Remarkably Efficient Synthesis of 2<i>H</i>-Indazole 1-Oxides and 2<i>H</i>-Indazoles via Tandem Carbon−Carbon Followed by Nitrogen−Nitrogen Bond Formation
followed by nitrogen-nitrogen bond formations quantitatively converted N-alkyl-2-nitro-N-(2-oxo-2-aryl-ethyl)-benzenesulfonamides to 2H-indazoles 1-oxides under mild conditions. Triphenylphosphine or mesylchloride/triethylamine-mediated deoxygenation afforded 2H-indazoles.