Is the optical rotation sign/absolute configuration relationship still a problem? Examples taken from unnatural quaternary aminoacids

Ferron, Laurent; Guillen, Frédéric; Coste, Servane; Coquerel, Gérard; Plaquevent, Jean‐Christophe

doi:10.1002/chir.20296

Cited by 7 publications

(5 citation statements)

References 19 publications

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“…However, the chiral discrimination ability of TM-Cds in crystallized materials has been investigated and established only with a limited number of guest molecules. 9,[12][13][14] With the aim to understand some fundamental aspects of chiral discrimination by means of supramolecular complexation, we have recently studied the crystallization behavior of hostguest complexes formed with TM-Cds. [15][16][17] Using as model compounds a homologous series of racemic p-halogenated derivatives of phenylethanol, we have shown that enantiomeric enrichments obtained by crystallization depend on kinetic parameters, since the optical purity of the obtained solids are in most cases significantly affected by crystallization durations.…”

Section: Introductionmentioning

confidence: 99%

“…In the solid state, a higher amount of selective intermolecular interactions between the guest and its chiral environment may be reached, including favorable contacts with neighboring components in the crystal lattice. However, the chiral discrimination ability of TM-Cds in crystallized materials has been investigated and established only with a limited number of guest molecules. ,− …”

Section: Introductionmentioning

confidence: 99%

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Chiral Discrimination in Host−Guest Supramolecular Complexes. Understanding Enantioselectivity and Solid Solution Behaviors by Using Spectroscopic Methods and Chemical Sensors

et al. 2007

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Diastereomeric host-guest associations formed between permethylated-beta-cyclodextrin (TMbeta-Cd) and the two enantiomers of p-bromophenylethanol (pBrPE) were characterized in aqueous solution by NMR spectroscopy, revealing similar inclusion geometries and weak binding constants, whatever the guest configuration. These features were confirmed by hydrogenation experiments, and do not allow to account for the ability of TMbeta-Cd to resolve racemic pBrPE by successive crystallizations [Grandeury, A.; Petit, S.; Gouhier, G.; Agasse, V.; Coquerel, G. Tetrahedron: Asymmetry 2003, 14, 2143-2152]. The analysis, by means of solid-state NMR, oxidation experiments, and solubility measurements, of the two crystalline phases containing known proportions of guest enantiomers revealed identical inclusion geometries in a given phase, irrespective of the enantiomeric composition. The corresponding solid solutions were further characterized by the determination of an isothermal section (40 degrees C) in the relevant ternary phase diagram. It appears from all these data that chiral resolution mechanisms in this system can only be envisaged in terms of nucleation conditions of each crystal form (with its specific inclusion geometry) and enantiomeric recognition at crystal solution interfaces during the growth of each crystal packing.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Chiral Discrimination in Host−Guest Supramolecular Complexes. Understanding Enantioselectivity and Solid Solution Behaviors by Using Spectroscopic Methods and Chemical Sensors

et al. 2007

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“…According to this assignment, the structure of S-(+)-5-phenyl-5-ethylhydantoin was reported (Coquerel et al, 1993). Ferron et al (2006) determined the configuration of (R)-(À)-5-p-methylphenyl-5-methylhydantoin in a chlathrate compound with…”

Section: Database Surveymentioning

confidence: 99%

Crystal structures of (S)-(+)-5-(3-bromo/chloro-4-isopropoxyphenyl)-5-methylimidazolidine-2,4-dione

et al. 2016

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“…Using uniform experimental conditions (1:1 stoichiometry in aqueous medium), the resolution efficiency induced by crystallization was shown to be highly sensitive to kinetic parameters, since the de were, in most cases, strongly affected by crystallization durations. These diastereomeric complexes are composed of one guest molecule per TMβ-CD host, which is the usual stoichiometry for most of the complexes described in the literature. ,,,− …”

Section: Introductionmentioning

confidence: 99%

A Hybrid Mechanism in Chiral Discrimination Induced by Crystallization of Supramolecular Compounds

et al. 2012

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Host-guest complexes formed in aqueous medium between permethylated β-cyclodextrin (TMβ-CD) and racemic 1-(p-fluorophenyl)ethanol (p-F-PE) are studied. The crystalline complexes are characterized and their crystal structures are determined, revealing two sets of solid phases with specific abilities for chiral discrimination: on the one hand, a stable complete solid solution with two independent complexes per asymmetric unit exhibits a limited chiral recognition, and on the other hand, two metastable partial solid solutions with unusual 1:2 host-guest stoichiometries behave as diastereomeric complexes. The structural features of the 1:2 complexes and their study by means of molecular modeling show that these solid phases, described as cocrystals formed between one host-guest inclusion complex and one non-engulfed p-F-PE molecule, present a significant chiral discrimination occurring both inside the cyclodextrin and outside the macrocycle in a crystal lattice cavity. Therefore, the enantioselectivity observed in this system results from an interplay between molecular inclusion in the cyclodextrin and lattice inclusion. To our knowledge, it is the first report of such a hybrid mechanism. An overview of the crystal structures of the literature containing TMβ-CD is also achieved and allows their classification in four structural groups in relation to their crystal packing features.

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Is the optical rotation sign/absolute configuration relationship still a problem? Examples taken from unnatural quaternary aminoacids

Cited by 7 publications

References 19 publications

Chiral Discrimination in Host−Guest Supramolecular Complexes. Understanding Enantioselectivity and Solid Solution Behaviors by Using Spectroscopic Methods and Chemical Sensors

Chiral Discrimination in Host−Guest Supramolecular Complexes. Understanding Enantioselectivity and Solid Solution Behaviors by Using Spectroscopic Methods and Chemical Sensors

Crystal structures of (S)-(+)-5-(3-bromo/chloro-4-isopropoxyphenyl)-5-methylimidazolidine-2,4-dione

A Hybrid Mechanism in Chiral Discrimination Induced by Crystallization of Supramolecular Compounds

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