Single-Step Synthesis of Iodinated Oxazoles from N-Propargyl Amides Mediated by I2/Iodosylbenzene/Trimethylsilyl Trifluoromethanesulfonate Systems.

A combination of I2, iodosylbenzene, and trimethylsilyl trifluoromethanesulfonate (TMSOTf) is effective for single-step synthesis of iodinated oxazoles from N-propargyl amides via the aromatization of the iodocyclized intermediates, which has difficulty proceeding through conventional iodocyclization methods. Compared to the former method consisting of the metal-catalyzed cyclization of N-propargyl amides followed by halogenation of alkylideneoxazolines, the present reaction provides a facile and metal-free procedure.