Enantiomeric excess
A quantitative measure of the extent to which one enantiomer is present in excess over the other in a chiral mixture. It is one of the central parameters in chiral synthesis and in the quality control of chiral drugs.
Core Facts
In 1986, Kagan reported that in certain catalytic systems, the relationship between catalyst ee and product ee is nonlinear, that is, a positive nonlinear effect or a negative nonlinear effect.
Enantiomeric excess (ee value) is defined as the ratio of the difference between the concentrations of the two enantiomers to their sum, expressed as a percentage.
Timeline (last 90 days)
Enantiomeric excess (ee) is the core metric for quantitatively describing the purity of a chiral mixture, defined as the difference between the mole fractions of the two enantiomers divided by their sum; an ee of 0% represents a racemic mixture, and an ee of 100% represents complete single chirality.
Regulatory agencies such as the US FDA typically require single-enantiomer drugs to have an ee value of 99% or above.
The concept of ee value was systematically introduced into asymmetric catalysis research by Kagan et al. in the 1970s.
Enantiomeric excess (ee value) is used to quantitatively describe the degree of excess of one enantiomer relative to the other in a product; the "from 50:50 to 51:49" observed by Kogan corresponds to an ee value of about 2%.
Enantiomeric excess (ee value) is defined as the ratio of the difference between the concentrations of the two enantiomers to their sum, expressed as a percentage.
Enantiomeric excess is a commonly used indicator for measuring chiral purity, defined as the percentage of the difference between the concentrations of the two enantiomers divided by their sum, with 100% ee indicating complete single chirality.
Regulatory agencies such as the U.S. Food and Drug Administration (FDA) generally require chiral drugs to provide pharmacological and toxicological data for each enantiomer, and single-enantiomer products of many chiral drugs need to reach an ee value of more than 99% to be approved for marketing.
In 1986, Kagan reported that in certain catalytic systems, the relationship between catalyst ee and product ee is nonlinear, that is, a positive nonlinear effect or a negative nonlinear effect.
Enantiomeric excess (ee) is the standard measure of chiral purity; if a product contains 90% right-handed and 10% left-handed forms, then ee = 80%.
The Soai reaction can use an extremely low concentration of a chiral product as a template to replicate and amplify its own chiral information, ultimately generating products with a near-100% enantiomeric excess.
All Facts (10)
In 1986, Kagan reported that in certain catalytic systems, the relationship between catalyst ee and product ee is nonlinear, that is, a positive nonlinear effect or a negative nonlinear effect.
80%Partially VerifiedEnantiomeric excess (ee value) is defined as the ratio of the difference between the concentrations of the two enantiomers to their sum, expressed as a percentage.
65%UnverifiedEnantiomeric excess (ee) is the core metric for quantitatively describing the purity of a chiral mixture, defined as the difference between the mole fractions of the two enantiomers divided by their sum; an ee of 0% represents a racemic mixture, and an ee of 100% represents complete single chirality.
50%UnverifiedThe concept of ee value was systematically introduced into asymmetric catalysis research by Kagan et al. in the 1970s.
50%UnverifiedRegulatory agencies such as the US FDA typically require single-enantiomer drugs to have an ee value of 99% or above.
50%UnverifiedEnantiomeric excess (ee value) is used to quantitatively describe the degree of excess of one enantiomer relative to the other in a product; the "from 50:50 to 51:49" observed by Kogan corresponds to an ee value of about 2%.
50%UnverifiedEnantiomeric excess is a commonly used indicator for measuring chiral purity, defined as the percentage of the difference between the concentrations of the two enantiomers divided by their sum, with 100% ee indicating complete single chirality.
50%UnverifiedRegulatory agencies such as the U.S. Food and Drug Administration (FDA) generally require chiral drugs to provide pharmacological and toxicological data for each enantiomer, and single-enantiomer products of many chiral drugs need to reach an ee value of more than 99% to be approved for marketing.
50%UnverifiedEnantiomeric excess (ee) is the standard measure of chiral purity; if a product contains 90% right-handed and 10% left-handed forms, then ee = 80%.
50%UnverifiedThe Soai reaction can use an extremely low concentration of a chiral product as a template to replicate and amplify its own chiral information, ultimately generating products with a near-100% enantiomeric excess.
50%