Synthesis of Indoline Fused 1,3‐Diazepines via C−H Activation‐Initiated Cascade Reactions of Indolin‐1‐yl(aryl)methanimines with Pyridotriazoles as Safe Carbene Precursors

The search and use of diazo surrogates as safer carbene precursors constitute an important task among the synthetic community. Presented herein is a concise and robust synthesis of indoline fused 1,3‐diazepines via the cascade reactions of indolin‐1‐yl(aryl)methanimines with pyridotriazoles as safe alternative carbene precursors. With this method, 43 diazepine derivatives were prepared in up to 80% yield. Preliminary mechanism studies showed that the formation of product involves a cascade process including C−H bond metallation, carbene formation, migratory insertion and intramolecular condensation. With merits such as safe and easy‐to‐handle carbene precursor, good compatibility with diverse functional groups, high atom‐economy and ready scalability, this synthetic strategy has the potential to be applied in related areas.