A new efficient palladium (II)-catalyzed [3, 3] aza-Claisen, formal sigmatropic rearrangement of 3-allyloxy-5-aryl-1, 2, 4-oxadiazoles was developed. The mechanism was studied by analyzing the regiochemical and stereochemical course of the reaction. The results obtained indicated the intervention of a cationic pallada-cycle similar to the one postulated for the Cope rearrangement of 1, 5-dienes.