High Throughput Screening Methods for Asymmetric Synthesis

Charbonneau, Valerie; Ogilvie, William W.

doi:10.2174/157019305774322725

Cited by 12 publications

(11 citation statements)

References 44 publications

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“…produces a noticeable separation of the enantiomers of camphor (vide supra), but the polarimetric detection readily establishes which camphor enantiomer is the major one in the case of a mixture of enantiomers. For camphor, the quantification could be done using a dual detection, UV for the sum of the two enantiomers and a polarimeter for the difference .…”

Section: Resultsmentioning

confidence: 99%

Attempts to separate (–)‐α‐thujone, (+)‐β‐thujone epimers from camphor enantiomers by enantioselective HPLC with polarimetric detection

Dahmane

Aamouche

Vanthuyne

et al. 2013

J of Separation Science

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In a first step, 26 chiral stationary phases (CSPs) have been screened for the separation of (-)-α-thujone, (+)-β-thujone epimers and camphor enantiomers by LC. The separations were monitored by a polarimeter detector. None of these CSPs provided a noticeable resolution for camphor enantiomers. The three components of a test mixture were clearly baseline separated on Chiralpak AS-H, Chiralpak AZ-H and TCI-MBS (poly(N-alpha-(S)-methylbenzylmaleimide) coated on silica gel) in a mobile phase composed of hexane/2-PrOH (99:1 v/v). Interestingly, for a preparative application, the three CSPs produced different elution orders for the three constituents of the mixture. In a second step, it is shown that the use of online polarimetric detection constitutes an unprecedented method to reveal the occurrence and the relative content of thujone epimers and the chirality of the major camphor enantiomer in crude essential oils. A proof of concept is illustrated on crude essential oils from Rosmarinus tournefortii, Artemisia herba alba and A. arborescens, which grow in Morocco and have several traditional uses there. In a third step, pure (+)-β-thujone was quantitatively collected from A. arborescens crude oil by semi-preparative HPLC on Chiralpak AZ-H monitored by a polarimeter.

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Section: Resultsmentioning

confidence: 99%

Attempts to separate (–)‐α‐thujone, (+)‐β‐thujone epimers from camphor enantiomers by enantioselective HPLC with polarimetric detection

Dahmane

Aamouche

Vanthuyne

et al. 2013

J of Separation Science

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“…[54][55][56] There are numerous types of chiral selectors which largely consist of charged cyclodextrins and polysaccharides. [57][58][59][60][61][62] The use of capillary array electrophoresis (CAE) with 96 capillaries in parallel has been implemented by Reetz et al for the analysis of chiral amines (10). 63 The amines were derivatized with fluorescein isothiocyanate (11) to create thiourea derivatives (12) for optical detection (Scheme 4), and g-cyclodextrin was used as the chiral selector.…”

Section: Capillary Electrophoresismentioning

confidence: 99%

“…These include reviews by Tsukamoto and Kagan on advances in determining ee, 6 Reetz on the use of evolutionary mutagenesis for producing large combinatorial libraries and determining ee using kinetics, 7 Traverse and Snapper on uses of methods of screening for asymmetric catalysts, 4 Finn on emerging methods in determining ee, 8 Pu on the use of fluorescent molecules for chiral recognition, 9 and a short review by Charbonneau and Ogilvie on methods to screen for asymmetric synthesis. 10 In contrast, this review focuses on methods based on optical signalling that have the potential for determining ee in a high-throughput workflow, along with a contrast to chromatographic approaches. Due to the limited space available, only optical techniques are discussed.…”

Section: Introductionmentioning

confidence: 99%

Rapid determination of enantiomeric excess: a focus on optical approaches

2012

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High-throughput screening (HTS) methods are becoming increasingly essential in discovering chiral catalysts or auxiliaries for asymmetric transformations due to the advent of parallel synthesis and combinatorial chemistry. Both parallel synthesis and combinatorial chemistry can lead to the exploration of a range of structural candidates and reaction conditions as a means to obtain the highest enantiomeric excess (ee) of a desired transformation. One current bottleneck in these approaches to asymmetric reactions is the determination of ee, which has led researchers to explore a wide range of HTS techniques. To be truly high-throughput, it has been proposed that a technique that can analyse a thousand or more samples per day is needed. Many of the current approaches to this goal are based on optical methods because they allow for a rapid determination of ee due to quick data collection and their parallel analysis capabilities. In this critical review these techniques are reviewed with a discussion of their respective advantages and drawbacks, and with a contrast to chromatographic methods (180 references).

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“…7,8 HTS methods 9 are becoming essential due to the rapid increase in the discovery of new asymmetric reactions using chiral catalysts created via parallel synthesis. 10 One logical approach to designing chiral inorganic complexes for enantioselective discrimination is to explore the actual chiral catalysts themselves.…”

Section: Introductionmentioning

confidence: 99%

Enthalpy- vs Entropy-Driven Complexation of Homoallylic Alcohols by Rhodium(I) Complexes

et al. 2011

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The thermodynamics of binding between several homoallylic alcohols and simple olefinic Rh(I) compounds was examined with 1H NMR spectroscopy and ITC. 1H NMR titrations revealed moderate binding of these alcohols with [Rh(COD)2]+ (1) and [Rh(COD)(CH3CN)2]+ (3), but weaker binding with [Rh(NBD)2]+ (2). ITC indicated that the complexation with [Rh(COD)2]+ is mainly governed by enthalpy whereas binding with [Rh(COD)(CH3CN)2]+ is entirely driven by entropy. The thermodynamic parameters for the homoallylic alcohol binding of Rh(I) complexes 1–3 are consistent with crystallographic data.

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High Throughput Screening Methods for Asymmetric Synthesis

Cited by 12 publications

References 44 publications

Attempts to separate (–)‐α‐thujone, (+)‐β‐thujone epimers from camphor enantiomers by enantioselective HPLC with polarimetric detection

Attempts to separate (–)‐α‐thujone, (+)‐β‐thujone epimers from camphor enantiomers by enantioselective HPLC with polarimetric detection

Rapid determination of enantiomeric excess: a focus on optical approaches

Enthalpy- vs Entropy-Driven Complexation of Homoallylic Alcohols by Rhodium(I) Complexes

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