Direct C-3-Arylations of 1H-Indazoles

The first example of intermolecular CH arylation of substituted 1H-indazoles is reported. Various 1-substituted indazoles were used as starting materials, and (hetero)aryl bromides and iodides were investigated as coupling partners. Different reaction conditions were investigated. The best results were obtained using Pd(OAc)2 as catalyst, 1,10-phenanthroline as ligand, K2CO3 as base, and DMA as solvent. The crucial role of the ligand on the CH arylation of substituted 1H-indazoles is highlighted.