Transition metal-free cycloisomerization of propargylic amides to oxazoles in hexafluoroisopropanol (HFIP)

Abstract

A transition metal-free method for the cycloisomerization of propargylic amides to oxazoles was developed. The reaction utilizes in situ generated hydrogen chloride in hexafluoroisopropanol (HFIP). With the aid of Design of Experiments optimization a wide range of substrates was transformed into the desired oxazoles. The method allows product formation without side reactions eliminating the need for extensive work-up and purification.