Gold-Catalyzed Radical-Involved Intramolecular Cyclization of Internal N-Propargylamides for the Construction of 5-Oxazole Ketones

An expedient strategy for the synthesis of 5-oxazole ketones was developed via homogeneous gold catalysis with 4-MeO-TEMPO as an oxidant. The desired 5-oxazole ketones were achieved in decent yields with an excellent functional group compatibility under mild conditions. The current protocol also represents the first example for merging a gold catalyst and radical chemistry in one-pot synthesis with internal N-propargylamides.