A facile synthesis of 2,5-disubstituted oxazoles via a copper-catalyzed cascade reaction of alkenes with azides

A novel and efficient approach to the synthesis of 2,5-disubstituted oxazoles is developed via a 1,3-dipolar cycloaddition/ring cleavage/1,2-H migration/denitrogenation/copper-catalyzed aerobic oxidative dehydrogenative cyclization cascade. The desired products can be obtained from readily available aromatic terminal alkenes and azides employing air as the oxidant under mild conditions, and it offers an attractive alternative method for the synthesis of oxazole derivatives.