J. Org. Chem. 1984,49. 5189-5194 that the major solvent effects on reactivity can be correlated with two solvent parameters, in our work Y and solvent nucleophilicity N; however we disagree on how the two solvent properties are extracted from the experimental data to give a physically significant empirical model of solvation effects on reactivity in protic media. The solvent polarity scales based on solvatochromism appear to be less suitable for probing heterolytic reactivity, possibly because of contributions from solvation effects which destabilize excited states.
Experimental Section Chemicals. 1-Adamantyl iodide (I, X = I) was prepared and
purified by literature procedures mp 75-77 "C mp 75-76 "C). Trifluoroethanol, hexafluoroisopropyl alcohol, and ethanol were purified as described p r e v i ~ u s l y .Commercially ~~ available samples of acetone, dioxan and methanol (Fisons, dried and distilled), acetic acid (BDH, Arista), and formic acid (BDH, AR) were used directly. Acetone, ethanol, and methanol samples were shown by Karl Fischer titration to contain
