Photo-induced and azide anion-facilitated atom transfer cyclization of <i>N</i> -allyl-2-bromoamides

NaN₃ can facilitate the bromine atom transfer radical cyclization (ATRC) of <i>N</i>-allyl-2-bromoamides under visible light irradiation. The beneficial effect of NaN₃ is attributable to the activating interaction between the azide anion and the C-Br bond in <i>N</i>-allyl-2-bromoamides. The reaction provides a metal-free approach toward γ-lactams.