Cyclobutane-Containing Meroditerpenoids, (+)-Isoscopariusins B and C: Structure Elucidation and Biomimetic Synthesis

(+)-Isoscopariusins B () and C (), two meroditerpenoids containing a 6/6/4 tricyclic carbon skeleton and seven continuous stereocenters, were identified from . The structures were determined by nuclear magnetic resonance analysis and concise biomimetic syntheses from readily available alkene in seven and six steps, respectively. An intermolecular [2+2] photocycloaddition with cooperative catalysis of a Lewis acid and an Ir photocatalyst was used to construct a cyclobutane core with four stereogenic centers.