Synthesis of 3-Indazolecarboxylic Esters and Amides via Pd-Catalyzed Carbonylation of 3-Iodoindazoles

A straightforward and effective procedure for the preparation of 1H-indazole-3-carboxylic acid esters and amides was developed. A series of functionalized 3-iodoindazoles were subjected to Pd-catalyzed carbonylations in the presence of methanol or amines, yielding the title compounds in moderate to good yield. For the majority of examples, the reaction proceeded cleanly under mild conditions, which were readily tolerated by a diverse range of functional groups that allow further synthetic transformations.