Synthesis of 1-aryl-1 H-indazoles via palladium-catalyzed intramolecular amination of aryl halides

…, AS Khartulyari, AZ Voskoboynikov

Index: Lebedev, Artyom Y.; Khartulyari, Anton S.; Voskoboynikov, Alexander Z. Journal of Organic Chemistry, 2005 , vol. 70, # 2 p. 596 - 602

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Citation Number: 85

Abstract

Palladium-catalyzed cyclization of arylhydrazones of 2-bromoaldehydes and 2- bromoacetophenones to give 1-aryl-1 H-indazoles has been studied in detail. The cyclization of arylhydrazone of 2-bromobenzaldehydes can be performed with good to high yields using Pd (dba) 2 and chelating phosphines, of which the most effective are rac- BINAP, DPEphos, and dppf, in the presence of Cs2CO3 or K3PO4 as a base. Electron-rich ...