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 hetero-Diels-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.Tomás Vieira de Castro, Oussama Yahiaoui, Ricardo A. Peralta, Thomas Fallon, Victor Lee and Jonathan H. Georg