Asymmetric Total Synthesis of (+)-Mannolide C.

(+)-Mannolide C is a complex hexacyclic C20 cephalotane-type diterpenoid featuring a highly strained 7/6/6/5 tetracyclic core containing eight consecutive stereocenters and two bridging lactones. The first asymmetric total synthesis of (+)-mannolide C has been accomplished by lipase-mediated resolution, Ru-complex-catalyzed double ring-closing metathesis (RCM) reactions, NiII -catalyzed diastereoselective Michael addition, and MnIII -catalyzed allylic oxidation as the key transformations.