title: Synthetic study of azaspiracid-1: synthesis of the EFGHI-ring fragment.
abstract: Here, we report a synthesis of the lower half C21-C40 fragment of the shellfish toxin, azaspiracid-1. The C28-C40 fragment was synthesized by a coupling between the C28-C35 epoxide and the C36-C40 dithioacetal anion, followed by the HI-ring spiroaminal formation. An aldehyde corresponding to the C28-C40 fragment was then coupled with the C21-C27 allylic stannane by using InCl3. Finally, the FG-ring was constructed by HF.pyridine to accomplish the synthesis of the suitably protected C21-C40 fragment.
authors.affiliation: Laboratory of Biostructural Chemistry, Graduate School of Life Sciences, Tohoku University, Tsutsumidori-amamiya, Aoba-ku, Sendai 981-8555, Japan. mao@bios.tohoku.ac.jp
authors.forename: Masato
authors.initials: M
authors.lastname: Oikawa
authors.forename: Tomoko
authors.initials: T
authors.lastname: Uehara
authors.forename: Taizo
authors.initials: T
authors.lastname: Iwayama
authors.forename: Makoto
authors.initials: M
authors.lastname: Sasaki
mesh_terms: D008387:Marine Toxins / Q000138:chemical synthesis*; D015394:Molecular Structure; D013141:Spiro Compounds / Q000138:chemical synthesis*; D000095702:Polyether Toxins
chemical_list: D008387:Marine Toxins; D013141:Spiro Compounds; C406592:azaspiracid; D000095702:Polyether Toxins