UC Irvine

The first chapter of this thesis details our development of a methodology to control π-facial selectivity in intramolecular Diels–Alder cyclizations using a silacycle directing group. The genesis of this project, stemming from a recent total synthesis project in our lab, is discussed. A panel of substrates is synthesized and tested, providing insight into the capabilities and, more importantly, the limits of the methodology. Deeper mechanistic insight is gained through a deuterium-labelling study, the details of which are discussed. Finally, a selection of products delivered using this methodology are shown to be apt for further synthetic derivatization. The second chapter of the thesis presents our ongoing synthetic approach to a pair of Artemisia sesquiterpenoids, artatrovirenols A and B. The isolation and characterization of these natural products is discussed as well as the isolation chemists’ proposed biosynthetic pathway. We discuss the logic of our synthetic approach, which incorporates an intramolecular Diels–Alder cyclization proposed by the isolation chemists as the key step. An initial synthetic route is investigated and discussed, but ultimately abandoned as a key Nazarov cyclization proved to be impractical. A revised synthetic route is devised and discussed, using α-santonin as the starting material. Some preliminary experiments to probe the viability of the key Diels–Alder connection are reported, without success thus far.