title: Total synthesis of ciguatoxin and 51-hydroxyCTX3C.
abstract: Ciguatoxins, the principal causative toxins of ciguatera seafood poisoning, are large ladder-like polycyclic ethers with the 13 ether rings ranging from five- to nine-membered. In this paper, we describe the total synthesis of the two most toxic members of the ciguatoxin family, ciguatoxin 1 and 51-hydroxyCTX3C 2, based on a unified synthetic strategy. The key features in our syntheses were (i) direct construction of the O,S-acetal from the corresponding left and right wing fragments (3, 4, 14); (ii) stereo- and chemoselective radical reaction of the alpha-oxyradical with pentafluorophenyl acrylate to achieve cyclization of the seven-membered G-ring; (iii) ring-closing metathesis reaction to build the nine-membered F-ring; and (iv) an efficient protective group strategy using the oxidatively removable 2-naphthylmethyl groups.
authors.affiliation: Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan. inoue@ykbsc.chem.tohoku.ac.jp
authors.forename: Masayuki
authors.initials: M
authors.lastname: Inoue
authors.forename: Keisuke
authors.initials: K
authors.lastname: Miyazaki
authors.forename: Yuuki
authors.initials: Y
authors.lastname: Ishihara
authors.forename: Atsushi
authors.initials: A
authors.lastname: Tatami
authors.forename: Yuyu
authors.initials: Y
authors.lastname: Ohnuma
authors.forename: Yuuya
authors.initials: Y
authors.lastname: Kawada
authors.forename: Kazuo
authors.initials: K
authors.lastname: Komano
authors.forename: Shuji
authors.initials: S
authors.lastname: Yamashita
authors.forename: Nayoung
authors.initials: N
authors.lastname: Lee
authors.forename: Masahiro
authors.initials: M
authors.lastname: Hirama
mesh_terms: D002922:Ciguatoxins / Q000138:chemical synthesis*; D015394:Molecular Structure
chemical_list: C466859:51-hydroxyciguatoxin 3C; D002922:Ciguatoxins