Enantiomeric enrichment of sulfoxides by preparative flash chromatography on an achiral phase

Diter, Patrick; Taudien, S.; Samuel, O.; Kagan, Henri B.

doi:10.1021/jo00081a015

Cited by 114 publications

(61 citation statements)

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“…This "hybrid model" defines a -Both "true" phase distribution functions, describing the absorp tion of the non-dimerized R-molecules and of the homochiral dimer (RR) i.e., functions f R and fm (JZqs. 6 and 8) are lumped in a single isotherm noted as hR:…”

Section: Definition Of An "Hybrid Model"mentioning

confidence: 99%

Enantiomeric enrichment of non-racemic mixtures of binaphthol with non-chiral packings

Nicoud¹,

Jaubert²,

Rupprecht³

et al. 1996

Chirality

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Section: Definition Of An "Hybrid Model"mentioning

confidence: 99%

Enantiomeric enrichment of non-racemic mixtures of binaphthol with non-chiral packings

Nicoud¹,

Jaubert²,

Rupprecht³

et al. 1996

Chirality

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“…90 ), clearly indicate that the relatively strong SDE phenomenon should be observed as a rule when a chiral sulfoxide is subjected to achiral gravity-driven chromatography. This means that the sulfinyl moiety should be considered as a SDE-phoric group 18,103 along with chiral amides 31,[51][52][53][54][55]102 and fluorine-containing compounds.…”

Section: Discussionmentioning

confidence: 87%

“…6 With (aminopropyl)silica gel as the stationary phase the same chromatographic behaviour was observed for 1,1'-binaphthol, 1-anthryl-2,2,2-trifluoroethanol, N-benzoylalanine methyl ester, a benzodiazepine, and chloromezanone. 7 It should be noted that this phenomenon is observed with HPLC, 2,4-11 medium-pressure liquid chromatography (MPLC), 12 and flash 13 and regular [14][15][16] chromatography. Before 2006 different definitions of this phenomenon were proposed in the literature: among them were "self-amplification of optical activity", 2 "enantiomer differentiation",…”

Section: Introductionmentioning

confidence: 89%

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Self-disproportionation of enantiomers (SDE) of chiral sulfur-containing compounds via achiral chromatography

Drabowicz¹,

Koprowski²,

Wzorek³

et al. 2017

Arkivoc

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This review presents a comprehensive, critical treatment of all the literature data related to the phenomenon of the SDE taking place during gravity-driven achiral chromatography of scalemic compounds bearing sulfoxide and thioamide functionalities. The discussion is focused on the SDE magnitude as a function of the structure iof the compound, composition of eluent and stationary phase, including some mechanistic details. An apparent possibility of application of the SDE phenomenon via achiral chromatography as a novel, emerging unconventional enantiomeric purification technique is also discussed.

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“…For 3-5, the acetates and phenols were separated by chromatography on silica gel eluted with toluene -ethyl ether (9:l) for 3 and 4 or hexane -ethyl acetate (4: 1) for 5. Kagan and co-workers recently reported an enantiomeric enrichment of sulfoxides during silica gel chromatography due to dimerization of the sulfoxides (47). We combined all the fractions containing the acetates or the phenols to avoid any such enrichment.…”

Section: Enantiomeric Puritymentioning

confidence: 99%

Kinetic resolution of sulfoxides with pendant acetoxy groups using cholesterol esterase: substrate mapping and an empirical rule for chiral phenols

Serreqi¹,

Kazlauskas²

1995

Can. J. Chem.

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Sulfoxides are valuable chiral auxiliaries because they direct the formation of carbon~arbon bonds. As a route to enantiomerically pure sulfoxides, we examined hydrolase-catalyzed kinetic resolution by hydrolysis of apendant acetoxy group. Screening hydrolases for the enantioselective hydrolysis of the acetate in 2-(methylsulfiny1)phenyl acetate, lb, identified cholesterol esterase (CE) as the most enantioselective enzyme. The enantiomeric ratio, E, ranged from 10 to 25, favoring the (R) configuration at sulfur. Competing chemical hydrolysis of l b caused the large range in the measured values of E. A small-scale (250 mg) resolution of (2)-l b yielded (S)-lb with >99% ee (1 1 % yield) after recrystallization. Changing the methyl substituent to phenyl or n-butyl did not significantly change the enantioselectivity (E = 10 and 15, respectively), but changing it to a chloromethyl substituent lowered the enantioselectivity slightly (E = 5). Changing the phenyl acetate to a naphthyl acetate (2-(phenylsulfiny1)phenyl acetate vs. 1-(phenylsulfiny1)-2-naphthyl acetate) increased the enantioselectivity from 10 to 19. In all cases CE favored the (R)-sulfoxide. To aid the design of new resolutions with CE, we propose an empirical rule that accounts for the observed enantiopreference of CE toward these 5 sulfoxides and 15 other chiral aryl acetates. This empirical rule uses both the size of the substituents and their conformational preferences to predict which enantiomer reacts faster.Key words: kinetic resolution, lipase, cholesterol esterase, sulfoxides, empirical rule, Resume : Les sulfoxydes sont des auxiliaires chiraux utiles parce qu'ils orientent la formation de liaisons carbone-carbone. Dans le but d'obtenir des sulfoxydes Cnantiomeriquement purs, on a examine la possibilitC d'utiliser une rtsolution cinCtique catalysCe par une hydrolase impliquant l'hydrolyse d'un groupe acCtoxy. Une Cvaluation des hydrolases pour leur capacitt a effectuer l'hydrolyse CnantiosClective de llacCtate de 2-(mCthylsulfinyl)phCnyle, lb, a permis d'identifier 13estCrase de cholestCro1 (CE) comme l'enzyme le plus CnantiosClectif. Le rapport CnantiomCrique, E, vane de 10 a 25 et il favorise la configuration (R) au niveau du soufre. L'hydrolyse chimique compCtitive du composC l b provoque les grandes variations observkes dans les valeurs mesurCes de E. Une rCsolution preparative 5 faible Cchelle (250 mg) du composC (2)-lb conduit, aprks recristallisation, au (S)-lb avec un ee >99% (rendement de 11%). Lorsqu'on change le substituant de mCthyle 2 phCnyle ou n-butylC, il n'y a pas de changement significatif d'CnantiosClectivitC (E = 10 et 15, respectivement); toutefois, si on le remplace par un chloromCthyle, 1'CnantiosClectivitC est 1Cgkrement diminuCe (E = 5). Si l'on remplace I'acttate de phCnyle par 1'acCtate de naphtyle (acCtate de 2-(phCnylsulfiny1)phtnyle vs. acetate de 1-(phCnylsulfiny1)-2-naphtyle) 1'CnantiosClectivitC passe de 10 a 19. Dans tous les cas, la CE favorise le (R)-sulfoxyde. Dans le but d'aider au dtveloppement de...

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Enantiomeric enrichment of sulfoxides by preparative flash chromatography on an achiral phase

Cited by 114 publications

References 0 publications

Enantiomeric enrichment of non-racemic mixtures of binaphthol with non-chiral packings

Enantiomeric enrichment of non-racemic mixtures of binaphthol with non-chiral packings

Self-disproportionation of enantiomers (SDE) of chiral sulfur-containing compounds via achiral chromatography

Kinetic resolution of sulfoxides with pendant acetoxy groups using cholesterol esterase: substrate mapping and an empirical rule for chiral phenols

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