| Project/Area Number |
09555286
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Synthetic chemistry
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| Research Institution | Okayama University |
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Principal Investigator |
SAITO Seiki Okayama University, Faculty of Engineering, Professor, 工学部, 教授 (60033239)
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| Co-Investigator(Kenkyū-buntansha) |
ISHIKAWA Teruhiko Okayama University, Faculty of Engineering, Instructor, 工学部, 助手 (10263617)
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| Project Period (FY) |
1997 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥13,400,000 (Direct Cost: ¥13,400,000)
Fiscal Year 1999: ¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1998: ¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 1997: ¥9,000,000 (Direct Cost: ¥9,000,000)
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| Keywords | Taxol / cyclohexane-1,3-dione / consecutive Michael-Claisen reaction / ビナコール環化 / タキソ-ル / 8員環合成 / 分子内[3+2]環化付加反応 |
|---|
| Research Abstract |
We have revisited the traditional consecutive Michael-Claisen [3 + 3] process (MC-[3+3]) promising for the synthesis of a cyclohexane-1, 3-dione derivatives from non-activated simple ketones and enoates, and evaluated its potential in modern organic synthesis. The reaction conditions employing the ketones (1.2 equiv), enoate (1.0 equiv), and t-BuOK (1.2 equiv) in THF as a solvent at temperature range of 0℃ to 40℃ have been established. Twenty to thirty examples were demonstrated to be effective under such conditions including the synthesis of a taxol A, C-ring synthons available in multi-gram quantities. The reactions exhibited remarkable regioselectivity that the Michael addition proceeded through nucleophilic attack by more hindered site of the ketones without exceptions, which, in turn, means that Claisen condensation resulted in the formation of carbon-carbon bonds between less hindered site of the ketones and acyl carbon of the enoates. In addition, taking advantages of the MC- [3+3] process, a few useful methods for the synthesis of six membered carbocyclic compounds have also been developed. A number of control experiments have been conducted to provide strong supporting information for the mechanism of this MC-[3+3] process.
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