UC Berkeley

This dissertation details our approaches toward the topologically complex natural products arcutinidine and septosone A. Chapter 1 is a comprehensive overview of the previous approaches toward the arcutane natural product scaffold by other groups. Particular attention is paid to the choices made by others in their retrosyntheses and how they affected the forward syntheses. This section also includes the proposals for the biosynthetic origin of the arcutane alkaloids from the hetidine-type diterpenoid alkaloids.

Chapter 2 describes our attempts to perform a contra-biosynthetic rearrangement from an arcutane-type to a hetidine-type skeleton in a model system. Although we were unsuccessful in effecting the desired transformation, it provided some interesting reactivity. This chapter also details the completion of the total synthesis of the diterpenoid alkaloid arcutinidine.

Chapter 3 gives an introduction to septosone A and related meroterpenoid natural products, specifically the dysifragilones and the dactyloquinones. It details the biological activity of septosone A and presents an in depth look into the biological pathway(s) responsible for the bioactivity. This chapter also describes the proposed biosynthetic origin of the septosones and related congeners. The syntheses of less complex tricyclic and tetracyclic meroterpenoids is discussed to provide context for the choices made in our retrosynthesis.

Chapter 4 details our synthetic efforts toward septosone A. After two unsuccessful approaches, success has been achieved toward the completion of four of the five rings in septosone A. Utilizing a Wieland–Miescher ketone derivative that was coupled to a functionalized phenyl ring, an intramolecular Heck cyclization forged the central five-membered ring. Investigations are ongoing to complete the septosone A scaffold. Although unanticipated at the onset, our studies provide access to the dysiherbol, dysifragilone, and dysidavarone meroterpenoid scaffolds.