Biomimetic Synthesis Enables The Structure Revision Of Littordials E And F And Drychampone B

Structural reassignments for littordial E, littordial F, and drychampone B are proposed on the basis of consideration of their biosynthetic origin. The key step in the proposed biosynthesis of each of these meroterpenoids is an intermolecular heteroDiels-Alder reaction between an o-quinone methide and caryophyllene or humulene. Biomimetic total synthesis of the natural products gave sufficient material to allow their structure revision by NMR studies.