AQUEOUS ACCELERATION OF THE CLAISEN REARRANGEMENT OF ALLYL VINYL ETHER - A HYBRID, EXPLICIT SOLVENT, AND CONTINUUM MODEL

A model of solvation, including both explicit water molecules and a de scription of the remaining solvent, based upon the polarizable continu um model is described and used to study the acceleration of the Claise n rearrangement of allyl vinyl ether observed in aqueous medium. The c alculations, at the ab initio HF/6-31G and MP2 levels, show that the major effect of the solvent is effectively modelled by the explicit wa ter molecules. This model yields a barrier lowering in excellent agree ment with experiment. The changes in the kinetic isotope effects arisi ng from hydration, predicted by our treatment, differ somewhat from th ose suggested by experiment.