title: A new stereoselective synthesis of ciguatoxin right wing fragments.
abstract: The right wings (13 and 14) of ciguatoxins were synthesized highly stereoselectively. Key transformations in the synthesis are (i) an oxiranyl anion strategy to attach the H ring, (ii) intramolecular carbonyl olefination to cyclize the J ring, (iii) regio- and stereoselective reduction of the epoxyacetal to install the C42-stereocenter, and (iv) stereoselective reductive etherification to construct the K ring. The present procedure greatly improved the stereoselectivity and efficiency in comparison to a previous synthesis. Remarkably, only 23 steps were required from monocyclic I ring 5 to construct the ciguatoxin right wings. The high practicality of the present synthesis ensures a sufficient supply of these complex fragments for total syntheses and biomedical applications.
authors.affiliation: Department of Chemistry, Graduate School of Science, Tohoku University, Aramaki, Aoba-ku, Sendai 980-8578, Japan. inoue@ykbsc.chem.tohoku.ac.jp
authors.forename: Masayuki
authors.initials: M
authors.lastname: Inoue
authors.forename: Shuji
authors.initials: S
authors.lastname: Yamashita
authors.forename: Atsushi
authors.initials: A
authors.lastname: Tatami
authors.forename: Keisuke
authors.initials: K
authors.lastname: Miyazaki
authors.forename: Masahiro
authors.initials: M
authors.lastname: Hirama
mesh_terms: D002922:Ciguatoxins / Q000138:chemical synthesis*; D008968:Molecular Conformation; D013237:Stereoisomerism
chemical_list: D002922:Ciguatoxins