Regiodivergent Cu-Promoted, AcOH-Switchable Distal Versus Proximal Direct Cyanation of 1-Aryl-1-indazoles and 2-Aryl-2-indazoles via Aerobic Oxidative C-H Bond Activation.

A copper-promoted regiodivergent, AcOH-switchable, distal and proximal direct cyanation of -aryl-(1/2)-indazoles via aerobic oxidative C(sp)-H bond activation has been developed. The inclusion or exclusion of AcOH as an additive is the foremost cause for the positional switch in the C-CN bond formation method that results in (C-2')-cyanated 2-aryl-2-indazoles , (C-2')-cyanated 1-aryl-1-indazoles [distal], or C-3 cyanated 2-aryl-2-indazoles [proximal] products in good to excellent yields and showed various functional group tolerance. The cyanide (CN) ion surrogate was generated via the unification of dimethylformamide and ammonium iodide (NHI). The utilization of molecular oxygen (aerobic oxidative strategy) as a clean and safe oxidant is liable for generous value addition. The further pertinence of the developed protocol has been demonstrated by transforming the synthesized cyanated product into numerous other functional groups, which will, undoubtedly, accomplish utilization in the synthetic area of biologically important compounds and medicinal chemistry.