A new stereoselective synthesis of ciguatoxin right wing fragments.
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.
Inoue
Masayuki
M
Department of Chemistry, Graduate School of Science, Tohoku University, Aramaki, Aoba-ku, Sendai 980-8578, Japan. inoue@ykbsc.chem.tohoku.ac.jp
Yamashita
Shuji
S
Tatami
Atsushi
A
Miyazaki
Keisuke
K
Hirama
Masahiro
M
D002922:Ciguatoxins / Q000138:chemical synthesis*; D008968:Molecular Conformation; D013237:Stereoisomerism
D002922:Ciguatoxins