Preparation of 3,4,5-Trisubstituted Oxazolones by Pd-Catalyzed Coupling of <i>N</i>‑Alkynyl <i>tert</i>-Butyloxycarbamates with Aryl Halides and Related Electrophiles

A novel palladium-catalyzed approach for the assembly of 3,4,5-trisubstituted oxazolones has been achieved by the coupling of N-alkynyl tert-butyloxycarbamates with aryl halides and related electrophiles, which involves an oxidative addition followed by oxypalladation/reductive elimination. The reaction provides a convenient access to diversely substituted oxazolones in satisfactory yields and shows good functional group compatibility.