Synthesis of Bicyclic Piperidines and Alkaloids by Intramolecular Aza-Michael Reactions
| Autor: | Jhih-Liang Huang, 黃智莨 |
|---|---|
| Rok vydání: | 2013 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 101 This thesis used the cross metathesis of C ‐ 6 substituted 4-phenylthio-5,6-dihydro-2-pyridones (3) with methyl acrylate to synthesize compounds 51. Further treatment with Bu3SnH/AIBN led to the detosylation compounds 52. The bicyclic piperidines 53 could be obtained by intramolecular aza-Michael reaction of compounds 52 under basic conditions. We also studied the diastereoselectivity of the cyclization reaction. Reduction of the ester group of compound 53a (cis/trans 1:1) by treatment with LiAlH4 at low temperature afforded compounds cis-63 and trans-63. Bromination of compound cis-63, followed by debromination reaction gave compound cis-65. Reaction of compound cis-65 with Raney nickel both cleaved the C－S bond and reduced the C=C bond to give compound cis-66. Further treatment of compound cis-66 with methylmagnesium bromide, followed by acidification with acetic acid, and reduction with sodium borohydride accomplished the synthesis of (±)-indolizidine 167E. We also applied this strategy to synthesize compound 71 from ester 53b through alcohol 68. Compound 71 was subsequently converted to compound 75, which was treated with Raney nickel to afford compound 78, the proposed structure for quinolizidine 195C. But the spectral data of compound 78 differed significantly from those reported in the literature for quinolizidine 195C. Thus the true structure of quinolizidine 195C remains uncertain. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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