A general arene C-H functionalization strategy via electron donor-acceptor complex photoactivation
Abhishek Dewanji1, Leendert van Dalsen1, James A Rossi-Ashton1
1Department of Chemistry, The University of Manchester, Manchester, UK.
Nature Chemistry
|December 5, 2022
Summary
This study introduces triarylsulfonium salts for generating aryl radicals via photoactivation, enabling general and site-selective C-H functionalization of arenes without metal catalysts.
Area of Science:
- Organic Chemistry
- Photochemistry
- Synthetic Methodology
Background:
- Photoactivation of electron donor-acceptor complexes is a sustainable strategy for radical generation.
- Aryl radical formation is limited by precursor electronic properties and requires electron-deficient aryl halides.
- A general synthetic platform for aryl radical formation is lacking.
Purpose of the Study:
- To develop a general and site-selective method for aryl radical formation using photoactive electron donor-acceptor complexes.
- To introduce triarylsulfonium salts as versatile acceptors in this process.
- To establish metal-free protocols for arene functionalization.
Main Methods:
- Utilized triarylsulfonium salts as acceptors with novel amine donors in photoactive electron donor-acceptor complexes.
- Employed regioselective C-H sulfenylation to install the sulfonium salt label onto aromatic compounds.
- Developed metal-free protocols for arene alkylation and cyanation.
Main Results:
- Demonstrated that the sulfonium salt acceptor makes the electronic properties of the aryl radical precursor inconsequential.
- Achieved general and site-selective aromatic C-H functionalization.
- Successfully applied the method in the synthesis and late-stage modification of pharmaceuticals and agrochemicals.
Conclusions:
- Triarylsulfonium salts serve as effective acceptors for aryl radical generation via photoactivation.
- The developed C-H functionalization approach is general, site-selective, and metal-free.
- This methodology offers a versatile platform for synthesizing and modifying complex organic molecules, including pharmaceuticals and agrochemicals.
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