Neighboring-group effects in the reactivities of hydroxyl groups in d-glucopyranosides

Abstract Glucosides having the hydroxyl groups at C-2 and C-3 individually substituted were treated with N , N -diethylaziridinium chloride in the presence of concentrations of sodium hydroxide ranging from 0.1 m to 6.0 m . Substitution of the hydroxyl group at C-2 greatly enhances the reactivities of the hydroxyl groups at C-3 and C-4 in dilute base but has less effect in more-concentrated base. Substitution of the hydroxyl group at C-2 has little effect upon the reactivity of the hydroxyl group at C-6. Substitution of the hydroxyl group at C-3 depresses the reactivity of the hydroxyl group at C-2 throughout the range of base concentrations, but this substitution enhances the reactivity of the hydroxyl group at C-6 to a great extent in dilute base and to a much smaller extent in the more concentrated base. Proposed explanations for these results are discussed.