104(P-61) ナカドマリンAの合成研究(ポスター発表の部)

概要

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The alkaloid, nakadomarin A has been isolated from the okinawan marine sponge Amphimedon sp. by Kobayashi in 1997. Although nakadomarin A is a member of manzamine family, it has a unique structure consisting of unprecedented 8/5/5/5/15/6 ring system containing a furane ring. Because of our interest to its unique ring system and also a need for enough quantity for full biological test, we started the synthesis of nakadomarin A. Two our synthetic approaches to the central core ring system of nakadomarin A will be reported. Route A consists of Diels-Alder reaction of chiral dienophile 9 and siloxydiene 2 to give a 6/6 AB ring system (10), followed by conversion to 5/5/6 ABD ring system (17) by ozonolysis and intramolecular aldol reaction. Route B is an efficient route for the synthesis of racemic ABCD ring system (31 and 37). A key step was intramolecular cyclization of a furane ring to acyl iminium cation. Ring closing metathesis of diene 39 to construct ring F will also be discussed.
天然有機化合物討論会の論文
2001-09-01