Solution-Phase Energy Profiles for Trigonal Bipyramidal Species Postulated as Intermediates for the Hydrolysis of Methyl Ethylene Phosphate

We present the results of solution-phase ab initio and DFT investigations on the trigonal bipyramidal (TBP) intermediates postulated for the hydrolysis of methyl ethylene phosphate (MEP). A key intermediate for the hydrolysis would not be a TBP species with the hydroxyl group axial, but would be a TBP intermediate with the hydroxyl group equatorial. The reaction pathways through this intermediate are consistent with the experimental observations: not only exclusive ring opening in the dilute alkaline hydrolysis for MEP but also significant amount of exocyclic cleavage in the strong alkali can be rationalized.