“…Methods for direct construction of oxazole ring range over a variety of reactions and starting materials. Some of the oldest and most widely used methods for substituted oxazoles include cyclodehydration of α-acylaminocarbonyl compounds (Robinson−Gabriel synthesis), , the Cornforth and Cornforth method improved by Yokoyama, the biomimetic dehydrative cyclization of β-hydroxy amides to oxazolines and their oxidative dehydrogenation, − the Hantsch-type reaction of α-halo/acyloxy carbonyl compounds with amides, the rhodium-catalyzed decomposition of α-diazocarbonyl compounds in the presence of nitriles, and the photolysis/pyrolysis of α-acylisoxazolones . However, these methods genuinely lack universality and suffer from one or more drawbacks such as modest to poor yields, harsh reaction conditions, longer reaction time, and reactive starting materials with limited stability, which make them incompatible for the range of tolerated functional groups in the target oxazole.…”