An example of spontaneous resolution by sublimation

Paquette, Leo A.; Lau, Clifford J.

doi:10.1021/jo00384a056

Cited by 13 publications

(6 citation statements)

References 7 publications

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“…This substance, which crystallizes as a racemic compound, converts into a conglomerate phase by sublimation . This behavior is unprecedented in amino acids, although such a conversion has been apparently reported for a norbornenol derivative . Because a conglomerate is required for spontaneous resolution, the sublimed alcohol had indeed nonzero optical rotations consistent with a partial enantioenrichment.…”

Section: Sublimation: the Overlooked Pathwaymentioning

confidence: 93%

“…122 This behavior is unprecedented in amino acids, although such a conversion has been apparently reported for a norbornenol derivative. 123 Because a conglomerate is required for spontaneous resolution, the sublimed alcohol had indeed nonzero optical rotations consistent with a partial enantioenrichment. Unfortunately, the nature of the starting racemate was unclear, thus, hampering a conclusive statement; 55 it was just claimed that the nonsublimed material exhibited no optical rotation.…”

Section: Sublimation: the Overlooked Pathwaymentioning

confidence: 99%

“…Unfortunately, the nature of the starting racemate was unclear, thus, hampering a conclusive statement; 55 it was just claimed that the nonsublimed material exhibited no optical rotation. 123 In stark contrast, the situation of valine is unambiguous, and X-ray powder diffraction witnesses the conversion into a conglomerate under such a thermal treatment. More importantly, when started from scalemic mixtures (with an initial 40% ee), the conglomerate undergoes further enantioenrichment, which is particularly relevant in the front line ( Fig.…”

Section: Sublimation: the Overlooked Pathwaymentioning

confidence: 99%

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On the Physical Basis of Asymmetry and Homochirality

Cintas

Viedma

2012

Chirality

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Mirror symmetry breaking is ubiquitous in our visible universe taking place in elementary particles, atoms, and molecules. Molecular chirality is not biogenic in itself, although its detection is often considered a biosignature, a conjecture inferred from the fact that we do not know life devoid of homochirality. The question of whether there is a connection between the cosmic preference for one enantiomer, as imposed by the weak force, and the single chirality displayed on Earth is vividly debated. This article gives a glimpse on the origin of asymmetry from a cosmological perspective and on physical transformations that lead to an enantiomeric imbalance, leaving chemical reactions essentially aside. These processes are more plausible as sources of prebiotic chirality than asymmetric amplifications requiring unnatural substrates and conditions and fighting against racemization. The latter may actually be a friend, not foe, and a driving force for enantioselection.

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Section: Sublimation: the Overlooked Pathwaymentioning

confidence: 93%

Section: Sublimation: the Overlooked Pathwaymentioning

confidence: 99%

Section: Sublimation: the Overlooked Pathwaymentioning

confidence: 99%

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On the Physical Basis of Asymmetry and Homochirality

Cintas

Viedma

2012

Chirality

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“…16 Although such a racemic compound-conglomerate transformation lacks precedent in sublimed amino acids, it is not complete oddity and has been apparently observed in a few cases. 17,18 z…”

mentioning

confidence: 99%

“…16 Although such a racemic compound-conglomerate transformation lacks precedent in sublimed amino acids, it is not complete oddity and has been apparently observed in a few cases. 17,18 z Herein we extend this asymmetric amplification to other amino acids and their mixtures. Fig.…”

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confidence: 99%

Enantioenrichment in sublimed amino acid mixtures

et al. 2012

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The Scope of Catalytic Asymmetric Hydroboration/Oxidation with Rhodium Complexes of 1,1′‐(2‐Diarylphosphino‐1‐naphthyl)isoquinolines

Doucet

Fernández

Layzell

et al. 1999

Chemistry A European J

173

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Preformed cationic Rh complexes of the title ligands are effective for the asymmetric hydroboration/oxidation of vinylarenes at ambient temperature. These vinylarenes may carry E-or Z-b substituents but not a substituents. Enantiomer excesses of up to 97 % can be obtained in the most favourable cases. The enantioselectivity is moderately sensitive to the structure of the ligand: the difurylphosphino ligand gave superior results for electron-poor styrenes and the diphenylphosphino ligand the best results for electron-rich reactants. Mechanistic aspects are discussed.

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An example of spontaneous resolution by sublimation

Cited by 13 publications

References 7 publications

On the Physical Basis of Asymmetry and Homochirality

On the Physical Basis of Asymmetry and Homochirality

Enantioenrichment in sublimed amino acid mixtures

The Scope of Catalytic Asymmetric Hydroboration/Oxidation with Rhodium Complexes of 1,1′‐(2‐Diarylphosphino‐1‐naphthyl)isoquinolines

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