Mechanisms of Hydrolysis of Phosphate Ester Derivatives of Phosphoenolpyruvic Acid

Keith J. Schray, Stephen Benkovic

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Abstract

The hydrolytic mechanisms of dibenzylphosphoenolpyruvic acid (I), benzylphenylphosphonoenol-pyruvic acid (II), and monobenzylphosphoenolpyruvic acid (III) involve cyclization by the undissociated carboxyl function to expel primarily the thermodynamically unfavorable leaving group, benzyl alcohol (80-90%). Products arising from enolic oxygen-phosphorus bond cleavage comprise the remaining pathway (10-15%). The pH-rate profiles and product studies in aqueous and hydroxylamine solutions suggest pentacovalent phosphorus intermediacy and the rapid, reversible formation of acyclic acyl phosphate or phosphonate in the reactions of I and II. Ill also forms acyclic acyl phosphate but apparently not reversibly under the experimental conditions. Phosphoenolpyruvic acid also cyclizes to the corresponding five-membered cyclic phosphate under these conditions. Hydrolysis in H218O indicates that decomposition of the cyclic acyl intermediates occuss with water attack on phosphorus rather than carbon. A rationale is offered for the product composition resulting from hydrolysis and hydroxylaminolysis for I-III and the unusual catalytic efficiency of the carboxyl function.

Original languageEnglish (US)
Pages (from-to)2522-2529
Number of pages8
JournalJournal of the American Chemical Society
Volume93
Issue number10
DOIs
Publication statusPublished - May 1 1971

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All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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