Chemoenzymatic Synthesis of the Enantiomer of 4,12-Dihydroxysterpurene, the Structure Assigned to a Metabolite Isolated from the Culture Broth of <i>Stereum purpureum</i>

Compound ent-1 has been prepared by engaging a derivative of the enantiomerically enriched and microbially derived cis-1,2-dihydrocatechol 6 in an intramolecular Diels–Alder reaction, elaboration of the adduct so-formed to the cyclopentannulated bicyclo[2.2.2]­octenone 3, and photochemical rearrangement of this to the cyclobutanone 2. By such means it has been established that 4,12-dihydroxysterpurene (1) is not the structure of the natural product isolated by Xie and co-workers from a culture broth of Stereum purpureum.