ABSTRACT
Marine polycyclic ether natural products are known to be the secondary metabolites of unicellular algae, mainly dinoflagellates. This chapter provides an overview of the total synthesis of gambierol. The Sasaki/Tachibana group was the first to accomplish the total synthesis of gambierol. The Sasaki group successfully assembled the entire polycyclic ether framework of gambierol in a highly convergent manner. The Kadota/Yamamoto group relied on intramolecular alkylation of -acyloxy ethers and ring-closing metathesis (RCM) for the synthesis of polycyclic ethers. Subsequent RCM completes the synthesis of polycyclic ether XIV. The Kadota/Yamamoto group coupled the ABC- and FGH-ring fragments and completed the octacyclic skeleton of gambierol by exploiting their intramolecular alkylation/ RCM methodology. The RCM of olefinic esters proceeds via the intermediacy of titanium alkylidene complex, whose formation is a prerequisite for the productive RCM pathway. The gross structure and relative stereochemistry of gambierol were established through extensive 2D nuclear magnetic resonance spectroscopic analyses.
