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Updated: Dec 22, 2025

Isolating Free Carbenes, their Mixed Dimers and Organic Radicals
Published on: April 19, 2019
Hydroarylation of Arenes via Reductive Radical-Polar Crossover
Autumn R Flynn1, Kelly A McDaniel1, Meredith E Hughes1
1Department of Chemistry and Winship Cancer Institute, Emory University, Atlanta, Georgia 30322, United States.
Abstract:
A photocatalytic system for the dearomative hydroarylation of benzene derivatives has been developed. Using a combination of an organic photoredox catalyst and an amine reductant, this process operates through a reductive radical-polar crossover mechanism where aryl halide reduction triggers a regioselective radical cyclization event, followed by anion formation and quenching to produce a range of complex spirocyclic cyclohexadienes. This light-driven protocol functions at room temperature in a green solvent system (aq. MeCN) without the need for precious metal-based catalysts or reagents or the generation of stoichiometric metal byproducts.
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