Fluorocyclization of N-Propargyl Carboxamides by λ3-Iodane Catalysts with Coordinating Substituents

Aiming at the enhanced catalytic activity of fluoro-.3-iodane generated from iodoarene precatalyst with Selectfluor and HF center dot pyridine, this study focused on the.3-iodanes bearing coordinating substituents. Compared to 4-iodoanisole as a precatalyst of our previous method, N-methyl-2-iodobenzamide or 2-iodobenzamide worked well in the fluorocyclization of N-propargyl carboxamides to oxazoles. Control experiments suggest the equilibrium mixture of iodane-amine complexes and cyclic iodane fluorides would be involved in the present catalysis.