Straightforward assembly of the octahydroisoquinoline core of morphinan alkaloids.

The octahydroisoquinoline core of morphinan was assembled starting from readily available arylcyclohexadienes. Three different approaches were developed, including a metal- and an acid-mediated Mannich type process and an anionic-mediated cyclization. All provided the desired motif as a single diastereomer having a C9−C13−C14 trans−cis relative configuration.