Synthetic Study of a Styrylpyrone Natural Product by Asymmetric Reactions
| Autor: | Yu-Jin Chen, 陳昱瑾 |
|---|---|
| Rok vydání: | 2008 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 97 Goniodiol is a natural product isolated from the leaves of Goniothalamus sesquipedalis(Annonaceae). It is one of styryllactones with a 5,6-dihydro-2-pyrone structure. It exhibits the anti-tumor activity and insect disinfestation, and its anti-tumor activity is particularly important. In this thesis, we propose a synthetic study of a styrylpyrone natural product in the asymmetric reactions. In the synthesis of gonidiol, cyclopentene was chosen as the starting material. After ozonolysis and treatment of Et3N and Ac2O, methyl 5- oxopentanoate was obtained. The Wittig reaction of the aldehydc group of methyl5-oxopent-anoate with a triphenylphosphorane gave methyl (E)-7-oxo-7-phenylhept-5-enoate, which reacted with (R)-2-methyl-CBS- oxazaborolidine and BH3‧SMe2 to provide a secondary alcohol. The alcohol was treated with TBDMSCl and imidazole in DMF to give a TBDMS-protectded silyl ether. The double bond was oxidized by Sharpless asymmetric dihydroxylation to give a diol, and its intramolecular esterification by Amberlyst-15 afforded methyl (5R,6S,7R)-7- (tert-butyldimethylsilyloxy)-5,6-dihydroxy-7-phenylheptanoate. It was treated with TBDMSCl to protect the diol, and then reacted with PhSeBr followed by oxidation with 30% H2O2 to furnish a dihydropyranone. Finally, (+)-goniodiol was obtained after the protective groups were removed by n-Bu4NF. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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