Functionalization of 2‐Aryl‐2 H ‐1,2,3‐Triazoles by Reaction of Triazole‐ N ‐Oxides With o ‐Silylaryl Triflates: A New Tale From Aryne Chemistry

The first study of the functionalization of 2‐aryl‐2 H ‐1,2,3‐triazole N ‐oxides via aryne chemistry is reported. Under optimized conditions using TBAF in DCM, various N ‐oxides react with arynes generated from o ‐silylaryl triflates to afford 2‐(2‐aryl‐2 H ‐1,2,3‐triazol‐4‐yl)phenols in moderate‐to‐excellent yields (41%–91%). Notably, N ‐oxides bearing a methoxycarbonyl group at the 4‐position undergo a subsequent intramolecular cyclization, yielding 2‐arylchromeno[3,4‐ d ][1,2,3]triazol‐4(2 H )‐ones. The latter compounds exhibit violet‐to‐blue photoluminescence with quantum yields of up to 72% in solution and up to 28% in solid state, depending on the substituent pattern. This work establishes a versatile and straightforward route to both triazolylphenols and fluorescent chromenotriazolones.