Synthesis and absolute configuration of three natural ent-halimanolides with biological activity

The first three natural ent-halimanolides known until now have been synthesized from ent-halimic acid. Their structure have been confirmed as well as their absolute configurations established. Bestmann methodology has been used for the synthesis of butenolides and for the γ-hydroxybutenolides synthesis the Boukouvalas method has been employed. Biological testing has been carried out on these compounds.