SYNTHESIS OF (E) AND O-1-PROPENYL]BROMOBIS(TRIPHENYLPHOSPHINE)PALLADIUM AND THE X-RAY CRYSTAL-STRUCTURE DETERMINATION FOR THE E-ISOMER

We report the preparation of (E)- and methoxyphosphinyl)oxy)-3-ethoxy- 3-oxo-1-propenyl]- bromobis(triphenylphosphine)palladium from the corr esponding ethyl (E)- d(Z)-3-bromo-2[(dimethoxyphosphinyl)oxy]propenoat e and the X-ray crystal structure determination for (E)-[2-((dimethoxy phosphinyl)oxy)-3-ethoxy-3-oxo- 1-propenyl]bromobis(triphenylphosphine )palladium. The (E)-palladium complex was reduced to (E)-3-[H-2]phosph oenolpyruvate by treatment with a mixture of trifluoroacetic acid-d/tr ifluoroacetic anhydride under strict anhydrous conditions. The H-1-NMR spectrum of the E-isomer obtained from the reduction of the palladium complex was identical to the H-1-NMR spectra of(E)-3-[H-2]phosphoenol pyruvate previously prepared by two different synthetic strategies. Th e X-ray structure of the palladium phosphoenolpyruvate analogue is the first X-ray structure of any 3-substituted phosphoenolpyruvate analog ue reported and along with its synthesis and transformation interrelat es the stereochemistry of several S-substituted phosphoenolpyruvate an alogues.