Accurate assay of enantiopurity of 1-hydroxy- and 2-hydroxyalkylphosphonate esters

Żymańczyk–Duda, Ewa; Skwarczyński, Mariusz; Lejczak, Barbara; Kafarski, Paweł

doi:10.1016/0957-4166(96)00143-7

Cited by 62 publications

(34 citation statements)

References 24 publications

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“…In the meantime, the absolute configurations of the 3-substituted-2-hydroxypropanephosphonates were preliminarily assigned on the basis of two features: (1) the measurement of δ values in 1 H NMR spectra of their α-methoxy-α-trifluoromethylphenyl acetic acid (MTPA) esters using the modified Mosher's method [9], and (2) according to the general experimental observation, bioreduction of ketones by baker's yeast usually obeys Prelog's rule [10]. In our case, the phosphonate group is the larger substituent, while the chloromethyl The ee(%) was determined by the use of quinine as a chiral solvating agent [7,8]. b The absolute configuration was determined according to Mosher's methods [9].…”

Section: Resultsmentioning

confidence: 99%

Enantioselective reduction of 2‐keto‐3‐haloalkane phosphonates by baker's yeast

Yuan

Wang

2001

Heteroatom Chemistry

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Section: Resultsmentioning

confidence: 99%

Enantioselective reduction of 2‐keto‐3‐haloalkane phosphonates by baker's yeast

Yuan

Wang

2001

Heteroatom Chemistry

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“…Measurements were obtained in CDCl 3 (99.5 at% D) at a temperature of 298 K. The optical purity of the products was estimated using quinine as a chiral solvating agent, which allowed a shift difference of 31 P NMR signals coming from hydroxyphosphonates enantiomer-bioreduction products to be achieved. 38 The degree of the conversion of the substrate was expressed as a percentage (%) and defined as:…”

Section: Chemical Reduction Of Substratesmentioning

confidence: 99%

Application of cyanobacteria for chiral phosphonate synthesis

Górak

Żymańczyk–Duda

2015

Green Chem.

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This is the first report on morphologically different strains of cyanobacteria: Arthrospira maxima, Nostoc cf-muscorum and Nodularia sphaerocarpa used for enantioselective bioreduction of selected, structurally different diethyl esters of oxophosphonic acids. The efficiency of the asymmetric hydrogen transfer was strongly dependent on the chemical structure of the substrates. Arthrospira maxima was active only toward diethyl (S)-2-oxopropylphosphonate (20% of yield, 99% of ee), whereas the application of Nostoc cf-muscorum as a biocatalyst allowed diethyl (S)-2-hydroxy-2-phenylethylphosphonate with a high enantiomeric excess (99%) and with 26% conversion degree to be obtained. Employing Nodularia sphaerocarpa led to the most spectacular result -diethyl (S)-2-hydroxy-2-phenylethylphosphonate with a degree of conversion of 99% and an optical purity of 92%. Enantioselective bioconversion of oxophosphonate with an aromatic side group located in the immediate vicinity of the carbonyl functionality was achieved for the first time. Additionally, flow cytometry showed excellent resistance of the cells of Nodularia sphaerocarpa against the examined xenobiotic -2-oxo-2-phenylethylphosphonate, these cells remain viable at the concentration of 10 mM of the bioconversion substrate compared to the 1 mM described previously for a fungal biocatalyst. The effect of cultivation medium, light source and light cycle (light : dark) on the effectiveness of the biotransformation process was examined.

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“…The enantiomeric purities of (R)-and (S)-12 were confirmed by 31 P NMR analysis using quinine as an enantiodifferentiating agent. 16,17 The crude alcohols were contaminated (less then 10%) with the respective oxaphospholanes (2R,3R)-and (2S,3S)-13, due to partial cyclisation of the c-hydroxypropylphosphonates 12 under basic conditions. Fortunately, oxaphospholanes 13 were easily removed chromatographically, although for the purpose of the syntheses of (R)-and (S)-6 their separation from the alcohol (R)-or (S)-12 is not necessary.…”

Section: Resultsmentioning

confidence: 99%