Gas‐phase stability of tertiary carbenium ions and rates of solvolysis of tertiary derivatives

The stability of tertiary carbenium ions was determined in the gas phase by ion cyclotron resonance (ICR) and by dissociative proton attachment (DPA). The rate constants for solvolysis of bridgehead derivatives correlate well with the stabilities of bridgehead carbenium ions, as determined by DPA and by ICR, but the ICR data of strained ions do not correlate, indicating rearrangements under the conditions of the ICR experiment. Simple acyclic tertiary derivatives solvolyze faster than predicted on the grounds of the stability of the respective carbenium ions. The effect of nucleophilic solvent participation on the rate of methanolysis of tertiary derivatives was investigated with (R)-3-chloro-3,7-dimethyloctane (17), which reacts with 77% inversion and 23% racemization. Copyright © 2000 John Wiley & Sons, Ltd.