Visible-Light-Promoted Direct C3-H Cyanomethylation of 2 H -Indazoles.

The efficient visible-light-promoted cyanomethylation of 2 H -indazoles in the presence of Ir(ppy) 3 as the photocatalyst and bromoacetonitrile as the cyanomethyl radical source was achieved under mild conditions, providing a series of C3-cyanomethylated derivatives in good yields.