United States.
Journal of the American Chemical Society
|September 15, 2017
Summary
This study introduces a novel, metal-free cross-coupling reaction using visible light to form carbon-sulfur bonds from thiols and aryl halides. This method is scalable and useful for synthesizing pharmaceutical compounds.
Area of Science:
- Organic Chemistry
- Catalysis
- Medicinal Chemistry
Background:
- Carbon-sulfur bond formation is crucial for synthesizing pharmaceuticals.
- Traditional methods often rely on transition metals or harsh conditions.
Purpose of the Study:
- To develop a mild, scalable, and metal-free method for C-S bond construction.
- To enable efficient synthesis of aryl thioethers for pharmaceutical applications.
Main Methods:
- Visible-light-promoted cross-coupling reaction.
- Utilized thiols and aryl halides as substrates.
- Investigated reaction mechanism using UV-vis spectroscopy and DFT calculations.
Main Results:
- Successfully formed C-S bonds between a wide range of thiols and aryl halides (>60 examples).
- Demonstrated the protocol's utility in drug synthesis and late-stage API modification.
- Identified intermolecular charge transfer in a thiolate-aryl halide complex as the key reactivity driver.
Conclusions:
- The developed visible-light reaction offers a sustainable and efficient alternative for aryl thioether synthesis.
- This metal-free approach provides a valuable tool for medicinal chemistry and drug discovery.
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