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An Efficient, Facile, and General Synthesis of 1 H ‐Indazoles by 1,3‐Dipolar Cycloaddition of Arynes with Diazomethane Derivatives

2007; Wiley; Volume: 46; Issue: 18 Linguagem: Inglês

10.1002/anie.200700101

1521-3773

Tienan Jin, Yoshinori Yamamoto,

Chemical synthesis and alkaloids

Take your pick: Both N-unsubstituted and 1-aryl 1H-indazoles are available in good to high yields through the [3+2] cycloaddition of benzynes derived from o-silylaryl triflates with diazomethane derivatives (see scheme). In the presence of KF/[18]crown-6, the N-unsubstituted 1H-indazole is formed, whereas the 1-arylated product is obtained regioselectively with CsF and an excess of the triflate. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2007/z700101_s.pdf or from the author. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.