DUAL MECHANISMS OF THE ARYL GROUP ROTATION IN 9-(3,5-DIMETHYLBENZYL)TRIPTYCENE DERIVATIVES

Abstract
9-(3,5-Dimethylbenzyl)triptycene derivatives exchange their two m-methyl groups by two mechanisms: rotation about the CH2–Ar bond and synchronous rotation about the CH2–Ar and the CH2–C9 bonds. The relative contribution of the processes is dependent on the peri-substituents.