| Project/Area Number |
18550098
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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 | Aoyama Gakuin University |
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Principal Investigator |
TAKEUCHI Ryo Aoyama Gakuin University, College of Science and Engineering, Professor (00216871)
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| Co-Investigator(Kenkyū-buntansha) |
ONODERA Gen Aoyama Gakuin University, College of Science and Engineering, Assistant (90433698)
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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 |
¥4,120,000 (Direct Cost: ¥3,700,000、Indirect Cost: ¥420,000)
Fiscal Year 2007: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Fiscal Year 2006: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Keywords | iridium / allylic alkylation / asymmetric synthesis / phosphoramidite / cyclotrimerization / regioselectivity |
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| Research Abstract |
We have studied the following reactions.
(1) Asymmetric allylic alkylation is one of the most powerful tools for constructing a new chiral center via a carbon-carbon bond-forming reaction from an achiral substrate. A challenging topic in this area is the regio- and enantioselective allylic alkylation of nonsymmetrical substrates. Chiral phosphoramidite ligands have become important in transition metal-asymmetric synthesis. Helmchen first used binaphthol-based phosphoramidites for iridium-catalyzed enantioselective allylic alkylation. We designed a novel phosphoramidite P(OR)_2(amide)ligand. The planarity of the amide group strongly contributes to a more rigid chiral space. Furthermore, such a phosphoramidite ligand is expected to act as a chiral bidentate ligand through coordination of the carbonyl oxygen and phosphorous atom to the central metal. The efficiency of the ligand was examined by the reaction of cinhamyl acetate with diethyl sodiomalonate in the presence of 2 mol% of [Ir(cod)Cl]_2 and 4 mol% of ligand. The best result was obtained with a ligand bearing an oxazolidinone moiety. The alkylated product was obtained in 94% yield with 93% ee without LiCl.
(2) Polysubstituted benzenes are a common structural component of naturally occurring biologically active molecules. The regioselective cyclotrimerization of two or three different monoynes is a new and efficient route to polysubstituted benzenes. However, it can be difficult to control the regioselectivity. Methyl propiolate reacted with 2 molecules of 1-alkyne to give 3, 5-disubstituted benzoate in high yield in the presence of a catalytic amount of [Ir(cod)Cl]_2 and FDPPE. The reaction of ethynyl p-tolyl sulfone with various 1-alkynes gave the corresponding products in high yields
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