Number and Structure of Solvolysis Intermediates. Part 2. A Novel Example of the Common Ion Rate Depression Arising at the Stage of the Second Ion Pair Intermediate in the S<sub>N</sub>1 Solvolysis
The solvolysis of 2,2-dimethyl-1-(p-methoxyphenyl)propyl p-nitrobenzoate in phenol provides a novel example of the common ion salt effect (rate depression) which arises at the stage of the second ion pair intermediate (Int-2; the rear-side shielded ion pair intermediate), not the dissociated (free) carbocation intermediate as generally supposed so far. This example demonstrates that “the common ion