A transition‐metal‐free oxidativeCN coupling method has been developed for the synthesis of 1H‐azaindazoles and 1H‐indazoles from easily accessible hydrazones. The procedure uses TEMPO, a basic additive, and dioxygen gas as the terminal oxidant. This reaction demonstrates better reactivity, functional group tolerance, and broader scope than comparable metal catalyzed reactions.
An efficient transition-metal-free synthesis of 1H-indazoles from arylhydrazones with montmorillonite K-10 under O2 atmosphere
作者:Jin Yu、Jin Woo Lim、Su Yeon Kim、Jimin Kim、Jae Nyoung Kim
DOI:10.1016/j.tetlet.2015.01.183
日期:2015.3
An efficient transition-metal-free synthetic method of 1H-indazoles has been developed. The reaction of arylhydrazones in the presence of montmorillonite K-10 in 1,2-dichlorobenzene at 130 degrees C afforded 1Hindazoles in good yields most likely via a sequential intramolecular nucleophilic cyclization and an aerobic oxidation pathway. (C) 2015 Elsevier Ltd. All rights reserved.