ChemInform Abstract: A General Synthesis of Diversely Substituted Indazoles and Hetero-Aromatic Derivatives from O-Halo-(het)arylaldehydes or -phenones

A set of variously substituted indazoles and hetero-aromatic derivatives were synthesized from o -halo-(het)arylaldehydes using a palladium catalyzed amination followed by cyclization. Starting from phenones, this process was extended to give 3-substituted indazoles. Moreover, N -1-substituted-indazoles can be reached by this strategy using an optional selective N-1-alkylation step during the process. This methodology offers a general and easy route for the synthesis of regioselectively substituted indazoles.