| Project/Area Number |
13650901
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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 |
有機工業化学
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| Research Institution | Ochanomizu University |
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Principal Investigator |
YAMADA Shinji OCHANOMIZU UNIVERSITY, Faculty of Science, Professor, 理学部, 教授 (30183122)
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| Project Period (FY) |
2001 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2003: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2002: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2001: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Keywords | cation-π interaction / asymmetric addition / 1,4-dihydropyridine / face-selective addition / intermolecular interaction / nicotinic amide / X-ray structures / pyridinium salt / meroquinen / ピペリジン誘導体 / 立体選択的反応 / 求核付加反心 / オキサゾリジン / CDスペクトル / カチオンーπ相互作用 / 1, 4-ジヒドロピリジン / 求核付加反応 |
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| Research Abstract |
Chiral 1,4-dihydropyridines are continue to be of great interest in relation with calcium agonists, NADH models, and intermediates for alkaloid syntheses, the stereoselective synthesis of these compounds has attracted the attention of researchers. Here we report a new synthetic method of chiral 1,4-dihydropyridines by way of a face-selective addition to a cation-π complex.
Our strategy of a nicotinic amide derivative into a pyridinium salt gives rise to an attractive force between the two entities to form a cation-π complex ; (b) The selective shielding of one side of the pyridinium face by the phenyl ring enables nucleophiles to attack the complex only from the non-shielded side, which will result in 1,4-dihydropyridine stereoselectively.
The reaction of nicotinic amide derivatives 1a (R=benzyl) and 1b (R=phenyl) with ketene silyl acetals in presence of methyl chloroformate gave corresponding 1,2-dihydroyridines 2a (99%de) and 2b (12%de), respectively. Significant difference in the stereoselectivities would be attributable to the geometrical differences between the intermediary pyridinium salts ; the benzyl group much more effectively shields one side of the pyridinium face than the phenyl group.
^1H NMR studies and X-ray crystallographic analysis clarified the existence of a cation-π interaction during the reactions.
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