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 excellent functional group compatibility under mild conditions. The current protocol also represents the first example for merging gold catalyst and radical chemistry in one-pot synthesis with internal N-propargylamides.