Enantioselective total synthesis of (+)-eupenoxide and (+)-phomoxide: revision of structures and assignment of absolute configuration.

[reaction: see text] Stereo- and enantioselective total syntheses of the novel, polyketide natural products ent-eupenoxide and ent-phomoxide have been accomplished from the readily available Diels-Alder adduct of cyclopentadiene and p-benzoquinone. These synthetic studies necessitate the revision of the assigned stereostructures of the natural products and reveal their absolute configuration.