title: Total synthesis of brevetoxin B.
abstract: The convergent total synthesis of brevetoxin B (1) has been achieved. The intramolecular allylation of the O,S-acetal 20, prepared from the alpha-chlorosulfide 17 and the alcohol 5, was carried out using AgOTf as a Lewis acid to give the diene 21, predominantly. Ring-closing metathesis of 21 with the Grubbs catalyst 23 afforded the hexacyclic ether 25 which was converted to the A-G ring segment 2 through several steps. The intramolecular allylation of the alpha-acetoxy ether 42, prepared from 2 and the J-K ring segment 3, followed by ring-closing metathesis provided the polycyclic ether framework 44. A series of reactions of 44, including oxidation of the A ring, deprotection of the silyl ethers, and selective oxidation of the resulting allylic alcohol, furnished 1.
authors.affiliation: Research and Analytical Center for Giant Molecules, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan. ikadota@mail.tains.tohoku.ac.jp
authors.forename: Isao
authors.initials: I
authors.lastname: Kadota
authors.forename: Hiroyoshi
authors.initials: H
authors.lastname: Takamura
authors.forename: Hiroki
authors.initials: H
authors.lastname: Nishii
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Yamamoto
mesh_terms: D008387:Marine Toxins / Q000138:chemical synthesis*; D008968:Molecular Conformation; D035964:Oxocins / Q000138:chemical synthesis*; D013237:Stereoisomerism; D000095702:Polyether Toxins
chemical_list: D008387:Marine Toxins; D035964:Oxocins; C043466:brevetoxin B; D000095702:Polyether Toxins