| Project/Area Number |
18590007
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Chemical pharmacy
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| Research Institution | Kumamoto University |
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Principal Investigator |
NAKAJIMA Makoto Kumamoto University, Faculty of Medical and Pharmaceutical Sciences, Professor (50207792)
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| Project Period (FY) |
2006 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥3,880,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥480,000)
Fiscal Year 2007: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
Fiscal Year 2006: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Keywords | Organic chemistry / Synthetic chemistry / Catalysis / Organic industrial chemistry / Asymmetric synthesis / Phosnhine oxide / Allylation / Aldol reaction / リン酸化反応 / シリカート / 蝕愛 / 不斉合成反応 / シリルエノールエーテル / 立体選択性 |
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| Research Abstract |
Silicon atom expands its coordination sphere to give relatively stable penta- or hexa-coordinated compound, or "hypervalent silicate" due to its vacant 3d-orbital. Since these extracoordinated species are powerful intermediates with abundant reactivities, remarkable developments have been made on various organic reactions based on this unique mechanism. We investigated the base-promoted asymmetric catalyses wherein bases coordinated with silicon atoms to form hypervalent silicates. We found that chiral lithium binaphtholate catalyzed the aldol reaction of trimethoxysilyl enol ethers, which realized the construction of quaternary carbon center using tetra-substituted silyl enol ethers. With this protocol, the highest synlanti selectivity was obtained in the construction of quaternary carbon center using asymmetric aldol reaction. We also found that chiral phosphine oxides catalyzed the aldol reaction of trichlorosilyl enol ethers, wherein complete stereochemical correlation is observed between the diastereomeric ratio (synlanti) of the products and the geometries (E/Z) of the trichlorosilyl enol ethers. This methodology was extended to the direct aldol reaction, the aldol reaction between two carbonyl compounds, not using silyl enol ether as an aldol donor. Phosphine oxides coordinated with tetrachlorosilane to afford more acids complexes than tetrachlorosilane itself, which were efficiently utilized in Lewis acid-catalyzed asymmetric reactions. With this concept, catalytic amounts of chiral phosphine oxides activated tetrachlorosilane to promote the Abramov-type phosphonylations of aldehyde with trialkyl affording the corresponding hydroxyphophonates, which exhibited the first asymmetric version of this type of reaction.
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