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.
ASJC Scopus subject areas
- Organic Chemistry