Main observation and conclusion
A facile and efficient strategy for the synthesis of 5‐aryl‐2‐(quinolin‐2‐yl)oxazoles via rhodium‐catalyzed formal [3+2] cyclization of 4‐aryl‐1‐tosyl‐1H‐1,2,3‐triazoles with quinoline‐2‐carbaldehydes has been described. The protocol employs mild conditions and offers good yields of diverse 2,5‐aryloxazole derivatives with a broad reaction scope. It is amenable to gram‐scale synthesis and easily transformation. Moreover, this 5‐aryl‐2‐(quinolin‐2‐yl)oxazole skeleton is indeed a new fluorophore and its applications in metal ions probes are also investigated and showed fluorescent responses to mercury ion.