1-Carboxyallenyl phosphate, an allenic analogue of phosphoenolpyruvate

1-Carboxyallenyl phosphate, the allenic homologue of phosphoenolpyruvate, has been synthesized in six steps. The key step in the synthesis is the isomerization of methyl 2-hydroxy-3-butynoate to the corresponding allenol and phosphorylation of this material. The allene is an excellent substrate for pyruvate kinase, undergoing reaction at more than half the rate of phosphoenolpyruvate. The allene is also a substrate for phosphoenolpyruvate carboxylase, being hydrolyzed by the enzyme rather than carboxylated. With both enzymes, the organic product is 2-oxo-3-butenoate, which gradually inactivates the enzymes by reaction with one or more sulfhydryl groups not at the active site.