2013年4月
Critical profiles of chiral diether-mediated asymmetric conjugate aminolithiation of enoate with lithium amide as a key to the total synthesis of (-)-kopsinine
TETRAHEDRON
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- 巻
- 69
- 号
- 15
- 開始ページ
- 3264
- 終了ページ
- 3273
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1016/j.tet.2013.02.035
- 出版者・発行元
- PERGAMON-ELSEVIER SCIENCE LTD
Chiral diether-mediated asymmetric aminolithiation of indolylpropenoate with lithium amide in toluene at -78 degrees C for 15 min gave, after aqueous ammonium chloride quench, the corresponding conjugate addition product with 97% ee in 89% yield. If hydrogen chloride in methanol was selected as a quencher, however, aminolithiation at -78 degrees C for 3 h gave the corresponding adduct with 97% ee in 54% yield, along with recovery of the starting enoate in 39% yield. Based on this finding of an incomplete and slow reaction at -78 degrees C, the aminolithiation conditions were optimized to be at -60 degrees C for 15 h and subsequent enolate trap with alkyl halide upon an addition of DMPU afforded the desired aminoalkylation product with 98% ee in 89% yield. Further approach toward total synthesis of (-)-kopsinine was carried out by examining asymmetric aminolithiation with N-hydroxyethylamine equivalent, one-pot piperidine formation, and Claisen condensation. (C) 2013 Elsevier Ltd. All rights reserved.
- リンク情報
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- DOI
- https://doi.org/10.1016/j.tet.2013.02.035
- Web of Science
- https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000316582400018&DestApp=WOS_CPL
- URL
- http://www.scopus.com/inward/record.url?eid=2-s2.0-84875231708&partnerID=MN8TOARS
- URL
- http://orcid.org/0000-0002-9006-8249
- ID情報
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- DOI : 10.1016/j.tet.2013.02.035
- ISSN : 0040-4020
- ORCIDのPut Code : 29040006
- SCOPUS ID : 84875231708
- Web of Science ID : WOS:000316582400018