Regioselective Synthesis of Dibenzo[ <i>b</i> , <i>f</i> ]azepin-1-ones via Silver-Catalyzed 7 <i>-</i> endo-dig Cyclization of Alkynyl-Containing Enaminones

Regioselective synthesis of multisubstituted dibenzo[<i>b</i>,<i>f</i>]azepin-1-ones is achieved though CF₃CO₂Ag-catalyzed 7-endo-dig cyclization of terminal alkynes or unactivated internal ones using air as a "green" oxidant. The 100% atom-economical transformation allows the construction of a series of structurally diverse 2,3,4,5-tetrahydro-1<i>H</i>-dibenzo[<i>b</i>,<i>f</i>]azepin-1-ones with 52-89% yields, featuring excellent functional group tolerance and straightforward separation and purification pathways. Also to note, control experiments were conducted to gain crucial insights into the single electron transfer process, where silver(I) functions as the catalyst and molecular oxygen (O₂) serves as the benign terminal oxidant.