Total Synthesis of (–)-HM-3 and (–)-HM-4 Utilizing a Palladium-Catalyzed Addition of an Arylboronic Acid to an Allenic Alcohol Followed by Eschenmoser–Claisen Rearrangement

Abstract

The first asymmetric total synthesis of (–)-HM-3 and (–)-HM-4, aromatic sesquiterpenes isolated from the phytopathogenic fungus <i>Helicobasidium mompa</i>, has been achieved. Highlight of the synthesis is an enantiospecific construction of the quaternary carbon stereocenter utilizing a palladium-catalyzed addition of arylboronic acid to the allenic alcohol followed by Eschenmoser–Claisen rearrangement.