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Chromoselective Photocatalysis Enables Stereocomplementary Biocatalytic Pathways
Luca Schmermund1, Susanne Reischauer2, Sarah Bierbaumer1
1Institute of Chemistry Department of Organic and Bioorganic Chemistry University of Graz, NAWI Graz, BioTechMed Graz Heinrichstrasse 28 8010 Graz Austria.
Angewandte Chemie (Weinheim an Der Bergstrasse, Germany)
|March 20, 2024
Summary
This study demonstrates wavelength-controlled photocatalysis using carbon nitride (CN-OA-m) to tune redox potentials. This enables selective synthesis of (S)- or (R)-phenylethanol enantiomers via photo-chemo-enzymatic cascades.
Area of Science:
- Chemical Engineering
- Photocatalysis
- Enzyme Catalysis
Background:
- Controlling chemical reaction selectivity with external stimuli is established in thermal processes but challenging in visible-light photocatalysis.
- Visible-light photocatalysis offers a sustainable alternative for chemical synthesis, but achieving high enantioselectivity remains a significant hurdle.
Purpose of the Study:
- To demonstrate wavelength-tunable redox potentials of a carbon nitride photocatalyst (CN-OA-m) for controlling chemical reaction selectivity.
- To develop photo-chemo-enzymatic cascades for the enantioselective synthesis of phenylethanol isomers.
Main Methods:
- Tuning the redox potential of CN-OA-m by adjusting irradiation wavelength (green vs. blue light).
- Employing an unspecific peroxygenase from *Agrocybe aegerita* for enantioselective hydroxylation.
- Utilizing an alcohol dehydrogenase from *Rhodococcus ruber* for enantioselective reduction.
Main Results:
- Green light irradiation of CN-OA-m facilitated enantioselective hydroxylation of ethylbenzene to (R)-1-phenylethanol with 99% enantiomeric excess (ee).
- Blue light irradiation of CN-OA-m led to photocatalytic oxidation of ethylbenzene to acetophenone, followed by enantioselective reduction to (S)-1-phenylethanol with 93% ee.
Conclusions:
- Visible-light photocatalysis can be controlled by wavelength to achieve high enantioselectivity in chemical synthesis.
- The developed photo-chemo-enzymatic cascade strategy offers a versatile platform for producing specific enantiomers of valuable chiral compounds.
![Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F60786.jpg&w=3840&q=50)
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