Development of a unified strategy for the syntheis of enmein-type ent-kauranoids

Abstract

Development of a unified strategy for the total synthesis of the enmein-type ent-Kauranoids is disclosed. A total synthesis campaign of this class of natural products is of particular interest due to the potent anti-proliferative activity of these natural products across a wide range of cancer cell lines. The synthetic strategy described relies upon formation of the central lactone unit through a challenging reductive crosselectrophile coupling reaction. This route is highly convergent, as it assembles the reductive coupling substrate through an esterification reaction of a stereochem.-rich epoxy alc. with a structurally complex [3.2.1|-bicyclooctane. The epoxy alc. can be assembled through a diastereoselective oxidn. sequence while the [3.2.1|-bicyclooctane can be prepd. through a gold-catalyzed Conia-ene reaction. The modularity of this synthesis can potentially provide access to a wide range of natural products with varying backbone functionalization. Current efforts directed toward the development of key reactions in this sequence and their application to the synthesis of these products will be presented.