Protic solvents in iminium ion catalysis

Research into iminium ion catalysis has expanded rapidly in recent years, but the majority of reports have not addressed understanding the processes taking place within the reaction flask. We have sought to understand these reactions and link them to computational models. Through exptl. and theor. investigations we have focussed on three principle observations for the Diels-Alder cycloaddn.: - Water increases the rate of reactions. - Water increases the e.e. of the isolated products. - Theor. models for the conformations of the active species do not agree. We present evidence offering insights into the crucial roles of protic solvents within these transformations. [on SciFinder(R)]