1,3-dipolar cycloaddition of phenyl azide to norbornene in aqueous solutions

Second-order rate constants for the cycloaddition of phenyl azide to norbornene were determined in aqueous solutions. In organic solvents this reaction shows a very small solvent effect. In highly aqueous media, however, remarkable accelerations are observed. The solvent dependence of the rate constants on solvent composition in mixed aqueous solutions resembles those observed for Diels-Alder reactions, most likely because both types of cycloadditions are mechanistically related