50484-75-8Relevant academic research and scientific papers
A REAFFIRMATION OF STEREOELECTRONIC CONTROL IN THE ALKALINE HYDROLYSIS OF METHYL AND ETHYL ETHYLENE PHOSPHATE
Gorenstein, David G.,Chang, Andrew,Yang, Ji-Charng
, p. 469 - 478 (2007/10/02)
A reinvestigation of the product distribution in the hydrolysis of ethyl and methyl ethylene phosphates has confirmed our earlier suggestion (Taira et al., J.Org.Chem., 1984, 4531) that the stereoelectronic effect is an important factor in these reactions.In contrast to the claims of Kluger and Thatcher (J.Am.Chem.Soc., 1985, 107, 6006; J.Org.Chem., 1986, 51, 207), the increase in exocyclic cleavage product, methanol, with increasing strong base is shown to arise from an artifactual side-reaction in the base catalyzed hydrolysis of methyl ethylene phosphate.The initial product of endocyclic cleavage, methyl hydroxyethyl phosphate, reacts with a second molecule of methyl ethylene phosphate to yield a "triester" dimer which subsequently releases methanol to yield a "diester" dimer.Although a small amount of exocyclic cleavage product is observed in strong alkali (2 - 4percent +/- 1.5percent for methyl ethylene phosphate and .5percent +/-1.5percent for ethyl ethylene phosphate) the proportion does not vary with alkali when the hydrolysis reaction is run under dilute conditions to minimize the dimerization reaction.Even these small proportions of exocyclic cleavage are still completely consistent with arguments regarding stereoelectronic control in these reactions.
Exocyclic Cleavage in the Alkaline Hydrolysis of Methyl Ethylene Phosphate: Evidence Against the Significance of Stereoelectronic Acceleration in Reactions of Cyclic Phosphates
Kluger, Ronald,Thatcher, Gregory R. J.
, p. 6006 - 6011 (2007/10/02)
The hydrolysis of methyl ethylene phosphate serves as a mechanistic probe of phosphate reactivity and as a model for enzyme catalysis.Early reports, based on proton NMR and GC analysis, indicated that observable amounts of exocyclic cleavage products are obtained in the alkaline hydrolysis reaction .However, later reports based on phosphorus NMR analysis of reactions in 5 M sodium hydroxide by advocates of a stereoelectronic theory indicated that, consistent with the theory, ring cleavage is the exclusive initial process .In the present study, the products of the reaction of methyl ethylene phosphate with hydroxide under a variety of conditions were determined by proton NMR and by phosphorus NMR with and without rapid quenching.Reactions of the products were also analyzed.The products of exocyclic cleavage, methanol and ethylene phosphate, are produced in the initial reaction to the extent that was reported in 1969.Subsequent reaction of the ring-cleaved products is too slow to account for the initial production of methanol.These data suggest that ring strain and apicophilicities of substituents, rather, than orbital interactions, account for the substantial differences in the reactivity of phosphate esters.
