The ring expansion of keto-aziridines to the corresponding 2,5-diaryloxazoles in the presence of iodine in refluxing dimethyl sulfoxide, is described. A plausible mechanism for the synthesis of 2,5-diaryloxazoles is proposed.

C-C Bond Cleavage of Keto-Aziridines; Synthesis of Oxazoles via Regio--Controlled Ring Expansion. -Various 2,5-diaryloxazoles (II) are prepared regioselectively from the trans-aziridines. Independent from the substitution pattern on the phenyl group of the 2-benzoyl substituent, 3-nitrophenyl substituted aziridines (III) do not react to the corresponding oxazole derivatives. Instead, 3-nitrobenzaldehyde (IV) is formed in low yield. -(SAMIMI*, H. A.; ENTEZAMI, S.; J. Chem. Res. 37 (2013) 12, 745-747, http://dx.