Results 221 to 230 of about 667,303 (272)
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Rapid determination of enantiomeric excess: a focus on optical approaches.
Chem. Soc. Rev., 2012High-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 ...
Diana Leung, S. Kang, E. Anslyn
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Measuring enantiomeric excess on the fly
C&EN Global Enterprise, 2018Mitch Jacoby
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Analytical Chemistry, 2021
The determination of the enantiomeric excess and absolute configuration of chiral compounds is indispensable in synthetic, pharmaceutical, and biological chemistry.
Sumin Jang +4 more
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The determination of the enantiomeric excess and absolute configuration of chiral compounds is indispensable in synthetic, pharmaceutical, and biological chemistry.
Sumin Jang +4 more
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Enantiomeric Excesses in Meteoritic Amino Acids
Science, 1997Gas chromatographic-mass spectral analyses of the four stereoisomers of 2-amino-2,3-dimethylpentanoic acid (DL-α-methylisoleucine and DL-α-methylalloisoleucine) obtained from the Murchison meteorite show that the L enantiomer occurs in excess (7.0 and 9.1%, respectively) in both of the enantiomeric pairs.
J R, Cronin, S, Pizzarello
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Determination of enantiomeric excess by capillary electrophoresis
Electrophoresis, 2000Capillary electrophoresis (CE) is becoming an established method for the determination of chiral trace impurities. This paper provides an overview of the state of the art of CE for such determinations. Detection limits of 0.1% impurity is widely accepted as a minimum requirement for chiral trace impurity determinations.
L G, Blomberg, H, Wan
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Optical Analysis of Reaction Yield and Enantiomeric Excess: A New Paradigm Ready for Prime Time.
Journal of the American Chemical Society, 2018This Perspective highlights the advances of optical methods for asymmetric reaction discovery. Optical analysis allows for the determination of absolute configuration, enantiomeric excess and reaction yield that is amenable to high-throughput ...
Brenden T Herrera +4 more
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Enantiomeric Excesses and Electronic Chirality Measure
Journal of the American Chemical Society, 2003We present an approach to measure the amount of chirality in the electronic wave function and apply it to the study of a set of asymmetric aminohydroxylation reactions. The correlation coefficient between the chirality measure and the enantiomeric excesses is larger than 0.9 and suggests that this phenomenological approach can be a valuable tool to ...
Luca, Bellarosa, Francesco, Zerbetto
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Measurement of Enantiomeric Excess Using Molecularly Imprinted Polymers
Organic Letters, 2002[reaction: see text] A new method is presented for the measurement of enantiomeric excess (ee) utilizing molecularly imprinted polymers (MIPs). The method is demonstrated to be accurate and rapid, as the ee values can be calculated from straightforward concentration measurements.
Yizhao, Chen, Ken D, Shimizu
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Frozen Solution-Mediated Asymmetric Synthesis: Control of Enantiomeric Excess
The Journal of Organic Chemistry, 2020Asymmetric List-Mannich reactions were carried out in the frozen state to afford optically active adducts in moderate-to-good chemical yields and enantiomeric excesses (ee). The frozen solution exerts critical control of ee via entropy changes, in sharp contrast to the enthalpy-driven asymmetric reactions typically observed in homogeneous solvents ...
Koki Iijima +3 more
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Enantiomeric Excess of Amino Acids in Hydrothermal Environments
Origins of Life and Evolution of Biospheres, 2005In a simulated hydrothermal environment allowing fluid circulation between hot and cold regions repeatedly, D- and L-alanine molecules were racemized differently depending upon the concentration of alanine, whether D or L, present in the solution. In particular, the relative population of L-alanine was slightly more enhanced compared to that of D ...
Atsushi, Nemoto +5 more
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