Collect. Czech. Chem. Commun. 2009, 74, 957-972
Published online 2009-06-18 10:32:42

Facile and efficient synthesis of indazole derivatives by 1,3-cycloaddition of arynes with diazo compounds and azomethine imides

Tienan Jin*, Fan Yang and Yoshinori Yamamoto*

Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan


N-Unsubstituted indazoles 3 and 1-arylindazoles 4 are readily available in good to high yields through [3+2] cycloaddition of 2-(trimethylsilyl)aryl triflates 1 and diazo compounds in the presence of KF or CsF under mild reaction conditions. Furthermore, we found that azomethine imides also underwent cycloaddition reaction with 2-(trimethylsilyl)phenyl triflates (1a) in the presence of KF to afford indazolone derivatives 6 in moderate yields.

Keywords: [3+2] Cycloaddition; 1,3-Dipolar cycloaddition; Arynes; Diazo compounds; Azomethine imides; Indazoles.

References: 56 live references.