Synthesis of 2 H-Indazoles by the [3+ 2] Cycloaddition of Arynes and Sydnones

C Wu, Y Fang, RC Larock, F Shi

Index: Wu, Chunrui; Fang, Yuesi; Larock, Richard C.; Shi, Feng Organic Letters, 2010 , vol. 12, # 10 p. 2234 - 2237

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Citation Number: 95

Abstract

Compared with 1H-indazoles, 2H-indazoles have been much less studied in part due to the difficulty in their preparation. Most existing methods give mixtures of 1H- and 2H-indazoles,(4) and the selective preparation of 2H-indazoles remains challenging. Although recently several promising synthetic routes to 2H-indazoles have been reported,(5) the demand for new, efficient, and selective methods to prepare 2H-indazoles using readily available starting materials under mild ...