Diastereoselective synthesis of N-Boc-norpandamarilactonine-B and pandamarilactonine-A.

Optically pure N-Boc-norpandamarilactonine-B was diastereoselectively synthesized starting from L-serine by employing a double ring closing metathesis (RCM) of a tetraene derivative as a key reaction. N-Boc-norpandamarilactonine-B obtained was further converted to pandamarilactonine-A.