Stereoselective synthesis of (+/-)-alpha-kainic acid using free radical key reactions

被引:48
作者
Bachi, MD
BarNer, N
Melman, A
机构
[1] Department of Organic Chemistry, Weizmann Institute of Science
关键词
D O I
10.1021/jo9607875
中图分类号
O62 [有机化学];
学科分类号
070303 ; 081704 ;
摘要
Thiol-mediated free radical isomerization of a deliberately substituted but-3-enyl isocyanide 12a, and n-Bu(3)SnH/AIBN-mediated free radical cyclization of a deliberately substituted but-3-enyl isothiocyanate 22, afforded, respectively, the (ethylthio)pyproline 13a and the thiopyroglutamates 5 and 23. Reduction, protection, and deprotection of these heterocyclic compounds afforded proline derivatives 6 and 25 which contain all the structural elements of cr-kainic acid (1) except the C-2 acetic acid moiety. These intermediates were stereospecifically convert-ed into (+/-)-alpha-kainic acid using a new method of temporary sulfur connection. Accordingly, CH(2)CO(9)Me is linked to the chiral isopropenyl anchor and then intramolecularly connected to the pyrrolidine ring and eventually disconnected from its anchor by a sequential reductive double elimination process in which the isopropenyl double bond is restored.
引用
收藏
页码:7116 / 7124
页数:9
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