NEW AROMATIZATIONAL TRANSFORMATIONS OF 4-METHYL-4-TRICHLOROMETHYL-SUBSTITUTED 2,5-CYCLOHEXADIENE TRIPHENYLPHOSPHONIUM AND PYRIDINIUM YLIDES- ABSTRACTION OR 1,6-MIGRATION OF THE CCL3 GROUP

4-Methyl-4-trichloromethylcyclohexadiene triphenylphosphonium ylide ob tained by treatment of ethylcyclohexa-2,4-dien-4-yl)-triphenylphosphon ium bromide with (BuLi)-Li-II in THF is stabilized by the abstraction of the CCl3 group to give (p-tolyl)triphenylphosphonium cation, which was isolated as the corresponding hydroxide. Conversely, an analogous pyridinium ylide, obtained by treatment of Z/E stereoizomeric -trichlo romethylcyclohexa-2,5-dien-4-yl)pyridinium bromide with a base (piperi dine in CD2Cl2, (BuLi)-Li-II in THF), at temperatures above -40 degree s C, undergoes a novel high-yield aromatizational skeletal rearrangeme nt with migration of the CCl3 group to position 2 of the heterocycle.