A rhodium-catalyzed regioselective C-H olefination of indazole is described. This protocol relies on the use of an efficient and removable N,N-diisopropylcarbamoyl directing group, which offers facile access to C7-olefinated indazoles with high regioselectivity, ample substrate scope and broad functional group tolerance.

We present a novel, efficient, and regioselective method for the rhodium-catalyzed direct C-H ortho-halogenation of anilines that involves a removable N-nitroso directing group. This method featured mild reaction conditions, wide substrate scope, good functional group tolerance and satisfactory yields. To maintain the high ortho-regioselectivity and conversion, increasing the steric hindrance of the solvent was critical. Preliminary mechanistic studies suggest that C-H activation may be involved in the rate-determining step.

An efficient rhodium-catalyzed direct C-H amidation of N-nitrosoanilines with 1,4,2-dioxazol-5-ones as amidating agents has been developed. This method featured mild reaction conditions, a wide substrate scope and satisfactory yields. Besides, the amidated products could be readily converted to pharmaceutically valuable 1,2-disubstituted benzimidazoles via an HCl-mediated deprotection/cyclization process in one pot.

A CuCl catalyzed C-N cross-coupling reaction using commercially available 1H-indazoles with diaryliodonium salts is described. The methodology features ample structural versatility, affording 2-substituted-2H-indazole in good yields and complete N(2)-regiocontrol. Furthermore, the utility of the reaction was demonstrated in the synthesis of a known estrogen receptor β agonist. Mechanistic studies using density functional theory calculations suggested that the complete regioselectivity can be attributed to the only weak base TfO in our system which could not deprotonate indazoles, and the catalyst oxidation process would be the rate-determining step.

A rhodium‐catalyzed regioselective C7‐functionalization of indazoles without any substituent at the C3‐position has been achieved. The removable N,N‐diisopropylcarbamoyl directing group proved crucial for both C7‐regioselecivity and conversion. Good to excellent yields were observed with acrylates, vinyl phenyl sulfones, and electron‐neutral olefins (styrenes). The reaction could conveniently be scaled up to a gram scale, thus highlighting the robustness and practicality of this transformation. More information can be found in the Communication by Xianhua Pan, Lanting Xu et al. on page 289 in Issue 3, 2017 (DOI: 10.1002/asia.201601456).