Stypolactone, an interesting diterpenoid from the brown alga Stypopodium zonale

A new diterpenoid of mixed biogenesis, stypolactone 8, containing a tricyclic terpenoid moiety which in combination with its spirolactone ring, leads to a novel carbon skeleton, has been isolated from the brown alga Stypopodium zonale. It's structure and relative stereochemistry were established by spectroscopic evidence and biogenetic considerations. (C) 2002 Elsevier Science Ltd. All rights reserved.