A New Strategy toward the Total Synthesis of Stachyflin, A Potent Anti-Influenza A Virus Agent:  Concise Route to the Tetracyclic Core Structure

A new strategy directed toward the total synthesis of stachyflin, a potent and novel anti-influenza A virus agent isolated from a microorganism, has been presented through the enantioselective synthesis of the tetracyclic core structure. The synthetic method features a BF<sub>3</sub>·Et<sub>2</sub>O-induced domino epoxide-opening/rearrangement/cyclization reaction as the key step.