Stereoselective synthesis of marine sesterterpenes, 16-deacetoxy-scalarafuran, (+)-scalarolide and their analogs

The stereoselective synthesis of C12 oxygenated marine scalaranic sesterterpenes 16-deacetoxy-scalarafuran, (+)-scalarolide and their unnatural analogs were described. Three key transformations were involved in their synthesis, which are the ring-opening rearrangement of epoxide, stereoselective Diels-Alder addition, and one-pot γ-butenolide formation process, and the absolute configurations of natural (+)-scalarolide and 16-deacetoxy-scalarafuran were confirmed.