1992 Fiscal Year Final Research Report Summary
Synthetic Studies of Cotylenol, Having Plant Growth Activity, and the Related Biogenetically Active Terpenoids.
Project/Area Number |
03640475
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Research Category |
Grant-in-Aid for General Scientific Research (C)
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Allocation Type | Single-year Grants |
Research Field |
天然物有機化学
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Research Institution | KYUSHU UNIVERSITY |
Principal Investigator |
KATO Nobuo Kyusyu University, Institute of Advanced Material Study, Assistant., 機能物質科学研究所, 助手 (50150537)
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Project Period (FY) |
1991 – 1992
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Keywords | Terpenoid Synthesis / Formation of 8-Membered Ring / Cotylenol / Plagiospirolide / Sordaricin / Biological Diels-Alder Reaction |
Research Abstract |
1. It has been proved that a diterpenoid named sordaricin (1) is biosynthesized from its congener, hydroxycycloaraneosene (2). From the structural relationships between 1 and 2, the biogenesis of 1 must involve an oxidative ring-fission of the central 8-membered ring of 2 followed by an intra-molecular Diels-Alder reaction of resulted cyclopentadiene and unsaturated aldehyde moieties. The synthetic studies utilizing of this Diels-Alder reaction have accomplished the first total synthesis of methyl ester derivative of 1. 2. The total synthesis of fusicocca-2,5-diene (3), a 5-8-5-membered tricyclic diterpene, has been accomplished. Although 3 has not been isolated yet, several terpenoids are considered to be biosynthesized from 3. Plagiospilolides A and B (4,5), metabolites of the liverwort, are the Diels-Alder products from 3 and the sesquiterpene lactones, diplophyllolide (6) and diplophyllin (7), respectively. In fact, the Diels-Alder reactions between 3 and totally synthesized 6 and 7 gave 4 and 5, respectively, with high stereoselectivities. With this total synthesis, the absolute configurations of 4 and 5 have been deduced. 3. A synthetic problem for the total synthesis of cotylenol (8) laid in the control of the stereochemistry of an 8,9-glycol moiety. To overcome this problem, two synthetic routes were investigated. Although the reductive cyclization of dial-precursors failed to control the stereochemistries of this glycol function, the 'ene'-cyclization procedure gave several encouraging results. The later process has provided not only the method of controlling the stereochemistries but also the method of converting 3-hydroxyl group, which is deeply related with an instability of 8, to a thiol moiety.
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Research Products
(8 results)