Thermally induced resolution of racemic 1,1'-binaphthyl in the solid state

Wilson, Keith R.; Pincock, Richard E.

doi:10.1021/ja00839a033

Cited by 92 publications

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“…suitable for the production of optically pure binaphthyl, consists of a slight excess of one enantiomer (e.g., the R enantioiner in its 'eutectic' crystal form) and all the rest of the sample would be in the R,Sracemate form (1). When such a sample is heated, and provided that no nucleation of the other enantiomer (e.g., the S eutectic form) occurs, the growth of only R enantiomeric crystals proceeds at the expense of R,S-racemate and the entire sample is converted to optically pure R crystals.…”

Section: Resultsmentioning

confidence: 99%

“…The situation in the seeded samples at 150 "C therefore approaches the ideai for production of optically pure product as mentioned above. In this way, advantage can be taken of the phase relationships in the 1,l'-binaphthyl system in order to obtain, reproducibly, excellent resolutions in either direction in a single heating step (1).…”

Section: Resultsmentioning

confidence: 99%

“…1. The designation of the individual batch, the total weight, and the specific rotation in benzene are, respectively; S-1, 3.0 g, +1.4'; S-2, 4.0 g, +11.8'; S-3, 5.7 g, +1.8"; and R-1, 3.8 g, -11.0'.…”

Section: Methodsmentioning

confidence: 99%

“…The transformation of optically inactive into optically acti\-e 1,l '-binaphthyl iuay occur simply by heating a sample below its melting point (1). This is possible because the raceinate form (mp 145 ' C ) of this compound is unstable relative t o a mixture of separate R ( -) and S ( + ) enantiomeric crystals (mp 158 'C).…”

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The kinetics of the solid state transformation of racemic to optically active 1,1′-binaphthyl

Wilson¹,

Pincock²

1977

Can. J. Chem.

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The Dcportrr1er7t ofClzeriiiatr?.. fJr~i~.cr.sity of British Co/iir?7hici. Vcir~coii\,cr, B.C., Crir~citlri V6T1 W5Received August 24, 1976 KEITH R. WILSOK and RICHARD E. PINCOCK. Can. J. Chem. 55, 889 (1977). Rates of the solid state reaction which thermally converts racemic to optically active 1,l'-binaphthyl (mp 158 'C) have been determined at temperatures between 105 and 135 ' C using polycrystalline samples. The presence of a sufficiently uniform distribution of enantiomorphic seed crystals results in a smooth conversion of the racemate to the e~~tectic crystal forms of binaphthyl. Although it is possible to force the resol~ltion reaction almost to completion at higher temperatures (150 ' C ) where the melt phase is an intermediate, lower final specific rotations are obtained when only solid phases are involved (below 145 ' C ) because of the independent nucleation of racemic material from the reacting crystals. Both spontaneous nucleation and reaction rates in the solid state were increased by grinding the initially prepared samples and were decreased by the storage of samples. The Arrheni~~s activation energy of this phase transforn~ation giving optically active product is en. 60 kca1,mol in a variety of different samples. This is consistent with a mechanism in which a molecule of I,!'-binaphthyl attains considerable freedom from the racelnic solid in order to interconvert to its ellantio~ner and add to the growing optically active phase. racemique en une forme cristalline eutectiq~re du binaphtyl. I1 est possible de forcer la reaction de fagon obtenir une resolution pratiquement complete a des temperat~lres pl~rs Clevees (150 C ) alors que la phase fondue est un intermediaire; toutefois 011 obtient des rotations spkcifiques finales qui sont plus basses quaad ii n'y a que des phases solides d'imp1iqui.e~ (en dessi~s de 145 ^C ) et ce resirltat est dil a la nucleation independante du cornpose racenlique h partir des crirtaux q i~i rkagissent. La nucleation spontanee et les vitesses de reaction a l'etat solide sont toirtes les deux augmentees lorsque 1.011 broie les Cchantillons preparks initialement: toutefois elles sont diminuees lorsque l'on garde les echanrillons d'une f a~o n prolongke. L'energie d'activation d'Arrhenius dc cette transformation de phase conduisant a un produit optiquement aciif est d'environ 60 kcal'n~ol dans une grande quantite d'echantillons differenis. Cette valeur est en accord avec Lin mecanisme dans lequel une molic~rle de binaphtyl-l;l' devient tres libre d~: solide racemique de faqon 2 se convertir dans son enantiomere et B s'additionner a la phase optiquement active qiii est en croissance.[Traduit par le journal]

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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The kinetics of the solid state transformation of racemic to optically active 1,1′-binaphthyl

Wilson¹,

Pincock²

1977

Can. J. Chem.

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“…A melt of chiral 1,1 0 -binaphthyl can crystallize as a racemate (mp 145°C) or a conglomerate (mp 158°C), frequently with one enantiomorph in excess randomly created when the melt is suddenly cooled 13 or stirred at 150°C. 14 A supersaturated solution of easily interconverting complexes, [(L-ACL) 3 NiCl 2 ]M[(D-ACL) 3-NiCl 2 ] (ACL = a-amino-e-caprolactam), is capable of preferential crystallization, depending on the handedness of the seeding crystal used.…”

Section: Introductionmentioning

confidence: 99%