A nonmetal-catalyzed oxidative cyclization to achieve 2,5-disubstituted oxazoles from inexpensive and readily available substituted chalcone, (diacetoxyiodo)benzene (PIDA) and ammonium acetate (NH4OAc) at room temperature is described. The reaction forms a variety of 2,5-diaryloxazoles in good to excellent yields with broad substrate scope under mild conditions without the requirement of ligands and additional bases.

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An efficient route for the synthesis of diverse pyridines has been developed through ac opper-catalyzed cyclization of ketoxime carboxylates and N-aryl glycine esters with NÀOa nd CÀNb ond cleavage. In this reaction, avariety of functional groupswere tolerated;thus, providing as imple way to afford polysubstituted pyridines in good yields under mild conditions.

A new method for the synthesis of imidazo[1,5‐α]pyridines, one of the most important N‐heterocyclic compounds due to their wide application, was reported in this study. Specifically, using I2 as a non‐metal catalyst and TBPB as an oxidant can efficiently facilitate the synthesis and avoid the use of a metal catalyst. The reaction between ethyl (E)‐2‐(benzylideneamino)acetate and pyridine represents an unprecedented 1,3‐diolar cycloaddition in highly straightforward process with great value.