Diastereoselective radical cascade cyclization to access indole-fused diazepine derivatives

The synthesis of polycyclic indoles is significant in organic chemistry, due to such heterocyclic frameworks being present in numerous bioactive pharmaceuticals and natural alkaloids. Herein, we provide an efficient radical cascade cyclization strategy to generate indole-fused diazepine derivatives using phosphoryl or sulfonyl radicals with <i>N</i>-(2-(1<i>H</i>-indol-1-yl)phenyl)-<i>N</i>-methylmethacrylamides. The merits of this synthesis are attributed to its accessible starting materials, broad substrate compatibility and excellent diastereoselectivity.