Separation of Ring Polar and Resonance Effects on the Rate and Equilibrium Constants for Methoxide Ion-Promoted Addition of Methanol to N-Benzylideneanilines Substituted at the Benzylidene Moiety

Abstract

Rate and equilibrium constants for the title reaction (α-amino ether formation) at 25 o C in methanol are reported for (16) N-benzylideneani- lines (BAs) substituted at the benzaldehyde moiety. In contrast to a previous report dealing with BAs substituted at the aniline residue, it is shown that an uncatalyzed pathway competes with the methoxide ion- catalyzed reaction, these two processes corresponding to rate-limiting attachment of the lyate ion to the C=N bond of iminium ion and free imine, respectively. For the latter reaction pathway, the lifetimes of the amide-ion intermediates are long enough to allow a stepwise mecha- nism