Total Synthesis of (-)-Pavidolide B: A Ring Contraction Strategy.

A ring contraction approach for the total synthesis of (-)-pavidolide B was developed, which assembles this polycyclic natural product within 13 steps from known chiral alcohol 11. The key features of the strategy include (a) a double Mukaiyama-Michael addition/elimination, (b) a ring-closing metathesis, (c) a Wolff rearrangement, and (d) a late-stage regioselective Schenck ene reaction.