Synthesis of 2,4,5-Trisubstituted Oxazoles from Copper-Mediated Benzylic sp C-H Aerobic Oxidative Annulation of Ketones and Amines via a Cascade Reaction.

The functionalization of sp carbons is deemed challenging in synthetic organic chemistry yet has tremendous potential in producing potent organic compounds. A facile synthesis of 2,4,5-trisubstituted oxazoles through an oxidative, copper-catalyzed, and solvent-free annulation is described. Various arylated oxazoles were efficaciously synthesized at a mild temperature from readily available substrates under a molecular oxygen atmosphere.