Synthesis of (±)-aphanorphine: a new approach to tricyclic 3-benzazepine scaffold using two radical C–C bond-forming reactions

An expeditious approach to (±)-aphanorphine has been established using readily available starting materials. The present synthesis relies on the direct assembly between N-methylpyrrolidone (NMP) and 2-bromoanisaldehyde, which takes place through Et3B/air-mediated transformation of the α-nitrogen-substituted sp3C–H bond, and features a new design concept for the synthesis of the tricyclic 3-benzazepine skeleton.