Synthesis of Tetrahydro[1,3,4]triazepines via Redox-Neutral α‑C(sp3)–H Amination of Cyclic Amines

A Brønsted acid-catalyzed α-C­(sp3)–H amination of cyclic amines using hydrazines as coupling partners has been reported. This methodology provides a unique protocol to the one-step assembly of tetrahydro­[1,3,4]­triazepines via [1,5]-hydride transfer-initiated C­(sp3)–H amination. This reaction features mild conditions, good yields, and high atom economy.