A Unified Strategy to Plakortin Pentalenes: Total Syntheses of (±)-Gracilioethers E and F.

A unified route to oxygenated Plakortin pentalenes is described. Along with the previously disclosed total synthesis of hippolachnin A, the potential of this scheme is demonstrated by the first total synthesis of gracilioether E, as well as the total synthesis of gracilioether F. Key features of the unified synthetic strategy include the concise construction of common key intermediate 1 and a topological-strategy guided functionalization of a highly substituted cyclobutene providing efficient access to the core skeletons.