Regioselective Synthesis of 2H-Indazoles Using a Mild, One-Pot Condensation-Cadogan Reductive Cyclization
Regioselective Synthesis of 2H-Indazoles Using a Mild, One-Pot Condensation-Cadogan Reductive Cyclization
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DOI：
10.1021/ol5012423
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发表时间：
2014-06-06
期刊：
影响因子：
5.2
通讯作者：
Aspnes, Gary E.
中科院分区：
文献类型：
--
作者：
Genung, Nathan E.;Wei, Liuqing;Aspnes, Gary E.
报道了一种操作简单、高效的2 H-吲唑的一锅法合成方法。缩合反应生成的邻亚氨基硝基苯底物在三正丁基膦的催化下进行还原环化反应，在温和的反应条件下得到取代的2 H-吲唑。各种电子不同的邻硝基苯甲醛和苯胺进行了检查。为了进一步扩大转化的范围，在优化的反应条件下，脂肪胺也被用来选择性地形成N2-烷基吲唑。
An operationally simple and efficient one-pot synthesis of 2H-indazoles from commercially available reagents is reported. Ortho-imino-nitrobenzene substrates, generated via condensation, undergo reductive cyclization promoted by tri-n-butylphosophine to afford substituted 2H-indazoles under mild reaction conditions. A variety of electronically diverse ortho-nitrobenzaldehydes and anilines were examined. To further extend the scope of the transformation, aliphatic amines were also employed to form N2-alkyl indazoles selectively under the optimized reaction conditions.