Abstract N [BOND] H-containing formamidines combine a reasonably strong association to carboxylic acids to form complexes of well-defined geometries with a simultaneous proton- induced electrophilicity enhancement that allows for the exchange of their amine portion. The N [DOUBLE BOND] C (H)[BOND] NH fragment, therefore, undergoes “imine-like” exchange with N-containing nucleophiles. Because of the prototropic equilibrium, the N [ ...