In contrast to chemical reactions of troponoid ([7]annulenone) compounds reported so far, the tosylate of tropone oxime reveals a novel ring opening reaction under mild conditions at the temperature between -20 and 0 degrees C. This nucleophilic reaction affords exclusively and stereoselectively a variety of 6-substituted (Z,Z,Z)-1,3,5-hexatrienecarbonitriles, as the sole products in high yields. The opening reaction is caused by the intramolecular (HOMO --> sigma*) charge transfer in the Meisenheimer tetrahedral intermediate.