Direct liquid chromatographic enantioseparation of chiral α- and β-aminophosphonic acids employing quinine-derived chiral anion exchangers: determination of enantiomeric excess and verification of absolute configuration

Zarbl, Elfriede; Lämmerhofer, Michael; Hammerschmidt, Friedrich; Wuggenig, Frank; Hanbauer, Martin; Maier, Norbert M.; Sajovic, Lisa; Lindner, Wolfgang

doi:10.1016/s0003-2670(99)00700-x

Cited by 57 publications

(35 citation statements)

References 15 publications

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“…Even harsh conditions (5 m HCl, 60 8C; Scheme 2) did not cleave the very stable N À P bond in (S)-(À)-6. Consequently, all protecting groups were removed by heating the solution at reflux in 6 m HCl to get the free a-aminophosphonic acid (S)-(À)-8 a to determine its enantiomeric excess by using HPLC [15] on a chiral stationary phase based on quinine carbamate, after pre-column derivatisation with the Sanger reagent (2,4-dinitrofluorobenzene) to yield the N-2,4-dinitrophenyl (DNP) derivative (S)-9 a. Surprisingly, its enantiomeric excess was found to be 50 % compared with 96 % for the starting (R)-1-phenylethylamine.…”

Section: (R)-1-phenyl-a C H T U N G T R E N N U N G Ethylamine ((R)-(mentioning

confidence: 99%

“…Surprisingly, its enantiomeric excess was found to be 50 % compared with 96 % for the starting (R)-1-phenylethylamine. We assigned the S configuration to a-aminophosphonic acid (À)-8 a on the basis that 1) its levorotatory p-methyl and p-nitro analogues have the S configuration, [11] 2) the binding model for DNP derivatives of chiral a-aminophosphonic acids gives the S configuration [15] for chiral stationary phases based on quinine carbamate and 3) migration of the dialkoxyphosphinyl group from the oxygen or nitrogen atom to the carbon atom followed, so far, a retentive course [16] consistently. Evidently, the intermediate a-aminocarbanion (R)-4 was configurationally unstable and partly enantiomerised (23 %) resulting in phosphonate (S)-(À)-6 with 50 % ee, in which the S enantiomer predominated.…”

Section: (R)-1-phenyl-a C H T U N G T R E N N U N G Ethylamine ((R)-(mentioning

confidence: 99%

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Preparation of α‐Aminobenzylphosphonic Acids with a Stereogenic Quaternary Carbon Atom via Microscopically Configurationally Stable α‐Aminobenzyllithiums

Kuliszewska

Hanbauer

Hammerschmidt

2008

Chemistry A European J

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The enantiomers of 1-phenylethylamine were phosphorylated with diethyl chlorophosphate/Et(3)N and then Boc-protected (Boc=tert-butoxycarbonyl) at the nitrogen atom. These phosphoramidates were metalated by using sBuLi/N,N,N',N'-tetramethylethylenediamine (TMEDA) to give alpha-aminobenzyllithiums that isomerised to alpha-aminophosphonates in yields of up to 80 % with retention of the configuration at the carbon atom. The intermediate tertiary organolithiums were found to be microscopically configurationally stable from -78 to 0 degrees C in Et(2)O. The protected alpha-aminophosphonates were deblocked by using boiling 6 M HCl or preferably Me(3)SiBr/(allyl)SiMe(3). When the Boc group was replaced by the diethoxyphosphinyl group, the alpha-aminobenzyllithium intermediate partially enantiomerised even at -78 degrees C and rearranged to yield an alpha-aminophosphonate with 50 % ee (ee=enantiomeric excess). Similarly, N-Boc-protected phosphoramidates derived from racemates and/or enantiomers of 1-(1-naphthyl)ethyl-, 1-indanyl- and 1,2,3,4-tetrahydro-1-naphthylamine or 1-azidoindan- and 1-azido-1,2,3,4-tetrahydronaphthalene were converted to aminophosphonates in good yields. Deblocking gave alpha-aminophosphonic acids of excellent enantiomeric excess (97-99 %), as determined by means of HPLC on a chiral ion-exchange stationary phase based on quinine carbamate. When racemic Boc-protected diethyl phosphoramidate derived from 1,2,3,4-tetrahydro-1-naphthylamine was metalated with LiTMP/TMEDA (TMP=2,2,6,6-tetramethylpiperidine), 1-hydroxyethylphosphonamidates resulted. The configuration of the main isomer was determined by means of a single-crystal X-ray structure analysis.

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Section: (R)-1-phenyl-a C H T U N G T R E N N U N G Ethylamine ((R)-(mentioning

confidence: 99%

Section: (R)-1-phenyl-a C H T U N G T R E N N U N G Ethylamine ((R)-(mentioning

confidence: 99%

Preparation of α‐Aminobenzylphosphonic Acids with a Stereogenic Quaternary Carbon Atom via Microscopically Configurationally Stable α‐Aminobenzyllithiums

Kuliszewska

Hanbauer

Hammerschmidt

2008

Chemistry A European J

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“…[7] Their asc.wiley-vch.de racemic counterparts have been prepared by reductive amination. 28 The enantiomeric excesses of their N-2,4-dinitrophenyl derivatives were determined by enantioselective HPLC on chiral, stationary phase based on O-9-t-butylcarbamoylquinine as chiral selector CSP II [33] and agreed (Table 5) with the ee of the starting bhydroxyphosphonates. The (R)-enantiomers of the derivatives of the b-aminophosphonic acids were stronger retained than the (S)-enantiomers.…”

mentioning

confidence: 88%

Enzymes in Organic Chemistry, 11:^[1] Hydrolase‐Catalyzed Resolution of α‐ and β‐Hydroxyphosphonates and Synthesis of Chiral, Non‐Racemic β‐Aminophosphonic Acids

Woschek¹,

Lindner²,

Hammerschmidt³

2003

Adv Synth Catal

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The enantioselective acylation of racemic diisopropyl a-and b-hydroxyphosphonates by hydrolases in t-butyl methyl ether with isopropenyl acetate as acyl donor is limited by the narrow substrate specificity of the enzymes. High enantiomeric excesses (up to 99%) were obtained for the acetates of (S)-diisopropyl 1-hydroxy-(2-thienyl)methyl-, 1-hydroxyethyl-and 1-hydroxyhexylphosphonate and (R)-diisopropyl 2-hydroxypropylphosphonate. The hydrolysis of a variety of b-chloroacetoxyphosphonates by the lipase from Candida cylindracea and protease subtilisin in a biphasic system gives (S)-b-hydroxyphosphonates (ee 51 ± 92%) enantioselectively. (S)-2-Phenyl-2-hydroxyethyl-and (S)-3-methyl-2-hydroxybutylphosphonates (ee 96% and 99%, respectively) were transformed into (R)-2-aminophosphonic acids of the same ee.

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“…Few diastereomeric resolutions using direct liquid chromatography employing quininederived chiral anion exchangers 39 or stereoselective capillary electrophoresis 40 have been reported. However, chemoenzymatic methods have not been widely used for the preparation of optically pure b-amino-a-hydroxy phosphonic esters.…”

Section: Enzymatic Resolutionsmentioning

confidence: 99%

Asymmetric Synthesis of α-Substituted-β-Amino Phosphonates and Phosphinates and β-Amino Sulfur Analogs

Palacios¹,

Alonso²,

Santos³

2005

Enantioselective Synthesis of Β-Amino Acids

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Direct liquid chromatographic enantioseparation of chiral α- and β-aminophosphonic acids employing quinine-derived chiral anion exchangers: determination of enantiomeric excess and verification of absolute configuration

Cited by 57 publications

References 15 publications

Preparation of α‐Aminobenzylphosphonic Acids with a Stereogenic Quaternary Carbon Atom via Microscopically Configurationally Stable α‐Aminobenzyllithiums

Preparation of α‐Aminobenzylphosphonic Acids with a Stereogenic Quaternary Carbon Atom via Microscopically Configurationally Stable α‐Aminobenzyllithiums

Enzymes in Organic Chemistry, 11:^[1] Hydrolase‐Catalyzed Resolution of α‐ and β‐Hydroxyphosphonates and Synthesis of Chiral, Non‐Racemic β‐Aminophosphonic Acids

Asymmetric Synthesis of α-Substituted-β-Amino Phosphonates and Phosphinates and β-Amino Sulfur Analogs

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Direct liquid chromatographic enantioseparation of chiral α- and β-aminophosphonic acids employing quinine-derived chiral anion exchangers: determination of enantiomeric excess and verification of absolute configuration

Cited by 57 publications

References 15 publications

Preparation of α‐Aminobenzylphosphonic Acids with a Stereogenic Quaternary Carbon Atom via Microscopically Configurationally Stable α‐Aminobenzyllithiums

Preparation of α‐Aminobenzylphosphonic Acids with a Stereogenic Quaternary Carbon Atom via Microscopically Configurationally Stable α‐Aminobenzyllithiums

Enzymes in Organic Chemistry, 11:[1] Hydrolase‐Catalyzed Resolution of α‐ and β‐Hydroxyphosphonates and Synthesis of Chiral, Non‐Racemic β‐Aminophosphonic Acids

Asymmetric Synthesis of α-Substituted-β-Amino Phosphonates and Phosphinates and β-Amino Sulfur Analogs

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Enzymes in Organic Chemistry, 11:^[1] Hydrolase‐Catalyzed Resolution of α‐ and β‐Hydroxyphosphonates and Synthesis of Chiral, Non‐Racemic β‐Aminophosphonic Acids