Photoredox-Mediated Radical Smiles-Truce Rearrangement: From Aryl Migration to Molecular Complexity Generation.

Area of Science:

• Organic Chemistry
• Synthetic Methodology
• Photoredox Catalysis

Background:

• The Smiles-Truce rearrangement is a powerful strategy for arene functionalization via intramolecular C-C bond formation.
• Traditional methods rely on harsh conditions (strong bases), limiting substrate scope and functional group tolerance.
• This restricts its application to simple molecular settings.

Purpose of the Study:

• To redefine the Smiles-Truce rearrangement using visible-light photoredox catalysis.
• To enable mild, catalytic, and broadly applicable arene functionalization and framework reorganization.
• To demonstrate its utility in synthesizing complex molecules and bioactive targets.

Main Methods:

• Development of radical Smiles-Truce rearrangements mediated by visible-light photoredox catalysis.
• Generation of carbon-centered radicals that undergo intramolecular addition to (hetero)arenes.
• Utilizing diverse photoredox activation modes (SET, PCET, deprotonation-oxidation) for modularity.

Main Results:

• Established photoredox-enabled Smiles-Truce rearrangements as a general radical relay for ipso-selective arene functionalization.
• Demonstrated applications in arene dearomatization, framework reorganization, and diastereoselective olefin aminoarylation.
• Achieved enantiospecific variants by transitioning from S(VI) to S(IV) intermediates, introducing stereochemical control.

Conclusions:

• Photoredox catalysis has transformed the Smiles-Truce rearrangement into a programmable platform for molecular reorganization and C-C bond construction.
• This radical approach enables mild conditions, broad substrate scope, and application to complex, functionalized environments.
• Expanded utility in modern synthetic and medicinal chemistry, including the concise synthesis of bioactive compounds.