Studies directed toward the synthesis of hedycoropyrans: total synthesis of des-hydroxy (—)-hedycoropyran B (ent-rhoiptelol B)

A full account of our efforts directed towards the synthesis of diarylheptanoid-derived natural products hedycoropyrans that led to the total synthesis of ent-rhoiptelol B is described. In this endeavor, we have attempted two distinct synthetic strategies to access hedycoropyrans A and B, which led us to establish a facile synthetic route for des-hydroxy (—)-hedycoropyran B (ent-rhoiptelol B) from simple and readily accessible building blocks of 4-allylanisole and vanillin employing Sharpless asymmetric epoxidation, CBS-reduction, and intramolecular AgOTf-catalyzed oxa-Michael reaction of suitably functionalized hydroxy-ynone as key transformations.