Photoinduced Vinylogous Dearomatization

Area of Science:

• Organic Chemistry
• Photochemistry
• Medicinal Chemistry

Background:

• Vinylogous dearomatization is a key transformation for constructing complex organic molecules.
• Benzothiophenes and chromones are prevalent scaffolds in pharmaceutically active compounds.
• Developing efficient synthetic routes to access these structures is of significant interest.

Purpose of the Study:

• To report the first example of vinylogous dearomatization involving benzothiophenes.
• To develop a photoinduced synthetic strategy for accessing valuable pharmaceutical building blocks.
• To explore the reaction scope and mechanism of this novel transformation.

Main Methods:

• Utilized a photoinduced platform for the reaction.
• Employed functionalized benzothiophenes and 3-methylenechroman-4-ones as starting materials.
• Investigated reaction intermediates and mechanistic pathways, including hydrogen-atom transfer and radical coupling.

Main Results:

• Achieved efficient synthesis of diverse products containing both chromone and 2,3-dihydrobenzo[b]thiophene moieties.
• Demonstrated the utility of the developed method for constructing complex molecular architectures.
• Elucidated the reaction mechanism involving key steps like dearomatization and radical cross-coupling.

Conclusions:

• Successfully established the first vinylogous dearomatization of benzothiophenes.
• The photoinduced method provides a facile route to pharmaceutically relevant chromones and dihydrobenzothiophenes.
• This work expands the synthetic toolbox for accessing valuable heterocyclic compounds.