Highly Substituted Oxabicyclic Derivatives from Furan: Synthesis of (±)-Platensimycin

A stereocontrolled approach to a key platensimycin intermediate was achieved from a commercially available furylcarboxylate. Key to our approach is the highly efficient formal [4 + 3] cyclocondensation of a substituted furan with tetrabromocyclopropene along with an intramolecular gamma-alkylation to construct the final ring of the caged intermediate.