Enantioselective Synthesis of the Molluscicidal Furanosesquiterpene Lactones Ricciocarpin A and Ricciocarpin B via Ring Closing Metathesis

Using two catalytic ring closing metatheses as the key events, a short, completely diastereoselective and highly enantioselective access to the molluscicidal sesquiterpenoids ricciocarpin A and ricciocarpin B was achieved. The hitherto unknown absolute configuration of these natural products is unambiguously established.