chapter 5 stereoisomerism '13 bw(1)
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1!
Chapter 5. Stereoisomerism
"Junha Jeon!
Department of Chemistry!University of Texas at Arlington!
Arlington, Texas 76019!"!
Chem 2321, Fall ‘13!
Background: Stereoisomers!
the same connectivity between atoms !but different 3-diemensional spatial arrangement of their atoms !
Background: Stereoisomers!
the same connectivity between atoms !but different 3-diemensional spatial arrangement of their atoms !
Background: Stereoisomers!
the same connectivity between atoms !but different 3-diemensional spatial arrangement of their atoms !
Talidomide!
(RS)-2-(2,6-dioxopiperidin-3-yl)-1H-isoindole-1,3(2H)-dione!
ignore!
Background: Stereoisomers!
the same connectivity between atoms !but different 3-diemensional spatial arrangement of their atoms !
Talidomide!
– developed to treat morning sickness!
– found to be a cause of birth defects (10,000-20,000 victims in 46 countries)!!! !
5.1 Isomerism!
Nonidentical molecules that have the same formula!
2!
Isomerism!
Nonidentical molecules that have the same formula!
cis–trans Stereoisomerism: Ring System"
the same connectivity, but not identical"
v cis: two groups are on the same side.!
v trans: two groups are on opposite sides."
More generally, !cis-trans Isomerism: differ in the positions of atoms (or groups) relative to a
reference plane
cis–trans Stereoisomerism! ! ! ! !"
v cis: two groups are on the same side.!
v trans: two groups are on opposite sides."
More generally, !cis-trans Isomerism: differ in the positions of atoms (or groups) relative to a
reference plane – different compounds
cis–trans Stereoisomerism: Double Bonds ! ! ! !!!
To maintain orbital overlap in the pi bond, !
C=C double bonds cannot freely rotate.!
cis–trans Stereoisomerism: Double Bonds ! ! ! !!!
cis–trans Stereoisomerism: Double Bonds ! ! ! !!!
3!
cis–trans Stereoisomerism: Double Bonds ! ! ! !!!
5.2 Introduction to Stereoisomerism!
Many other important stereoisomers are available!!!
So far,!
1. Stereoisomers, 2.Constitutional isomers!
5.2 Introduction to Stereoisomerism!
Many other important stereoisomers are available!!!
So far,!
1. Stereoisomers, 2.Constitutional isomers!
a) Conformational isomers b) cis-trans isomers !
5.2 Introduction to Stereoisomerism!
Many other important stereoisomers are available!!!
So far,!
1. Stereoisomers, 2.Constitutional isomers!
a) Conformational isomers b) cis-trans isomers !
and!
c) Enantiomers d) Diastereomers!
Molecular Models are now useful!!"
Chirality!
v Two identical objects are superimposable on their mirror images.!
!
4!
Chirality!
v Two objects are nonsuperimposable on their mirror images – not identical.!
!
Chirality!
v Two objects are nonsuperimposable on their mirror images – not identical.!
v Chiral molecules are nonsuperimposable on their mirror images and hold handedness. !
!
Chirality!
v Two objects are nonsuperimposable on their mirror images – chiral.!
v Chiral molecules are nonsuperimposable on their mirror images and hold handedness. !
!
Chirality!
v Two identical objects are superimposable on their mirror images – achiral.!
Chirality Centers!
v Two objects are nonsuperimposable on their mirror images – chiral.!
v Chiral molecules are nonsuperimposable on their mirror images and hold handedness. !
!
Chirality Centers!
v Chiral molecules are nonsuperimposable on their mirror images !!and hold handedness. !
v A central tetrahedral carbon atom bearing 4 different groups !
5!
Chirality Centers!
v Chiral molecules are nonsuperimposable on their mirror images !!and hold handedness. !
v A central tetrahedral carbon atom bearing 4 different groups! : chirality center (a.k.a. stereogenic center, stereocenter …)!
Chirality Centers!
v Chiral molecules are nonsuperimposable on their mirror images !!and hold handedness. !
v A central tetrahedral carbon atom bearing 4 different groups! : chirality center (a.k.a. stereogenic center, stereocenter …)!
Enantiomers!
v When a compound is chiral, it should have one nonsuperimposable mirror image, called its enantiomer (“opposite”); a pair of enantiomers!
Enantiomers!
v When a compound is chiral, it should have one nonsuperimposable mirror image, called its enantiomer (“opposite”); a pair of enantiomers!
v In other words,!
!Enantiomers: two molecules that are mirror images but are nonidentical and nonsuperimposible.!
!
Configuration ! ! ! ! ! !!
v Configuration: the spatial arrangement of the atoms of a molecular entity – the
three-dimensional orientation of substituents (cf. conformation: a variety of
possible three-dimensional shapes)"!
XY
XY
XY
XY
Designation Configuration: Need a Language !
draw!
6!
Configuration: the Cahn-Ingold-Prelog System!
1. Using atomic numbers, prioritize the four groups attached to the chirality center.!
2. Arrange the molecule in space so the lowest priority group faces away from you (on a dash).!
3. Count the group priorities 1…2…3 to determine whether the order progresses in a clockwise or counterclockwise direction.!
– Descriptors: Clockwise = R and Counterclockwise = S!
!
!
Configuration: the Cahn-Ingold-Prelog System!
1. Using atomic numbers, prioritize the four groups attached to the chirality center.!
2. Arrange the molecule in space so the lowest priority group faces away from you (on a dash)!
3. Count the group priorities 1…2…3 to determine whether the order progresses in a clockwise or counterclockwise direction!
– Descriptors: Clockwise = R and Counterclockwise = S!
!
!
1. Using atomic numbers, prioritize the four groups attached to the chirality center.!
2. Arrange the molecule in space so the lowest priority group faces away from you (on a dash).!
3. Count the group priorities 1…2…3 to determine whether the order progresses in a clockwise or counterclockwise direction!
– Descriptors: Clockwise = R and Counterclockwise = S!
!
!
Configuration: the Cahn-Ingold-Prelog System! Configuration: the Cahn-Ingold-Prelog System!
1. Using atomic numbers, prioritize the four groups attached to the chirality center.!
2. Arrange the molecule in space so the lowest priority group faces away from you (on a dash).!
3. Count the group priorities 1…2…3 to determine whether the order progresses in a clockwise or counterclockwise direction.!
– Descriptors (configuration of a chirality center): !
Clockwise = R"
Counterclockwise = S!
!
!
Configuration: the Cahn-Ingold-Prelog System!
1. Using atomic numbers, prioritize the four groups attached to the chirality center.!
2. Arrange the molecule in space so the lowest priority group faces away from you (on a dash).!
3. Count the group priorities 1…2…3 to determine whether the order progresses in a clockwise or counterclockwise direction.!
– Descriptors (configuration of a chirality center): !
Clockwise = R"
Counterclockwise = S!
!
!
Configuration: the Cahn-Ingold-Prelog System!
1. Using atomic numbers, prioritize the four groups attached to the chirality center.!
2. Arrange the molecule in space so the lowest priority group faces away from you (on a dash).!
3. Count the group priorities 1…2…3 to determine whether the order progresses in a clockwise or counterclockwise direction.!
– Descriptors (configuration of a chirality center): !
Clockwise = R"
Counterclockwise = S!
!
!
7!
Assigning Priorities to All Four Groups! Assigning Priorities to All Four Groups!
Assigning Priorities to All Four Groups! Assigning Priorities to All Four Groups!1!
3!2!
4!
Then configuration?!
Assigning Priorities to All Four Groups!1!
3!2!
4!
(R)!
Assigning Priorities to All Four Groups!
8!
Assigning Priorities to All Four Groups!1!
3!2!
4!
Then configuration?!
Assigning Priorities to All Four Groups!1!
3!2!
4!
(R)!
Assigning Priorities to All Four Groups! Assigning Priorities to All Four Groups!
1!3!2!
4!
Then configuration?!
Assigning Priorities to All Four Groups!
1!3!2!
4!(S)!
Designating Configurations!
Nomenclature for alcohols: put “–ol” at the end of names!
9!
Designating Configurations!
Nomenclature for alcohols: put “–ol” at the end of names!
Designating Configurations!
Nomenclature for alcohols: put “–ol” at the end of names!
Question: How Many Chirality Centers?!
OH
O
Ibuprofen
Advil®
Question: How Many Chirality Centers?!
OH
O
Ibuprofen
Advil®
5.4 Optical Activity!
v Enantiomers: Identical physical properties (e.g. meting point, boiling point…)!
v Why?!
Optical Activity!
v Enantiomers: Identical physical properties (e.g. meting point, boiling point…)!
v Why? Intermolecular interactions should be identical.!
10!
Optical Activity!
v Enantiomers: Identical physical properties (e.g. meting point, boiling point…)!
v Why? Intermolecular interactions should be identical.!
!
!
!
!
!
!
!
v Are enantiomers distinguishable by any means?!
Optical Activity!
v Enantiomers: rotating in opposite directions upon exposure to plane-polarized light. !
v Plane-polarized light: the orientation of the electric field!
!
!
!
!
!
!
Optical Activity!
v Enantiomers: rotating in opposite directions upon exposure to plane-polarized light. !
v Plane-polarized light?!
!
!
!
!
!
Optical Activity!
v Enantiomers: rotating in opposite directions upon exposure to plane-polarized light. !
v Plane-polarization of light? the orientation of the electric field!
!
!
!
!
!
unpolarized light"
polarized light"
Optical Activity!
v Enantiomers: rotating in opposite directions upon exposure to plane-polarized light. !
v Plane-polarized light: only photons of a particular polarization (one directional light) passed through a polarizing filter!
!
!
!
!
!
Polarimetry!
v When plane polarized light is directed through a sample of a chiral compound, the plane that the light travels on will rotate: optically active !
v Optically inactive: the plane that the light travels on will not rotate.!
!
!
!
!
!
11!
Polarimetry!
v When plane polarized light is directed through a sample of a chiral compound, the plane that the light travels on will rotate: optically active !
v Optically inactive!
v Polarimeter: The light source: a Na lamp (589 nm, i.e. the sodium D line)!
!
!
!
!
!
v Enantiomers: rotating in opposite directions upon exposure to plane-polarized light. !
v Specific rotation [α]: the observed rotation, α under the standard condition [a standard concentration (1 g/mL) and pathlength (1 dm)], but the temperature effect?!
Specific Rotation!
v Enantiomers: rotating in opposite directions upon exposure to plane-polarized light. !
v Specific rotation [α]: the observed rotation, α under the standard condition [a standard concentration (1 g/mL) and pathlength (1 dm)], but the temperature effect?!
Specific Rotation!
d: dextrorotatory!l: levorotatory!
v Enantiomers: rotating in opposite directions upon exposure to plane-polarized light. !
v Specific rotation [α]: the observed rotation, α under the standard condition [a standard concentration (1 g/mL) and pathlength (1 dm)], but the temperature effect?!
Specific Rotation!
(+)-2-Bromobutane!(–)-2-Bromobutane!
v R and S refer to the configuration of the chirality center:!
independent of measurement conditions !
v (+) and (–) signs refer to the direction that the plane of light is rotated:!
dependent of measurement conditions (determined experimentally)!
Therefore, no relationship between the R/S configuration and !
the direction of light rotation (+/–)!!
Relationship Between R/S Configuration and Specific Rotation!
(+)-2-Bromobutane!(–)-2-Bromobutane!
v R and S refer to the configuration of the chirality center:!
independent of measurement conditions !
v (+) and (–) signs refer to the direction that the plane of light is rotated:!
dependent of measurement conditions (determined experimentally)!
Therefore, no relationship between the R/S configuration and !
the direction of light rotation (+/–)!!
Relationship Between R/S Configuration and Specific Rotation!
(+)-2-Bromobutane!(–)-2-Bromobutane!
12!
v R and S refer to the configuration of the chirality center:!
independent of measurement conditions !
v (+) and (–) signs refer to the direction that the plane of light is rotated:!
dependent of measurement conditions (determined experimentally)!
Therefore, NO relationship between the R/S configuration and !
the direction of light rotation (+/–)!!
Relationship Between R/S Configuration and Specific Rotation!
(+)-2-Bromobutane!(–)-2-Bromobutane!
Enantiomeric Excess!
v Enantiomerically pure (enantiopure, optically pure): only a single enantiomer!
v Racemic mixture (optically inactive): equal amounts of both enantiomers!
v Scalemic mixture (optically active): unequal amounts of both enantiomers (non-racemic chiral compound) – enantioenriched!
v Enantiomeric excess (ee): % ee"
Enantiomeric Excess!
v Enantiomerically pure (enantiopure, optically pure): only a single enantiomer!
v Racemic mixture (optically inactive): equal amounts of both enantiomers!
v Scalemic mixture (optically active): unequal amounts of both enantiomers (non-racemic chiral compound) – enantioenriched!
v Enantiomeric excess (ee): % ee"
Enantiomeric Excess!
v Enantiomerically pure (enantiopure, optically pure): only a single enantiomer!
v Racemic mixture (optically inactive): equal amounts of both enantiomers!
v Scalemic mixture (optically active): unequal amounts of both enantiomers (non-racemic chiral compound) – enantioenriched!
v Enantiomeric excess (ee): % ee"
Enantiomeric Excess!
v Enantiomerically pure (enantiopure, optically pure): only a single enantiomer!
v Racemic mixture (optically inactive): equal amounts of both enantiomers!
v Scalemic mixture (optically active): unequal amounts of both enantiomers (non-racemic chiral compound) – enantioenriched!
v Enantiomeric excess (ee): % ee"
Enantiomeric Excess: Practice II!
v Enantiomeric excess (ee): % ee"
Problem 1: enantiomeric excess of a solution (R)-2-bromobutane where the
observed specific rotation was found to be –10°?!
!!
!
!
!
!
!
!
!
(+)-2-Bromobutane!(–)-2-Bromobutane!
13!
Enantiomeric Excess: Practice II!
v Enantiomeric excess (ee): % ee"
Problem 1: enantiomeric excess of a solution (R)-2-bromobutane where the
observed specific rotation was found to be –10.2°?!
!!
!
!
!
!
!
!
!
(+)-2-Bromobutane!(–)-2-Bromobutane!
à % ee = (–10.2°)/(–23.1°) !
= –44.2% ee"
Enantiomeric Excess: Practice I!
v Enantiomeric excess (ee): % ee"
Problem 2: enantiomeric excess of a solution containing 70% (R)-2-bromobutane
and 30% (S)-2-bromobutane?!
!!
!
!
!
!
!
!
!
(+)-2-Bromobutane!(–)-2-Bromobutane!
Enantiomeric Excess: Practice I!
v Enantiomeric excess (ee): % ee"
Problem 2: enantiomeric excess of a solution containing 70% (R)-2-bromobutane
and 30% (S)-2-bromobutane?!
!!
!
!
!
!
!
!
!
(+)-2-Bromobutane!(–)-2-Bromobutane!
(R) enantiomer – (S) enantiomer
(R) enantiomer + (S) enantiomerX 100%% ee =
Enantiomeric Excess: Practice I!
v Enantiomeric excess (ee): % ee"
Problem 2: enantiomeric excess of a solution containing 70% (R)-2-bromobutane
and 30% (S)-2-bromobutane?!
!!
!
!
!
!
!
!
!
(+)-2-Bromobutane!(–)-2-Bromobutane!
à 40% ee (40% excess of the !
R stereoisomer)"
(R) enantiomer – (S) enantiomer
(R) enantiomer + (S) enantiomerX 100%% ee =
Stereoisomeric Relationships!
Diastereomers: stereoisomers that are not mirror images of one another. !(e.g. cis-trans isomers) !
!
!
!
!
!
!
!
Stereoisomeric Relationships!
Diastereomers: stereoisomers that are not mirror images of one another. !(e.g. cis-trans isomers) !
!
!
!
!
!
!
!
14!
Diastereomers: stereoisomers that are not mirror images of one another. !(e.g. cis-trans isomers)!
v Let’s consider compounds containing more than !
one chirality center.!
v How many chirality centers? And how many possible!
stereoisomers?!
!
Stereoisomeric Relationships!
Diastereomers: stereoisomers that are not mirror images of one another. !(e.g. cis-trans isomers)!
v Let’s consider compounds containing more than !
one chirality center.!
v How many chirality centers? And how many possible!
stereoisomers?!
!
Stereoisomeric Relationships!
Diastereomers: stereoisomers that are not mirror images of one another. !(e.g. cis-trans isomers)!
v Let’s consider compounds containing more than !
one chirality center.!
v How many chirality centers? And how many possible!
stereoisomers?!
!
Stereoisomeric Relationships!
Diastereomers: stereoisomers that are not mirror images of one another. !(e.g. cis-trans isomers)!
v Let’s consider compounds containing more than !
one chirality center.!
v How many chirality centers? And how many possible!
stereoisomers?!
!
Stereoisomeric Relationships!
Diastereomers: stereoisomers that are not mirror images of one another. !(e.g. cis-trans isomers)!
v Let’s consider compounds containing more than !
one chirality center.!
v How many chirality centers? And how many possible!
stereoisomers? 22 = 4!
!
Diastereomeric Relationships!
v Let’s consider compounds containing three chirality centers. And how many possible stereoisomers?!
!
Diastereomeric Relationships!
15!
v Let’s consider compounds containing three chirality centers. And how many possible stereoisomers? 23 = 8 (4 pairs of enantiomers) !
!
!
Diastereomeric Relationships! Symmetry and Chirality!
v Compounds containing more than one chirality will be chiral: not always true!!!
!
Are they chiral?!
!
chiral! achiral!
Symmetry and Chirality!
v Compounds containing more than one chirality will be chiral: not always true!!!
!
Are they chiral?!
!
chiral! achiral!
Symmetry and Chirality!
v Compounds containing more than one chirality will be chiral: not always true!!!
!
Are they chiral?!
!
chiral! achiral!
Rotational and Reflectional Symmetry!
v Rotational symmetry: an axis of symmetry (Cn) !
(e.g. trans-1,2-dimethylcyclohexane) ; for 90° = C2!
v Reflectional symmetry: a plane of symmetry (σ) !
(e.g. cis-1,2-dimethylcyclohexane)!
!
v Rotational symmetry: an axis of symmetry (Cn) !
(e.g. trans-1,2-dimethylcyclohexane) ; for 90° = C2!
v Reflectional symmetry: a plane of symmetry (σ) !
(e.g. cis-1,2-dimethylcyclohexane)!
!
Rotational and Reflectional Symmetry!
16!
v Rotational symmetry: an axis of symmetry (Cn) !
(e.g. trans-1,2-dimethylcyclohexane) ; for 90° = C2!
v Reflectional symmetry: a plane of symmetry (σ) !
(e.g. cis-1,2-dimethylcyclohexane)!
!
Rotational and Reflectional Symmetry! Symmetry and Chirality!
v Compounds containing more than one chirality will be chiral: not always true!!!
!
Why???!!
chiral! achiral!
Rotational and Reflectional Symmetry!
v Rotational symmetry: an axis of symmetry!
– Chirality is not dependent in any way on rotational symmetry.!
v Reflectional symmetry: a plane of symmetry!
– Any compound that possesses a plane of symmetry in any conformation will be achiral.!
!
!
vs.!
Rotational and Reflectional Symmetry!
v Rotational symmetry: an axis of symmetry!
– Chirality is not dependent in any way on rotational symmetry.!
v Reflectional symmetry: a plane of symmetry!
– Any compound that possesses a plane of symmetry in any conformation will be achiral.!
!
!
vs.!
identical"
Rotational and Reflectional Symmetry!
v Compounds containing more than one chirality will be chiral: not always true!!!
!
Are they chiral?!
!
chiral! achiral!
Bonus – Additional Reflectional Symmetry: A Center of Inversion!
v Reflectional symmetry!
– a plane of symmetry (σ) ! – a center of symmetry or inversion center (i)!
!Is this compound chiral?!
NNO
O•
17!
Bonus – Additional Reflectional Symmetry: A Center of Inversion!
v Reflectional symmetry!
– a plane of symmetry (σ) ! – a center of symmetry or inversion center (i)!
!Is this compound chiral?!
NNO
O•
Bonus – Additional Reflectional Symmetry: A Center of Inversion!
v Reflectional symmetry!
– a plane of symmetry (σ) ! – a center of symmetry or inversion center (i)!
!Is this compound chiral? !
In fact, no plane of symmetry exists. Then chiral?!
NNO
O•
Bonus – Additional Reflectional Symmetry: A Center of Inversion!
v Reflectional symmetry!
– a plane of symmetry (σ) ! – a center of symmetry or inversion center (i)!
!Is this compound chiral? But, a center of symmetry (inversion center, one type of
reflectional symmetry) exists. Therefore, achiral!
NNO
O•
Meso Compounds!
Meso compounds: possessing reflectional symmetry (a plane of symmetry)!
– achiral.!!
How many stereoisomers?!
OHOH
Meso Compounds!
Meso compounds: possessing reflectional symmetry (a plane of symmetry)!
– achiral.!!
How many stereoisomers? 22 = 4 ??!
OHOH
Meso Compounds!
Meso compounds: possessing reflectional symmetry (a plane of symmetry)!
– achiral.!!
How many stereoisomers? 22 = 4 ??!
!
18!
Meso Compounds!
Meso compounds: possessing reflectional symmetry (a plane of symmetry)!
– achiral.!!
How many stereoisomers? 22 = 4 ??!
!
Meso Compounds!
Meso compounds: possessing reflectional symmetry (a plane of symmetry)!
– achiral.!!
How many stereoisomers? 22 = 4 ??!
!
meso compound"
5.7 Fischer Projections!
Useful for a stereochemistry in “sugars” !
!
Fischer Projections!
Configuration ? !
!
Fischer Projections! 5.8 Conformationally Mobile Acyclic System!
v Two conformations (butane) are nonsuperimposible mirror images: Enantiomers!
v Butane in two conformations is not enantiomers!!!!
– constantly interconverting via single-bond rotation (which occurs with a very low energy barrier)!
v If the fast conformational interconversion can be prevented, two conformational isomers can be enantiomeric. How? extremely low temperature!
!
19!
Conformationally Mobile Acyclic System!
v Two conformations (butane) are nonsuperimposible mirror images: Enantiomers!
v Butane in two conformations is not enantiomers!!! (no chiral compounds, i.e. optically inactive) – constantly interconverting via single-bond rotation (which occurs with a very low energy barrier)!
v If the fast conformational interconversion can be prevented, two conformational isomers can be enantiomeric. How? extremely low temperature!
!
v Two conformations (butane) are nonsuperimposible mirror images: Enantiomers!
v Butane in two conformations is not enantiomers!!! (no chiral compounds, i.e. optically inactive) – constantly interconverting via single-bond rotation (which occurs with a very low energy barrier)!
v If the fast conformational interconversion can be prevented, two conformational isomers can be enantiomeric. Any idea? !
Conformationally Mobile Acyclic System!
v Two conformations (butane) are nonsuperimposible mirror images: Enantiomers!
v Butane in two conformations is not enantiomers!!! (no chiral compounds, i.e. optically inactive) – constantly interconverting via single-bond rotation (which occurs with a very low energy barrier)!
v If the fast conformational interconversion can be prevented, two conformational isomers can be enantiomeric. Any idea? at extremely low temperature!
Conformationally Mobile Acyclic System! Conformationally Mobile Cyclic System!
cis-1,2-Dimethylcyclohexane!
v Nonsuperimposible mirror image: enantiomeric?!
v This compound is, however, optically inactive, because the conformations rapidly interconvert at room temperature.!
! !
Conformationally Mobile Cyclic System!
cis-1,2-Dimethylcyclohexane!
v Nonsuperimposible mirror image: enantiomeric?!
v This compound is, however, optically inactive, because the conformations rapidly interconvert at room temperature.!
! !
Conformationally Mobile Cyclic System!
cis-1,2-Dimethylcyclohexane!
v Nonsuperimposible mirror image: enantiomeric?!
v This compound is, however, optically inactive, because the conformations rapidly interconvert at room temperature.!
! !
20!
Conformationally Mobile Cyclic System!
cis-1,2-Dimethylcyclohexane!
v Nonsuperimposible mirror image: enantiomeric?!
v This compound is, however, optically inactive, because the conformations rapidly interconvert at room temperature.!
v Meso compound!! !
5.9 Resolution of Enantiomers!
Enantiomers: Identical physical properties (e.g. meting point, boiling point…)!
How can we separate them?!
! !
Resolution of Enantiomers: Crystallization!
Enantiomers: Identical physical properties (e.g. meting point, boiling point…)!
How can we separate them?!
1. Resolution via Crystallization!
– Pasteur: understood two distinct shapes of crystals (e.g., a racemic mixture of tartrate: not general)!
! !
Resolution of Enantiomers: Resolution!
Enantiomers: Identical physical properties (e.g. meting point, boiling point…)!
How can we separate them?!
1. Resolution via Crystallization!
2. Resolution: A simple idea is that diastereomers have different physical properties: temporarily generating diastereomers from enantiomers using a resolving agent!
!
Resolution of Enantiomers: Resolution!
Enantiomers: Identical physical properties (e.g. meting point, boiling point…)!
How can we separate them?!
2. Resolution: A simple idea is that diastereomers have different physical properties: temporarily generating diastereomers from enantiomers using a resolving agent!
!
Resolution of Enantiomers: Chiral Column Chromatography!
Enantiomers: Identical physical properties (e.g. meting point, boiling point…)!
How can we separate them?!
1. Resolution via Crystallization!
2. Resolution: A simple idea is that diastereomers have different physical properties: temporarily generating diastereomers from enantiomers using a resolving agent!
3. Chiral column Chromatography: using a chiral absorbent that interacts with each enantiomers differently!
!