Supramolecular catalysis of H/D exchange in pyruvate by macrocyclic polyamines involving a reactive iminium intermediate

Abstract

The activity of a series of macrocyclic polyamines as catalysts for proton exchange has been investigated. Structural and physico-chemical studies demonstrate the ability of these receptors to recognize pyruvate, form a covalent iminium intermediate and catalyse H/D exchange at the CH₃ position. The reaction follows Michaelis–Menten kinetics with a rate enhancement higher than 4.8 × 10⁵ (k_cat/k_uncat). The process also represents a potential entry into the catalysis of aldol condensation reactions.