Atropoisomerism in Biflavones: The Absolute Configuration of (−)-Agathisflavone via Chiroptical Spectroscopy

Covington, Cody L.; Fernando, M. S.; Silva, Jessica H. S.; Kuster, Ricardo Machado; Amorim, Mauro Barbosa de; Polavarapu, Prasad L.

doi:10.1021/acs.jnatprod.6b00395

Cited by 30 publications

(25 citation statements)

References 52 publications

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“…The DF and CID spectral methods have been used to aid in the determination of the ACs of several compounds. 22,[32][33][34][35][36][37][38] In addition, the experimental EDF spectra of binaphthol showed differences due to solvent complexation that followed the trend in solvent polarity. 39 In CDSpecTech, the similarity index SI can be calculated for EA, VA, and Raman spectra, and ESI for ECD, VCD, VROA, EDF, VDF, and VROA spectra, using the parametric function equation 19.…”

Section: Technical Detailsmentioning

confidence: 96%

“…Also, it is in the authors' experience that the standard error gives similar values as the block averaging methods for large numbers of snapshots. An illustrative case is shown in Figure , where the VCD spectra of (a S )‐agathisflavone in methanol averaged from 10 and 44 snapshots are displayed.…”

Section: Applicationsmentioning

confidence: 99%

“…Therefore, during similarity analysis between experimental and predicted VCD spectra, a Sim value of less than~0.4 and ESI value of less than~0.6 cannot unequivocally be used for AC Even though the current illustration (Figures 3, 4, and Tables 2, 3) is limited to VA, VCD, and VDF spectra, the CDSpecTech can do similar analyses for EA, ECD, and EDF and for vibrational Raman, VROA, and CID spectra as well. 22,[31][32][33][34][36][37][38]…”

Section: Similarity Overlap Analysismentioning

confidence: 99%

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CDSpecTech: A single software suite for multiple chiroptical spectroscopic analyses

Covington

Polavarapu

2017

Chirality

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The program CDSpecTech was developed to facilitate the analysis of chiroptical spectra, which include the following: vibrational circular dichroism (VCD) and corresponding vibrational absorption (VA) spectra; vibrational Raman optical activity (VROA) and corresponding vibrational Raman spectra; electronic circular dichroism (ECD) and corresponding electronic absorption (EA) spectra. In addition, the program allows for generating optical rotatory dispersion (ORD) as the Kramers-Kronig transform of ECD spectra. The simulation of theoretical spectra from transition strengths can be achieved using different bandshape profiles. The experimental and simulated theoretical spectra can be visually compared by displaying them together. A unique feature of CDSpecTech is performing spectral analysis using the ratio spectra; i.e., the dimensionless dissymmetry factor (DF) spectrum, which is the ratio of CD to absorption spectra, and the dimensionless circular intensity difference (CID) spectrum, which is the ratio of VROA to vibrational Raman spectra. The quantitative agreement between experimental and simulated theoretical spectra can also be assessed from the numerical similarity overlap between them. Two different similarity overlap methods are available. The program uses a graphical user interface which allows for ease of use and facilitates the analysis. All these features make CDSpecTech a valuable tool for the analysis of chiroptical spectra. The program is freely available on the World Wide Web.

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Section: Technical Detailsmentioning

confidence: 96%

Section: Applicationsmentioning

confidence: 99%

Section: Similarity Overlap Analysismentioning

confidence: 99%

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CDSpecTech: A single software suite for multiple chiroptical spectroscopic analyses

Covington

Polavarapu

2017

Chirality

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“…EDF spectral analysis is also being used, in addition to the use of EA and ECD spectra, for AC determination using chiroptical spectroscopy. Since prominent ECD bands need not be associated with larger dissymmetry factors, it is important that the experimental and predicted DF spectra should also match the correct AC.…”

Section: Results and Discissionmentioning

confidence: 99%

“…The closeness of DF similarity scores with and without normalization indicates a corresponding closeness among the magnitudes of intensities in the calculated and experimental ratio spectra. This method was applied to a number of small molecules to aid in the determination of their ACs …”

Section: Computationalmentioning

confidence: 99%

Absolute configuration of an axially chiral sulfonate determined from its optical rotatory dispersion, electronic circular dichroism, and vibrational circular dichroism spectra

et al. 2017

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The absolute configuration (AC) of an axially chiral sulfonate (aCSO), 3,5-dimethyl-2-(naphthalen-1-yl)-6-(naphthalen-1-yl)benzenesulfonate (labeled as aCSO5), was investigated using optical rotatory dispersion (ORD), electronic circular dichroism (ECD), and vibrational circular dichroism (VCD) spectroscopies. All three methods led to the same conclusion and the AC of aCSO5 is reliably determined to be (-)-(aR, aR), or conversely (+)-(aS, aS).

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Induction of Axial Chirality in 8‐Arylquinolines through Halogenation Reactions Using Bifunctional Organocatalysts

Miyaji

Asano

Matsubara

2017

Chemistry A European J

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The enantioselective syntheses of axially chiral heterobiaryls were accomplished through the aromatic electrophilic halogenation of 3-(quinolin-8-yl)phenols with bifunctional organocatalysts that control the molecular conformations during successive halogenations. Axially chiral quinoline derivatives, which have rarely been synthesized in an enantioselective catalytic manner, were afforded in moderate-to-good enantioselectivities through bromination, and an analogous protocol also enabled enantioselective iodination. In addition, this catalytic reaction, which allows enantioselective control through the use of mono-ortho-substituted substrates, allowed the asymmetric synthesis of 8-arylquinoline derivatives bearing two different halogen groups in high enantioselectivities.

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Atropoisomerism in Biflavones: The Absolute Configuration of (−)-Agathisflavone via Chiroptical Spectroscopy

Cited by 30 publications

References 52 publications

CDSpecTech: A single software suite for multiple chiroptical spectroscopic analyses

CDSpecTech: A single software suite for multiple chiroptical spectroscopic analyses

Absolute configuration of an axially chiral sulfonate determined from its optical rotatory dispersion, electronic circular dichroism, and vibrational circular dichroism spectra

Induction of Axial Chirality in 8‐Arylquinolines through Halogenation Reactions Using Bifunctional Organocatalysts

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