| Project/Area Number |
10208213
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| Research Category |
Grant-in-Aid for Scientific Research on Priority Areas (B)
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| Allocation Type | Single-year Grants |
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| Research Institution | Kyushu University |
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Principal Investigator |
KANEMASA Shuji INSTITUTE OF ADVANCED MATERIAL STUDY, KYUSHU UNIVERSITY, PROFESSOR, 機能物質科学研究所, 教授 (20038590)
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| Project Period (FY) |
1998 – 2000
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥10,900,000 (Direct Cost: ¥10,900,000)
Fiscal Year 2000: ¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 1999: ¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 1998: ¥3,700,000 (Direct Cost: ¥3,700,000)
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| Keywords | conformational control of the shielding substituents / torelant chiral Lewis acid catalysts / strongly coordinating nucleophiles / enantioselective 1,3-dipolar cycloadditions / enantioselective conjugate additions / nitrone cycloaddition reactions / diazo cycloaddition reactions / amine conjugate addition reactions / グリーンケミストリー / 力量ある合成手法 / 非会合性のルイス酸触媒 / 高い触媒活性 / 微粒子表面修飾型錯体触媒 / ビスオキサゾリン / スルフィド配位子 / 遮蔽基配座制御 / ビスオキサゾリン配位子 / 亜鉛錯体触媒 / マグネシウム錯体触媒 / ジアゾ1,3-双極性環状付加反応 / トリメチルシリルジアゾメタン / キラル配位子とアキラル補助基との協同効果 / 不斉ルイス酸触媒 / 3座トランス配位子 / ビナフトール配位子 / 遷移金属錯体 / ヘテロDiels-Alder反応 / 不斉共役付加反応 |
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| Research Abstract |
Development of a useful method of chirality control in catalyzed asymmetric reactions is one of the central subjects in the field of synthetic organic chemistry in 21st century. In the present research, we have challenged to design and synthesize efficient chiral catalysts based on conformational control of ligang skeleton as well as shielding substituents. One is a trans-chelating tridentate chiral ligand which has a dibenzofuran skeleton with two oxazoline substituents at 4- and 6-positions. The other one is a usual bisoxaloline type of chiral ligand having benzyl shielding substituents with o-hydroxyl moiety. These complexes are found to be effectively utilized in the catalyzed asymmetric reactions of strongly coordinating nucleophiles.
1. Nitrone Cycloadditions : The nickel(II) aqua complex of R,R-DBFOX/Ph ligand successfully catalyzes the nitrone cycloaddition reactions to 3-crotonoyl-2-oxazolidinone and derivatives in the catalytic loading of 2 mol% at room temperature to show ext
… More
remely high diastereo- and enantioselectivities.
2. Nitrone Cycloadditions Using Monodentate Dipolarophiles : The nitrone cycloaddition reactions using bromoacrolein as a monodentate dipolarophile proceed much more efficiently in the presence of the zinc(II) complexes of R,R-DBFOX/Ph ligand. It has been evidenced that this reaction proceeds through the internal delivery mechanism of the nitrone/catalyst/acceptor activated complex.
3. Diazo Cycloadditions : Excellent enantioselectivity has been attained in the diazo cycloaddition reactions between trimethylsilyldiazomethane and 3-crotonoyl-2-oxazolidinone and derivatives in the presence of the zinc(II) complexes of R,R-DBFOX/Ph ligand (10 mol%). On the other hand, similar reactions of 3-crotonoyl-4,4-dimethyl-2-oxazolidinone can be activated not by the zinc(II) and nickel(II) complexes at all but the magnesium complex. The high enantioselectivities with the opposite mode have resulted.
4. Amine Conjugate Additions : The copper(II) complex of R,R-BOX/o-HOBn ligand is found to be very useful in the amine conjugate addition reactions of O-benzylhydroxylamine to 3-isopropyl-1-crotonoyl-2-imidazolidinone. This reaction is also believed to proceed through the internal delivery mechanism. Less
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