Metal-Free Trifluoromethylation of Indazoles.

A simple and efficient tert-butyl hydroperoxide-mediated direct trifluoromethylation of indazoles using sodium trifluoromethanesulfinate has been developed under metal-free conditions. A library of trifluoromethylated products with broad functionalities has been synthesized with moderate to good yields. A radical mechanistic pathway has been proposed for the present protocol.