Helminthosporol (1), and its tautomeric precursor, prehelminthosporol (2), are phytotoxic diterpenoid metabolites isolated from the fungi Bipolaris sativus and Bipolaris sorkiniana.   Helminthosporol (1) has shown inhibitory activity against acyl-CoA cholesterol acyltransferase (ACAT), an enzyme responsible for cholesterol uptake.  Minimized analogs lacking the hydroxyl, methyl, and exo-methylene substituents from the [3.2.1]-bicycloalkane core (3-5) are being prepared to evaluate structure/activity.  A common synthetic route to the analogs (3-5) involving a pivotal Darzens condensation / divinylcyclopropane rearrangement sequence is described.