Studies toward the synthesis of yaretol: an unexpected rearrangement en route to the tricyclic core

Yaretol is a polycyclic norditerpene constituting a structurally distinct class of terpene natural products isolated from Azorella madreporica which, to date, has not been accessed via total synthesis. Herein, we report our synthetic efforts toward a key intramolecular Diels-Alder furan (IMDAF) cycloaddition to construct the carbon framework. We discuss our efforts toward the cycloaddition wherein undesired aromatization and unanticipated rearrangement of the cycloadduct are observed.