Copper(II) Triflate Catalyzed Synthesis of 2,4-Disubstituted Oxazoles from α-Diazoketones

A novel method is devised for the synthesis of 2,4-disubstituted oxazole derivatives via the coupling of α-diazoketones with amides using copper(II) triflate as the catalyst. The synthetic versatility of this approach is exemplified in the synthesis of an analogue of balsoxin.