Green One-Pot Strategy for the Direct Synthesis of Benzil

A practical and green methodology has been developed for the direct synthesis of arylated 1,2-diketones from aldehydes utilizing 4 mol% of N-heterocyclic carbenes (NHC) organocatalysts and activated carbon. The design of this method is a one-pot, two-step sequence: NHC-catalyzed benzoin condensation followed by aerobic oxidation in the presence of activated carbon (AC) and molecular O_2, offering good to high yields, tolerating various functional groups. This method demonstrates a sustainable and eco-friendly protocol for efficiently synthesizing benzil scaffolds from a wide range of aldehydes directly through one-pot conversions. Catalyst loading, solvent screening, and mechanistic experiments were also performed to understand the roles of NHC catalysts and activated charcoal.