Total synthesis of (±)-auranthine confirmed its refined structure.

Auranthine, isolated in 1986 from Penicillium aurantiogriseum , is a fungal benzodiazepine. Through the successful total synthesis of (±)-auranthine, we confirmed the refined structure of natural (-)-auranthine. We established that natural (-)-auranthine is a fused quinazolino benzodiazepine dione 1 featuring an acyclic aliphatic nitrile moiety, thereby disproving the proposed structure 2.