Atropisomerism in Doubly peri-Substituted 9-(2-methylbenzyl)triptycene Derivatives, 8-Chloro- and 8-Bromo-1,4-dimethyl-9-(2-methylbenzyl)triptycenes

Article abstract of DOI:10.1246/bcsj.65.1957

The 13C dynamic NMR study revealed that 9-(2-methylbenzyl)triptycene has an energy barrier to gear rotation of 11.8 kcal*mol^-1 (1 cal=4.184 J).Introduction of substituents at two of the peri-positions was expected to raise the barrier enough fo