Preparation of 3,4,5‐Trisubstituted Oxazolones by Pd‐Catalyzed Coupling of N‐Alkynyl tert‐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.