Intramolecular Hydrogen‐Bonding Modulates the Nucleophilic Reactivity of Ammonium‐Peroxycarboxylates

Abstract

The ammonium‐peroxycarboxylic acid mesylates derived from γ‐aminobutyric acid, β‐alanine, and β‐piperidinopropionic acid were synthesized and characterized by spectroscopic methods and X‐ray crystallography. To study the nucleophilic reactivities of the corresponding ammonium‐ and amino‐peroxycarboxylates, the kinetics of their reactions with a series of benzhydrylium ions (Ar2CH+) were investigated in alkaline, aqueous solutions at 20 °C. Using sequential‐mixing stopped‐flow UV/Vis photometry, the rates of the reactions of the short‐lived nucleophiles with Ar2CH+ were determined and analyzed by the linear free energy relationship lg k = sN(N + E) furnishing nucleophilicity parameters (N, sN) of the peroxycarboxylates. Quantum chemical calculations indicate that the reactivity of the zwitterionic ammonium‐peroxycarboxylates is attenuated by intramolecular N–H···O hydrogen bonding.