Exam 3 Flashcards
What is enantiomeric excess
in non-racemic mixtures, on enantiomer is more abundant than the other, the composition of this mixture is described by enantiomeric excess
how do you calculate enantiomeric excess
(moles of one enantiomer- moles of other enantiomer) / total moles X 100%
What does FDA require for chiral drugs?
it requires a 100% ee of one enantiomer
when is the enantiomeric excess 100%
when a only a single enantiomer is present, it is pure
In reactions carried out with achiral reactants, what kind of product can form and why is this a problem?
this can create chiral products, in the absence of chiral influence, the outcome of the reaction can be racemic which is a 50:50 mix of enantionmers that has a 0% enantiomeric excess
what is the enantiomeric excess of a racemic mixture?
0%
what is a racemic synthesis
it gives a 50:50 mixture where neither enantiomer is favored and gives a 0% ee
what is asymmetric synthesis
it is where one enantiomer is favored over the others
what do we do if we have to do racemic mixtures?
we must separate the enantiomers
What is a chiral resolution
Chiral resolution, or enantiomeric resolution, is a process in stereochemistry for the separation of racemic mixture into their enantiomers
what is a chiral auxilary
stereogenic group or unit that is temporarily incorporated into an organic compound in order to control the stereochemical outcome of the synthesis.
What is a chiral resolution
Chiral resolution, or enantiomeric resolution, is a process in stereochemistry for the separation of racemic mixture into their enantiomers
what is the process of a chiral resolution
first the enantiomers need to be reacted with a chiral auxilary
the chiral auxilary will create two diastereomers that can be separated by conventional means
if we do a distillation, we can separate the two diastereomers into flasks and then remove the chiral auxilaries to have the two original enantiomers separated
what is the process of a chiral resolution
first the enantiomers need to be reacted with a chiral auxilary
the chiral auxilary will create two diastereomers that can be separated by conventional means
if we do a distillation, we can separate the two diastereomers into flasks and then remove the chiral auxilaries to have the two original enantiomers separated