438002-48-3Relevant academic research and scientific papers
Intramolecular radical cyclization - Ring-closing metathesis approach to fused polycyclic ethers. Convergent synthesis and conformational analysis of the (E)FGH ring system of ciguatoxin
Sasaki, Makoto,Noguchi, Tetsuji,Tachibana, Kazuo
, p. 3301 - 3310 (2007/10/03)
A convergent synthetic route to the (E)FGH ring system 4 of ciguatoxins, the causative toxins for ciguatera fish poisoning, has been developed. The synthesis features convergent coupling to form dioxane acetal, regioselective acetal cleavage by diethylaluminum phenylthiolate or diisobutylaluminum phenylselenolate followed by intramolecular radical cyclization to construct the oxepane ring G, and a ring-closing metathesis reaction to form the hexahydrooxonine ring F. The hexahydrooxonine ring F of tetracyclic model system 4 existed as a 5:1 equilibrium mixture of two conformers (UP and DOWN conformers), with the UP one predominating. This is the first illustration that reproduces the preference for the UP conformer over the DOWN one, which preference was observed for natural ciguatoxins.
Synthesis of the FGH ring fragment of ciguatoxin
Sasaki,Noguchi,Tachibana
, p. 1337 - 1340 (2007/10/03)
Stereoselective synthesis of the FGH ring fragment of ciguatoxin is described. The key steps in the present synthesis are an intramolecular radical cyclization to construct oxepane ring G and ring-closing metathesis reaction to construct hexahydrooxonin ring F.
