Aerobic Oxidative N-Heterocyclic Carbene-Catalyzed Formal [3+3] Cyclization for the Synthesis of Tetrasubstituted Benzene Derivatives.

Herein, we present an accessible aerobic N-heterocyclic carbene (NHC)-catalyzed method that efficiently produces tetrasubstituted benzene rings in a single reaction. The method employs atmospheric oxygen (O2) as the terminal oxidant in a reaction that requires two oxidative steps. The aerobic oxidation is achieved by a selection of electron transfer mediators orchestrating a redox cascade, turning a high-energy aerobic oxidation reaction pathway into a favorable process.