The EF-ring of ciguatoxin 3C, a marinetoxinfrom the dinoflagellateGambierdiscustoxicus, was stereoselectively synthesized by iterative use of a cyclic ether formation process based on chirality-transferring Ireland-Claisen rearrangement and ring-closing olefin metathesis.
synthesis of the ABCDEF-ring of ciguatoxin 3C was achieved via a route that included anion coupling of a dimethyldithioacetal mono-S-oxide derivative corresponding to the AB-ring and an aldehyde corresponding to the EF-ring, followed by cyclization using reductive etherification. The AB-ring was synthesized from a known d-glucosederivative based on ring-closing olefin metathesis, and the EF-ring was prepared