Benzene loss from trityl cations--a mechanistic study.

Triarylmethyl cations eliminate substituted benzene in the gas phase, upon activation. The mechanism of this process has been studied using deuterium labeling, substituent effects, and density functional theory calculations. It is shown that this apparently simple dissociation is in fact a complicated stepwise process that involves several consecutive hydride shifts. The combination of experimental evidence and computational results leads to a clear description of transition states and reaction intermediates.