| Project/Area Number |
10650849
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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 |
OSHIMA Takumi Graduate School of Engineering, Department of Materials Chemistry, Osaka University, Professor, 大学院・工学研究科, 教授 (40107082)
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| Project Period (FY) |
1998 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2001: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 2000: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1999: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1998: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Keywords | [2+2] photocycloaddition / Homoquinone / Diels-Alder Reaction / Cation Recognition / Regioselectivity / Endo-selectivity / Kinetics / Substituent Effects / ナフトキノン / ジアゾアルカン / 1, 3-双極子付加 / 光分解 / 熱分解 / 6π電子環化 / カルベン / ピリドノクラウンエーテル / 光誘起電子移動 / 光付加反応 / プロトン移動 / 骨格転位反応 / ルイス酸 / クラウン化ベンゾフェノン / 光水素引抜反応 / 1,3-双極子付加反応 / 反応速度 / 反応制御 / キノン / 電子移動 / 光水素引抜 / ディールス・アルダー反応 / クラウンエーテル / カチオン包摂 |
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| Research Abstract |
[2+2] photocycloaddition: Irradiation of various meto- and para-substituted homobenzoquinones with ethyl vinyl ethers gave the [2+2] photoadducts regio- and endo-selectively. The adducts have an antiform built by the addition of ethyl vinyl ethers from the less hindered side of homobenzoquinones. All of the CH_3, Cl, Br, and CH_3O substituents at the reacting C = C double bond afforded head-to-head addition predominantly. In the case of CH_3, Cl, and Br, the ethoxy group was -oriented in the endoposition, while the CH_3O substituent led to a 1/5 mixture with the exo-isomer. It was also found that the Br-substituted [2+2] adducts undergo a facile skeletal rearrangement, being converted into dihydro-obenzoquinone methide for para-substituent and dihydro-o-benzofuran derivatives for meta-substitution, probably under the influence of the in sit generated HBr.
Diels-Alder reactions of quinocrown ethers: 15-21-membered auinocrown ethers 1a-c and 18-membered quinobenzocrown ether 1d with cyclo
… More
pentadiene were catalyzed by the addition of alkali, alkaline earth metal and ammonium perchlorates, and scandium trifluoromethane-sulfonate. The alkali metal ions brought about a fairly selective rate-acceleration for each crown ether due to the size-fitted ion-in-the-hole complexation. However, such a hole-size-selectivity was not observed for the reactions catalyzed by divalent alkalie earth (Mg^<2+> to Ba^<2+>) and trivalent Sc^<3+> ions. The wrapping complexation played a significant role in rate-acceleration in such a way that the smallest Mg^<2+> caused 160 times rate-enhancement for the most flexible 1c and the Sc^<3+> performed maximal 3700 times rate-increment for the 18-membered quinobenzocrown 1d. These effects of cation recognition were rationalized by the reduction of LUMO energy that is favored by the orbital interaction with the HOMO of cyclopentadiene. The magnitude of rate-enhancement was expained in terms of the cation binding affinity and coordination geometry of quinocrown ethers as well as the valence of cations. Less
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