Collective Asymmetric Total Synthesis of Cylindricines.

Collective asymmetric total synthesis of marine tricyclic alkaloids, cylindricines A-H, and the proposed structures of cylindricines I and J was achieved in a concise manner from a single common spirocyclic pyrrolidine intermediate. A tandem chemoselective oxidation/intramolecular aza-Michael addition/epimerization was exploited to complete the tricyclic skeleton. This work provides a versatile synthetic entry to the cylindricine family of marine tricyclic alkaloids.