A Facile Asymmetric Route to (−)-Aphanorphine

8O-Methylaphanorphine was synthesized from 4-methoxyphenylacetaldehyde in 36% overall yield and in nine steps, featuring the formation of ring B via a Friedel−Crafts alkylative cyclization with the concomitant stereospecific introduction of the benzylic quaternary carbon center. The current work constitutes an efficient enantioselective formal synthesis of 3-benzazepine marine alkaloid (−)-aphanorphine.