Kinetic and mechanistic studies of proline-mediated direct intermolecular aldol reactions

Reaction progress kinetic analysis of the proline-mediated intermolecular aldol reaction shows that the rate depends on the concentrations of both the donor ketone1 and the electrophilic aldehyde 2, implying that enamine formation cannot be rate-determining. The observed kinetics and deuterium isotope effects are consistent with formation of the product iminium species as the rate-determining step. (C) 2009 Elsevier Ltd. All rights reserved.