Generation of Highly Selective Tantalum Reagent from Organotin Reagents
| Project/Area Number |
11650895
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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 |
SHIBATA Ikuya Osaka University, Graduate School of Engineering, Associate Professor, 大学院・工学研究科, 助教授 (10196420)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2000: ¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1999: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Keywords | Organotin compounds / Transmetallation / Tantalum / Conjugate Addition / Tin Hydride / Reductive Amination / Nitrogen Heterocycles / Highly Selective Reaction / スズ / タンタル / 不飽和ケトン / 共役アリル化 |
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| Research Abstract |
Active and selective reagent could be generated based on organotin compounds by means of following methods(1)Generation of active tantalum reagents by transmetallation from tin compounds the their application to conjugate addition to enones. (2)Generation of active tin hydride by introducing an active substituent or a ligand onto tin center and their applications to chemo and regioselective reductions.
As a example of method 1, active allylic, tantalum could be generated by transmetallation between organotins and TaCl_5, and were found to be a versatile reagent for conjugate allylation of enones. Alkynyltin and benzyltin could also cause the conjugate addition. Moreover, TaCl_5 could be used as a catalyst in the presence of chlorotrimethylsilane which trapped the produced Ta enolate and regenerate TaCl_5.
Secondary, as a example of method 2, a tin hydride complex such as Bu_2SnClH-HMPA was developed which enable reductive amination of carbonyl compounds. The tin reagent particularly worked well for the case using weakly basic aromatic amines as starting substrates. Stoichiometric amounts of a substrate and a reducing agent were adequate for the reaction. The Sn-Cl bond in the complex plays an important role for both steps of imine formation and subsequent reduction. Highly chemoselectivereductive amination of carbonyls could be achieved regardless of other functionalities such as halogen, carbon-carbon double bond and hydroxyl groups in the starting carbonyls and amines. The reductive amination of aldehyde could be enlarged to the synthesis of various nitrogen heterocycles starting from the bifunctional substrates containing an aldehyde and enone groups. Moreover, a novel ate type complex of tin hydride Li^+[Bu_2SnI_2H]-could be developed and its structure was cleared by NMR spectra. The reaction using the ate complex afforded regioselective 1,4-reductinn of enals.
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Report
(3 results)
Research Products
(30 results)
