1997 Fiscal Year Final Research Report Summary
Catalytic Asymmetric Synthesis of Bioactive Molecules
| Project/Area Number |
07557139
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Chemical pharmacy
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| Research Institution | KYOTO UNIVERSITY (1996-1997)
Osaka University (1995) |
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Principal Investigator |
TOMIOKA Kiyoshi KYOTO UNIVERSITY Graduate School of Phamaceutical Sciences, Professor, 薬学研究科, 教授 (50114575)
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| Co-Investigator(Kenkyū-buntansha) |
INOUE Isao Tanabe Seiyaku Co., Ltd., Investigator, 研究員
NAGAOKA Yasuo KYOTO UNIVERSITY Graduate School of Phamaceutical Sciences, Instructor, 薬学研究科, 助手 (90243039)
IIDA Akira KYOTO UNIVERSITY Graduate School of Phamaceutical Sciences, Assiociate Professor, 薬学研究科, 助教授 (40202816)
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| Project Period (FY) |
1995 – 1997
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| Keywords | chiral ligand / lithiumthiolate / conjugate addition / lithium enolate / catalytic reaction / asymmetric reaction / 2-trimethylsilythiphenol / conjugate addition |
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| Research Abstract |
As our continuing studies toward enantioselective reactions of organolithiums based on an external chiral ligand, we have developed the catalytic asymmetric addition of thiophenol to enoates using lithium thiophenolate as a catalytic nucleophile which has higher reactivity than thiophenol activated by amine. The 2-substituent of thiophenol exerts profound effects on reactivity and enantioselectivity in the asymmetric addition reaction with enoates catalyzed by lithium thiophenolate and a chiral ligand. The bulky substituent gave the higher reactivity and enantioselectivity. The asymmetric reaction of 2-trimethylsilylthiophenol with methyl enoates was catalyzed by the combination of 0.08 eq of lithium 2-trimethylsilylthiophenolate and 0.1 eq of the chiral ligand, (1R,2R)-1-dimethylamino-2-(2-methoxyphenoxy)-1,2-diphenylethane, in toluene-hexane (1 : 1) to afford the corresponding methyl 3-(2-trimethylsilylphenylthio) carboxylates in excellently high ees. The chiral ligand was recovered quantitatively for reuse without racemization. The 2-trimethylsilyl group was protodesilylated by treatment with triflic acid to give the corresponding 3-phenylthiocarboxylates in excellently high yield without racemization. The kinetic control is operative in the asymmetric addition reaction.
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Research Products
(12 results)
