Kinetic isotope and thermodynamic analysis of the nornicotine-catalyzed aqueous aldol reaction

A series of kinetic isotope effects and thermodynamic studies were performed to test key predictions of a computationally derived model for a nornicotine-catalyzed aqueous aldol reaction. The relative energies of the two computationally-derived transition states were challenged using the proton inventory, which demonstrated that a single water molecule from the solvent is involved in, or before, the rate-limiting step. These results suggest the importance of proton transfer in the aqueous aldol reaction and may assist the development of other aqueous organocatalytic processes.