Tosylhydrazide-Induced\n1,6-Enyne Radical Cyclization\nunder Copper Catalysis: Access to 3,4-Dihydronaphthalen-1(2<i>H</i>)‑one Derivatives

We describe an approach to access 4-aroyl-3-aryl-3,4-dihydronaphthalen-1(2<i>H</i>)-one derivatives in 41–79% yields through the Cu-catalyzed\nradical cyclization/desulfonylation of 1,6-enynes with tosylhydrazide\nunder air conditions. This alternative desulfonylation strategy combines\nmild conditions, external oxidant-free processes, and sustainability,\ncontributing to more environmentally friendly organic synthesis. The\nmechanistic studies showed that the CuCl/O<sub>2</sub> combination\nserves as the source of the oxygen atom needed to form the CO\nbond. The existence of tosylhydrazide is crucial for this conversion.