1995 Fiscal Year Final Research Report Summary
Construction of Asymmetric Space and Catalytic Stereoselection with C_2-Symmetrical Molecules
| Project/Area Number |
06640765
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
物質変換
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| Research Institution | Shizuoka University |
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Principal Investigator |
YODA Hidemi Shizuoka University, Engineering, Associate Professor, 工学部, 助教授 (20201072)
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| Project Period (FY) |
1994 – 1995
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| Keywords | Bisoxazoline / Chiral Ligand / Metal Complex / Amino Acid / Tartaric Acid / C_2-Imide / Nucleophilic Addition / Deoxygenation |
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| Research Abstract |
1. According to my research scheme, asymmetric catalyst with the bisoxazoline ring system could be obtained from the coupling reaction of 2 equiv.of chiral amino alcohols with malononitrile-derived imidate and its activity as a chiral catalyst was investigated based on the alkylation of benzaldehyde with diethylzinc. Consequently, this reaction proceeded in about 40% ee.
2. Consecutive treatment of C_2-symmetrical imides elaborated from L-tartaric acid with Grignard reagent and NaBH_4 afforded separable diastereomixture of chiral amide alcohols in high selectivity. Using these amide alcohols as catalysts, asymmetric alkylation with diethylzinc was investigated and the results are as follows ;
(1) increasing a steric bulkiness of the N-substituent leads to an increase of the enantioselectivity.
(2) maximally the catalyst recycles 18.8 times.
(3) higher selectivity was obtained in the case of the catalyst with (4S)-configuration.
(4) to enhance the selectivity ether is preferable over toluene as a solvent.
Further, cyclic amides derived from D-arabinofuranose were also submitted to the same type of chiral catalytic reactions. It is interesting that no procedure for the asymmetric reactions with diethylzinc employing such as amide alcohols of cyclic amides as chiral catalysts has so far appeared.
3. In addition to these reactions, asymmetric total syntheses of antibiotics, (-)-anisomycin and (+)-preussin were accomplished employing stereoselective nucleophilic addition and asymmetric deoxygenation of the hydroxy lactam intermediate elaborated from the same starting material, arabinofuranose.13EA09 : In summary, two new types of chiral ligands were prepared and investigated based on their catalytic activity and two antibiotic natural products were synthesized.
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