A convergent synthesis of the trans-fused hexahydrooxonine ring system and reproduction of conformational behavior shown by ring F of ciguatoxin

Article abstract of DOI:10.1016/S0040-4020(99)00620-1

A new strategy for the construction of the fused hexahydrooxonine ring system has been developed. The present synthesis involves an intramolecular reaction of γ-alkoxyallylsilane with acetal to form an O-linked oxacycle and a SmI₂-mediated intramolecular Reformatsky reaction for constructing an oxonane ring as the key steps. Thermodynamic behavior of the trans-fused hexahydrooxonine ring was clarified for the first time and the conformational alternation was reproduced in the 6-9-6 tricyclic model compound 1 as was observed for that in the ciguatoxin molecule (ring F).