Semiheterogeneous Intrinsic CoS 2 -Photoredox/Cp 2 Fe Dual-Catalyzed Synthesis of Selenylated Phenanthrene

Herein, we report a practical semiheterogeneous strategy for the photosynthesis of diverse selanyl phenanthrenes, employing CoS2 as a heterogeneous photocatalyst in combination with ferrocene (Cp2Fe) as a homogeneous redox catalyst. This synergistic system combines photogenerated electron-mediated reduction of selenyl cations into diselenide with photogenerated hole oxidation of Cp2Fe to its oxidized form, which not only oxidizes diselenide into selenyl radicals but also mediates oxidative dehydroaromatization, leading to high-yielding transformations with broad functional group compatibility. Notably, this method eliminates the need for stoichiometric oxidants or reductants and avoids sacrificial electron donors or acceptors.