Intricarene is an unprecedented trispiropentacyclic diterpene natural product. Recent studies have shown that intricarene carbon skeleton could arise biogenetically in a single cyclization step from the "cembrane" carbon framework. This proposal describes a biomimetic total synthesis of intricarene with the key cyclization step being an unprecedented transannular [5+2] oxidopyrylium alkene cycloaddition. This penultimate cyclization event will create the trispiropentacyclic framework along with four of the five contiguouis stereocenters of intricarene in a single synthetic operation. Molecular modeling was used to study the conformations of the marcocyclic "cembrane" precursor, justifying the possibility of a diastereoselective cyclization. [unreadable] [unreadable] [unreadable]