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 an d by ICR, but the ICR data of strained ions do not correlate, indicating re arrangements under the conditions of the ICR experiment. Simple acyclic ter tiary derivatives solvolyze faster than predicted on the grounds of the sta bility of the respective carbenium ions. The effect of nucleophilic solvent participation on the rate of methanolysis of tertiary derivatives was inve stigated with (R)-3-chloro-3,7-dimethyloctane (17), which reacts with 77% i nversion and 23% racemization. Copyright (C) 2000 John Wiley & Sons, Ltd.