Nucleophilic Attack by Oxyanions on a Phosphate Monoester Dianion:  The Positive Effect of a Cationic General Acid

Abstract

The two negative charges on a phosphate monoester RO-PO32- at neutral pH provide a considerable electrostatic barrier toward reactions with nucleophilic reagents with a negative charge on the attacking atom. Electrostatic repulsion disappears when the hydrolysis of an aryl phosphate monoester is catalyzed by a neighboring cationic general acid. The hydrolysis of 8-dimethylammonium-1-phosphate (1) is catalyzed by oxyanions, fluoride anion, and hydroxylamines at similar rates.