Total Synthesisof (+)-7,7′-Bistaxodione viaLate-Stage Electrochemical Dimerization

The first asymmetric total synthesis of the tetraterpenoid (+)-7,7′-bistaxodione (<b>4a</b>) via a unique late-stage electrochemical oxidative dimerization of a diterpenoid quinone methide tumor Inhibitor (+)-taxodione (<b>3a</b>) has been described. The naturally occurring monomer <b>3a</b> 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).