# Revisiting Reaction Mechanism of Regioselective Disulfide‐Catalyzed Photocatalytic Aerobic Oxidative Cleavage of 1‐Arylbutadienes: A Computational Study

## TL;DR

This study uses computational methods to determine the reaction mechanism of a photocatalytic oxidation process involving 1-arylbutadienes and disulfides.

## Contribution

The study proposes a new reaction mechanism involving peroxyl radical reduction or dimerization instead of dioxetane ring formation.

## Key findings

- The reaction proceeds via intramolecular reduction or dimerization of peroxyl radical.
- The dioxetane ring formation mechanism is not supported due to ring strain.
- S—S bond homolysis in diaryl disulfides cannot be achieved by visible light irradiation under reaction conditions.

## Abstract

A computational study of the regioselective aerobic oxidative cleavage of 1‐arylbutadienes is carried out employing density functional theory and high‐level coupled‐cluster methods, such as coupled‐cluster singles and doubles with perturbative triples [CCSD(T)]. The results demonstrate that the reaction proceeds either via the intramolecular reduction or dimerization of peroxyl radical. These findings are in contrast to a previously proposed mechanism that progresses via formation of the dioxetane ring. The computations further indicate that the homolysis of S—S bond of diaryl disulfide derivatives cannot be achieved by irradiation with direct visible light under the reaction conditions due to the high bond dissociation energy.

This study demonstrates that the regioselective aryldisulfide‐catalyzed photocatalytic aerobic oxidative cleavage of 1‐arylbutadienes progresses through reduction or dimerization of peroxyl radical contrary to the formation of dioxetane suffering from the ring strain.© 2025 WILEY‐VCH GmbH