| Tetrahydrofurans (thf) and tetrahydropyrans (thp) are important structural motifs found in a broad array of biologically relevant natural products such as polyether antibiotics and acetogenins. Classic methods used for thf- or thp-ring synthesis have their own advantages and disadvantages which tend to be substrate specific. Therefore, development of new and efficient methods is imperative especially to address the issue of diastereoselectivity when attainment of both cis- and trans-2,5-thf (or 2,6-thp) is highly desirable.;Herein, a strategy of cross-metathesis and Pd(0)-catalyzed cyclization, useful for obtaining both cis- and trans-2,5-disubstituted thf (or 2,6-disubstituted thp), will be discussed along with its application in the synthesis of amphidinolide C and oxylipids. Amphidinolide C, a complex macrolide isolated from Okinawan marine dinoflagellates, exhibits in vitro cytotoxicity against human skin cancer cells at a low nano-molar range. Oxylipids isolated from Australian brown algae show strong activity against parasitic nematodes. This dissertation embodies investigations, synthetic efforts, and insights in achieving the total synthesis of these marine natural products. |
