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Updated: May 30, 2025

Light-driven Enzymatic Decarboxylation
Published on: May 22, 2016
Visible Light-Mediated Decarboxylative Giese Addition Utilizing Thioxanthone or Thioxanthone-TfOH Complex as the
Charikleia S Batsika1, Naya A Stini1, Christoforos G Kokotos1
1Laboratory of Organic Chemistry, Department of Chemistry, National and Kapodistrian Un, iversity of Athens, Panepistimiopolis, Athens, 15771, Greece.
This study introduces a green, metal-free photochemical method for organic synthesis. It utilizes carboxylic acids and thioxanthone photocatalyst for efficient 1,4-radical conjugate additions under LED light.
Area of Science:
- Organic Chemistry
- Photochemistry
- Green Chemistry
Background:
- Synthetic photochemistry offers a sustainable alternative for novel reactivity in organic synthesis.
- Carboxylic acids are versatile radical precursors for light-mediated reactions, enabling access to unique products.
Purpose of the Study:
- To develop a green, cost-effective, and metal-free photochemical protocol for the Giese reaction.
- To explore the use of thioxanthone as a photocatalyst for decarboxylative radical conjugate addition.
Main Methods:
- Photochemical decarboxylative 1,4-radical conjugate addition (Giese reaction).
- Utilized thioxanthone or a thioxanthone-triflic acid complex as a photocatalyst.
- Employed LED irradiation at 427 nm with various carboxylic acids, amino acids, and Michael acceptors.
Main Results:
- Achieved efficient 1,4-radical conjugate addition via a decarboxylative pathway.
- Demonstrated the utility of thioxanthone-based photocatalysis in metal-free conditions.
- Obtained desired products in good to high yields across a range of substrates.
Conclusions:
- The developed protocol is a green and sustainable method for organic synthesis.
- Thioxanthone is an effective metal-free photocatalyst for Giese reactions.
- This photochemical approach expands synthetic possibilities for complex molecule construction.
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