Intramolecular Thia-anti-Michael Addition of a Sulfur Anion to Enones: A Regiospecific Approach to Multisubstituted Thiophene Derivatives
作者:Yan Li、Fushun Liang、Xihe Bi、Qun Liu
DOI:10.1021/jo0611420
日期:2006.10.1
The intramolecular thia-anti-Michael addition starting from readily available α-alkenoyl-α‘-carbamoyl ketene-(S,S)-acetals 1 containing a 1,3-dithiolane moiety was developed. In particular, in the presence of aliphatic primary amines, a series of tetrasubstituted thiophene derivatives, 2-(alkylamino)-5-alkyl-4-hydroxythiophene-3-carboxamides 2, were synthesized via tandem fragmentation, substitution
从容易获得的含有1,3-二硫杂环戊烷部分的α-链烯酰基-α'-氨基甲酰基酮基-(S,S)-乙缩醛1开始,开发了分子内硫-抗-迈克尔加成。特别地,在脂肪族伯胺的存在下,通过串联断裂,取代和分子内硫-抗合成了一系列四取代的噻吩衍生物2-(烷基氨基)-5-烷基-4-羟基噻吩-3-羧酰胺2。-1的Michael加成反应,其中胺起碱和亲核试剂的双重作用。作为关键步骤,分子内硫-抗-迈克尔加成反应以区域特异性方式进行,并显示了烯酮1的β-取代基的一般范围。提出了形成多取代噻吩的可能机理。通过这项研究,创造了一种新的有效途径来制备各种四取代的噻吩衍生物。