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This review focuses on photocyclization reactions involving alkenes and arenes. Photochemistry opens up synthetic opportunities difficult for thermal methods, using light as a versatile tool to convert stable ground-state molecules into their reactive excited counterparts. This difference can be particularly striking for aromatic molecules, which, according to Baird’s rule, transform from highly stable entities into their antiaromatic “evil twins”. We highlight classical reactions, such as the photocyclization of stilbenes, to show how alkenes and aromatic rings can undergo intramolecular cyclizations to form complex structures. When possible, we explain how antiaromaticity develops in excited states and how this can expand synthetic possibilities. The review also examines how factors such as oxidants, substituents, and reaction conditions influence product selectivity, providing useful insights for improving reaction outcomes and demonstrating how photochemical methods can drive the development of new synthetic strategies.
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Synthesis and Optical Properties of Fluorinated Tetraphenylethylenes**
Abstract Four extensively fluorinated tetraphenylethylenes (TPE) and one extensively fluorinated triphenylethylene have been synthesized using combinations of copper‐catalyzed C−H functionalization reactions and Stille coupling reactions. Surprisingly, in contrast to the parent TPE, these compounds show little to no aggregation‐induced emission (AIE). Instead, photocyclization into fluorinated phenanthrene products occurs. Effects of solvent and oxygen on the yield and selectivity of this photocyclization have been examined.
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- Award ID(s):
- 1904998
- PAR ID:
- 10368968
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- ChemPhotoChem
- Volume:
- 6
- Issue:
- 5
- ISSN:
- 2367-0932
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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