Die Synthese von 2<i>H</i>-Thiopyranen aus β-Thioxoaldehyden
作者:D. Greif、M. Pulst、M. Weißenfels
DOI:10.1055/s-1987-33432
日期:——
The Synthesis of 2H-Thiopyranes from ß-Thioxoaldehydes [4+2]-Cycloaddition reactions between enaminothioketones and activated alkenes, which are described by Quiniou et al.,1-4 usually require relatively harsh reaction conditions, and produce the title compounds only in moderate yields. Much better results can be achieved by a new synthesis of 3-acyl-2H-thiopyranes starting with dicyclohexylammonium salts of monothio-ß-dicarbonyl compounds and unsaturated aldehydes or ketones. The mechanism of this new reaction is characterized by Michael addition followed by an aldol reaction.
从 ß-Thioxoaldehydes 合成 2H-Thiopyranes [4+2]-Cycloaddition reactions between enaminothioketones and activated alkenes,which are described by Quiniou et al.以单硫代-ß-二羰基化合物的二环己基铵盐和不饱和醛或酮为起点,合成 3-acyl-2H-thiopyranes 的新方法可以获得更好的结果。这种新反应的机理是先发生迈克尔加成反应,然后发生醛醇反应。
Modular Synthesis of Fluorinated 2<i>H</i>-Thiophenes via [4+1] Cyclization of Enaminothiones
An efficient and straightforward synthetic method for constructing trifluoromethyl 2H-thiophenes through [4 + 1] cycloaddition of enaminothiones with trifluoromethyl N-tosylhydrazones has been disclosed. The cycloaddition platforms were found to be compatible with a broad substrate scope and to show high regio- and stereo-selectivities under very mild reaction conditions such as room temperature, neutral
Borohydride and cyanoborohydride reduction of thioimonium salts. A convenient route for transformation of amides to amines
作者:Richard J. Sundberg、Claudia Powers Walters、Jonathan D. Bloom
DOI:10.1021/jo00331a032
日期:1981.8
Synthesen auf der Basis von 2-Oxoglutars�ure. IV. Regioselektive Synthese substituierter 2-(2-Methoxycarbonyl-2H-thiopyran-3-yl)glyoxyls�uremethylester