Biomimetic alloxan-catalyzed intramolecular redox reaction with O2: One-pot atom-economic synthesis of sulfinyl-functionalized benzimidazoles.

• Developing biomimetic alloxan-catalyzed intramolecular redox reaction with O 2. • The process underwent two oxidations under mild and metal-free reaction conditions. • The environmentally benign molecular oxygen as the only sacrificial reagent. • One-pot atom-economic synthesis of various sulfinyl-functionalized benzimidazoles. Given the necessity of sacrificial reductants in various biomimetic aerobic oxygenations, alloxan-catalyzed aerobic redox system for one-pot atom-economic synthesis of sulfinyl-functionalized benzimidazoles was developed by ingeniously binding both the substrate sulfide and sacrificial reductant. This mild and transition-metal-free protocol undergoes two oxidations without additional sacrificial reagents, except for the environmentally benign molecular oxygen. [ABSTRACT FROM AUTHOR]