Mechanistic studies using antihydrophobic agents

The hydrophobic effect-that decreases the solubilities of organic compounds in water and leads to aggregation of such species in water solution-can be diminished by various additives that we have termed antihydrophobic agents. When relatively small amounts are used, this may be the principal effect of such additives on solubilities and reaction rates. If so, quantitative studies can reveal the amount of hydrophobic surface that becomes isolated from the water solvent in a transition state; this is a direct guide to transition state structure. This paper describes the evidence for this new approach to elucidating transition state structures for some reactions in water, and the relevance of this information to the situation in other solvents.