The mechanism of the thermal rearrangement of 1-aryl-5-allyloxytetrazoles 1 to give 1-aryl-4- allyltetrazolones 2 in very high yield has been investigated through kinetic studies in one polar and one less polar solvent. The results suggest mainly a concerted [3, 3] sigmatropic process, in which a partially positively charged allyl group migrates from oxygen to nitrogen, similar to the polar transition state found in the Claisen rearrangement.
