Bioinspired Fe ₃ O ₄ @SiO ₂ / _L -Tryptophan/rGO Hybrid as a Photocatalyst for the Tandem Photooxidation–Condensation Synthesis of N-Heterocycles

Developing catalysts that simultaneously drive oxidative and reductive steps under ambient conditions remains a formidable challenge in sustainable organic synthesis. Here, we unveil a four-functional hybrid photocatalyst, Fe3O4@SiO2/L-tryptophan/rGO, that achieves this feat without requiring external oxidants or metal cocatalysts. Under visible light, this photocatalyst enables the one-pot transformation of benzyl alcohols and nitroarenes into valuable nitrogen-containing heterocycles, including benzoxazole derivatives and quinoxalines, via tandem photooxidation–condensation. The system exhibits remarkable selectivity, high functional-group tolerance, and full recyclability, offering rare catalytic duality in both oxidative and reductive regimes. More strikingly, this photocatalyst is constructed from biologically derived and earth-abundant components, advancing a truly green platform for heterocycle synthesis. This work establishes a blueprint for photocatalysts that simplify the reaction design and redefine what is chemically possible under mild, sustainable conditions.