Optical resolutions by inclusion complexation with a chiral host compound

Toda, Fumio

doi:10.1007/978-1-4020-2337-8_1

Cited by 19 publications

(25 citation statements)

References 61 publications

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“…The methods for enantiomeric resolution of racemates comprising nonracemizable enantiomers by crystallization are classified into two categories [9]; one is an indirect method using an external chiral element, such as a diastereomeric salt formation followed by fractional crystallization [10][11][12][13] or a diastereoselective host-guest inclusion complexation [14], and the other is a straightforward method to separate enantiomers by crystallization in the absence of an external chiral element. As the typical example of this latter category, well known is the "preferential crystallization" method to resolve a racemic conglomerate composed of a mixture of homochiral R and S crystals, in which by repeating crystallization from the supersaturated solution with the aid of its enantiopure seed crystals the enantiomerically enriched crystals are efficiently deposited in the alternating chirality sense [15][16][17][18].…”

Section: Open Accessmentioning

confidence: 99%

Chiral Symmetry Breaking Phenomenon Caused by a Phase Transition

2010

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Abstract:We report the mechanism and scope of "preferential enrichment", which is an unusual symmetry-breaking enantiomeric resolution phenomenon that is initiated by the solvent-assisted solid-to-solid transformation of a metastable polymorphic form into a thermodynamically stable one during crystallization from the supersaturated solution of certain kinds of racemic mixed crystals (i.e., solid solutions or pseudoracemates) composed of two enantiomers. The mechanism can well be interpreted in terms of a symmetrybreaking complexity phenomenon involving multistage processes that affect each other.

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Section: Open Accessmentioning

confidence: 99%

Chiral Symmetry Breaking Phenomenon Caused by a Phase Transition

2010

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“…The methods for enantiomeric resolution of racemates comprising nonracemizable enantiomers by crystallization are classified into two categories [17]: one is an indirect method using an external chiral element, such as diastereomeric salt formation followed by fractional crystallization [18][19][20][21][22][23][24][25] or a diastereoselective host-guest inclusion complexation [26,27]; the other is a straightforward method for separating enantiomers by crystallization in the absence of an external chiral element. As a typical example of this latter category, the "preferential crystallization" method is well known to resolve a racemic conglomerate composed of a mixture of homochiral R and S crystals in which, by repeated crystallization from the supersaturated solution with the aid of its enantiopure seed crystals, the enantiomerically enriched crystals are efficiently deposited in the alternating chirality sense [28][29][30][31].…”

Section: Enantiomeric Resolution By Crystallizationmentioning

confidence: 99%

Mechanism and Scope of Preferential Enrichment, a Symmetry-Breaking Enantiomeric Resolution Phenomenon

Tamura

Takahashi

Fujimoto

et al. 2006

Topics in Current Chemistry

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The mechanism of "preferential enrichment", an unusually symmetry-breaking enantiomericresolution phenomenon that is observed upon simple recrystallization of a certain kind of organic racemiccrystal from the usual organic solvents without any external chiral element, has been rationalized in termsof a complexity system involving multistage processes that affect each other. These processes comprise:(1) preferential homochiral molecular association to give one-dimensional (1D) R andS chains in solution; (2) formation of γ-form prenucleationaggregates consisting of the same homochiral 1D chains; (3) nucleation and crystal growth of the metastableγ-form crystal composed of irregular alignment of the homochiral 1D R andS chains; (4) the solvent-assisted solid-to-solid type of polymorphictransition of the incipient γ-form crystal into the more stable polymorphic form, such as the α-,δ-, or ε-form; and (5) partial crystal disintegration in the transformed crystal to releaseexcess R or S moleculesinto solution. Based on this mechanism, both induction and inhibition of preferential enrichment have beenachieved by controlling the mode of polymorphic transition during crystallization with appropriate seedcrystals. We call this forced polymorphic transition on the surface of a seed crystal "epitaxialtransition".

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“…By this method, very efficient resolution of various kinds of guest compounds has been accomplished. 8 By a similar procedure, stereoisomers with the same or very similar boiling points can be separated by distillation in the presence of a host compound. Much more interesting molecular movement in the solid state occurs between a chiral host and prochiral guest.…”

Section: Introductionmentioning

confidence: 99%

Formation of racemic compound crystals by mixing of two enantiomeric crystals in the solid state. Liquid transport of molecules from crystal to crystal

Toda¹,

Tanaka²,

Miyamoto³

et al. 1997

J. Chem. Soc., Perkin Trans. 2

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Mixing of powdered (؊)-and (؉)-enantiomer crystals in the solid state gives crystals of the racemic compound. This racemic crystal formation was followed by IR spectral measurement of a 1 : 1 mixture of (؊)-and (؉)-enantiomer crystals as a Nujol mull. As the formation of racemic crystals proceeds, the OH absorptions of the enantiomer disappear gradually and new OH absorptions due to the racemic compound appear. The formation of racemic crystals from enantiomer crystals has been studied for various kinds of chiral compounds: 2,2Ј-dihydroxy-1,1Ј-binaphthyl (1) and its derivatives, 10,10Ј-dihydroxy-9,9Ј-biphenanthryl (4), 2,2Ј-dihydroxy-4,4Ј,6,6Ј-tetramethylbiphenyl (5)

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Optical resolutions by inclusion complexation with a chiral host compound

Cited by 19 publications

References 61 publications

Chiral Symmetry Breaking Phenomenon Caused by a Phase Transition

Chiral Symmetry Breaking Phenomenon Caused by a Phase Transition

Mechanism and Scope of Preferential Enrichment, a Symmetry-Breaking Enantiomeric Resolution Phenomenon

Formation of racemic compound crystals by mixing of two enantiomeric crystals in the solid state. Liquid transport of molecules from crystal to crystal

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