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A rhodium-catalyzed intermolecular coupling between arylnitrones and diazo compounds by C-H activation/[4 + 1] annulation with a C(N)-C(acyl) bond cleavage is reported, and 2,3-disubstituted NH indoles are directly synthesized in up to a 94% yield. A variety of functional groups are applicable to this reaction to give the corresponding products with high selectivity. Compared to other previously reported Rh(III)-catalyzed synthesis of homologous series, this method is simpler, more general, and more efficient.

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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