Dichloromethylation of enones by carbon nitride photocatalysis

Small organic radicals are key in photocatalysis for installing functional groups and modifying molecule properties. Using a heterogeneous potassium poly(heptazine imide) (K-PHI) photocatalyst under visible light, we generate dichloromethyl radicals from chloroform to extend the enone backbone. This method produces γ,γ-dichloroketones from 15 enones (18% to 89% yield). Employing K-PHI in a quasi-homogeneous flow-photoreactor boosts productivity by 19 times compared to batch methods, due to its small particle size (100 nm) and negative zeta-potential (-40 mV). These γ,γ-dichloroketones serve as versatile precursors for synthesizing substituted furans and pyrroles, enhancing organic synthesis capabilities.