"On Water" Palladium Catalyzed Direct Arylation of 1Indazole and 1-7-Azaindazole.

The C3 direct arylation of 1-indazole and 1-7-azaindazole has been a significant challenge due to the lack of the reactivity at this position. In this paper, we describe a mild and an efficient synthesis of new series of C3-aryled 1-indazoles and C3-aryled 1-7-azaindazoles via a C3 direct arylation using water as solvent. On water, PPh was effective as a ligand along with a lower charge of the catalyst Pd(OAc) (5 mol%) at 100 °C, leading to C3-aryled 1-indazoles or C3-aryled 1-7-azaindazoles in moderate to good yields.