1994 Fiscal Year Final Research Report Summary
High-Order Use of Reactive Intermediates Stabilized by Oxygen Atom
| Project/Area Number |
05671752
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Chemical pharmacy
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| Research Institution | Osaka University |
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Principal Investigator |
FUJIOKA Hiromichi Osaka University, Faculty of Pharmaceutical Sciences, Associate Professor, 薬学部, 助教授 (10173410)
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| Project Period (FY) |
1993 – 1994
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| Keywords | cationic species / intermediate in Beckmann fragmentation / endo-brevicomin / d-(R)-lipoic acid / dioxenium cation / orthoester / polyol / polysubstituted tetrahydrofuran |
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| Research Abstract |
In this project, we studied on high-order use of i) the reactive intermediates in Beckmann fragmentation reaction and ii) the dioxenium cations formed by acid treatment of orthoesters.
i) The Beckmann fragmentation is one of the long-known reactions and used widely in organic synthesis. Although the reactive intermediates in the Beckmann fragmentation of the corresponding alpha-alkoxycycloalkanone oxime derivatives are very active electrophiles, only a limited kind of nucleophiles such as H2O,ROH,halide anion and carbon ones have been used so far. As the organic synthesis utilizing the intermediates of Beckmann fragmentation, we developed new carbon-carbon bond forming reactions using silicon-containing carbon nucleophiles and organoaluminium reagents. As an extention of the reactions, we also succeeded in developing a novel asymmetric carbon-carbon bond formation by combination of Beckmann fragmentation reaction and asymmetric synthesis using a chiral acetal and a highly stereoselective carbon-carbon bond formation in the reaction of 2,3-isopropyridenedioxycyclohexanone oxime esters with organpaluminium reagents.
ii) Orthoesters work as superior electrophiles by forming dioxenium cations We succeeded in a facile one-pot formation of oxacyclic compounds in the reaction of triols with trialkyl orthoesters in the presence of acid catalyst. The reaction was successfully applied to the unprotected high-order alcohols giving polysubstituted tetrahydrofurans in a one-pot synthesis.
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