| Project/Area Number |
17550102
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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 |
Synthetic chemistry
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| Research Institution | Osaka University |
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Principal Investigator |
YASUDA Makoto Osaka University, Graduate School of Engineering, Associate Professor, 大学院・工学研究科, 助教授 (40273601)
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| Project Period (FY) |
2005 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2006: ¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 2005: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Keywords | Lewis acid / Indium / Boron / Silicon / Cage-Shape / Steric Effect / Selectivity / Catalyst |
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| Research Abstract |
A structurally strained borate was generated in the reaction of tris(2-hydoxyphenyl)methane with borane. The formed boron species has a cage-shape and a pyramidal structure around the boron metal. The cage-shape and structural strain enhance the Lewis acidity and catalytic turn-overs. The cage-shaped borate catalyzed the allylation of benzaldehyde with allyltributyltin, while phenyl borate B(OPh)_3,which has a planar structure, did not show catalytic acitivity. Its pyridine complex was analyzed by NMR which shows strong interaction of the borate with pyridine and a tetrahedral structure around the metal. The pyridine complex in solid state was characterized by X-ray crystallography. Boron has a tetrahedral coordination sphere with the average of bond angles (O-B-O,114.2(9)° and N-B-O,104.1(9)°). The structure without pyridine shows C_3 symmetry. The aromatic rings deviate from a perpendicular plane to that of three oxygens (ca.19.2°) and thus, the pyridine-complex has chiality that is caused by the cage-shape.
The combined Lewis acid system using indium and silicon showed very high activity of some reactions. An NMR study clearly showed the interaction of the indium with silicon mediated by Cl as a bridged atom. The high Lewis acidity showed up on the silicon center in situ. The high oxophilicity accelerated the direct subsitution of alcohols in a catalytic manner. The catalyst system accomplished the catalytic substitution of alcohols in a halogen-free solvent. The system is considered to be an ideal and practical process for industrial chemisty.
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