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Intermolecular transposed Paternò-Büchi reactions enabled by triplet sensitization
Tahoe A Fiala1, Omar A Solis1, Jesse B Kidd1
1Department of Chemistry, University of Wisconsin-Madison 1101 University Avenue Madison WI 53706 USA tyoon@chem.wisc.edu.
Chemical Science
|November 27, 2025
Summary
Researchers developed a new photocatalytic method for transposed Paternò-Büchi cycloadditions using visible light. This approach utilizes a photosensitizer for selective triplet energy transfer, enabling broader synthetic applications.
Area of Science:
- Organic Photochemistry
- Cycloaddition Reactions
- Photocatalysis
Background:
- The Paternò-Büchi reaction is a classic organic photoreaction forming oxetanes from excited carbonyls and ground-state alkenes.
- The transposed Paternò-Büchi reaction, involving excited alkenes and ground-state carbonyls, is less understood and underdeveloped.
Purpose of the Study:
- To develop a visible light photocatalytic method for transposed Paternò-Büchi cycloadditions.
- To enable a more general and thorough investigation of the synthetic utility of this reaction.
Main Methods:
- Employing a photosensitizer for selective triplet energy transfer to the alkene.
- Utilizing visible light as the energy source for the photocatalytic process.
- Investigating the scope and limitations of the developed reaction conditions.
Main Results:
- Successful implementation of a visible light induced photocatalytic approach for transposed Paternò-Büchi reactions.
- Demonstrated selective triplet energy transfer to the alkene component by the photosensitizer.
- Established general reaction conditions facilitating comprehensive exploration of synthetic opportunities.
Conclusions:
- The developed photocatalytic strategy provides a valuable new tool for accessing oxetanes via transposed Paternò-Büchi cycloadditions.
- This method broadens the synthetic applicability of the transposed Paternò-Büchi reaction under mild, visible light conditions.
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