Total Synthesis of (+)-7,7'-Bistaxodione via Late-Stage Electrochemical Dimerization

The first asymmetric total synthesis of the tetraterpenoid (+)-7,7'-bistaxodione (4a) via a unique late-stage electrochemical oxidative dimerization of a diterpenoid quinone methide tumor Inhibitor (+)-taxodione (3a) has been described. The naturally occurring monomer 3a was synthesized from aromatic abietane diterpenoid, ferruginol (1e) . Further, an efficient convergent synthetic route toward the naturally occurring aromatic abietane terpenoids has been shown via a Lewis acid-mediated diastereoselective cationic epoxy-ene cyclization. This synthetic method directly allows for the formation of a functionalized aromatic abietane scaffold with four contiguous stereogenic centers (two of which are all-carbon quaternary centers).