Efficient access to 1H-indazoles via copper-catalyzed cross-coupling/cyclization of 2-bromoaryl oxime acetates and amines

Abstract

We describe a novel and useful method to provide 1H-indazoles via copper-catalyzed tandem reaction which is triggered by an Ullmann-type reaction and followed by N–N bond formation. Arylamines, alkylamines and sulfonamides could smoothly couple with 2-bromoaryl oxime acetates and various 1H-indazoles were formed in good to excellent yields under mild reaction conditions.