Synthesis of the ABCD domain of the azaspiracids

This thesis describes synthetic efforts toward the total synthesis of the azaspiracid marine toxins. The investigation here focuses on the synthesis of the ABCD bis-spiroketal domain. Several different approaches have been developed. One features a gold catalyzed spiroketalization, which used a triple bond as an oxidation-state equivalent of a ketone to establish a spiroketal structure. In the D-ring synthesis, a Co(modp)2 (modp: 1-mophorlinocarbamoyl-4,4-dimethyl-1,3-pentadione) catalyzed oxyetherification was applied. In the recently revised synthetic route, the D-ring was constructed through a tandem asymmetric epoxidation and epoxide opening process.