2. Enantiomers

3. Enantiomers
Glyceraldehydes are not supper
impossible on its mirror image has chiral
center and therefore exist as two
different enantiomers with opposite
optical rotation.

4. R/S rotation

The right hand left hand nomenclature is
used to name the enantiomers of chiral
compounds. The sterocenters are labeled
as R or S.
R- Glyceraldehyde
S-Glyceraldehyde

5. Chirality

In compounds in which an atom that is
connected to 4 different substituent groups.
This atom is called a-symmetric atom or a
stereo center. Those compounds are called
chiral compounds.
Chiral Center

6. Optical Activity
The interaction with light is called optical
activity and enantiomers are often called
optical isomers.
 Optical rotation is measured with the
polarimeter.


7. Block diagram
Anti-clock
wise
rotation
(-)(l)
When plane
polarized light
Fall sample
of
enantiomers
Rotate the
light
Clockwise
dextrorotatry
(+)(d)

8. Racemic Mixture

It is a mixture of equal amount of (+)
and (-) enantiomers of chiral
compounds.

It shows no net rotation of plane
polarized light.

9. Racemization

When one enantiomers equilibrates with
its mirror image the process is called is
recemization.
50% +
50%-

11. Representation:
•“andiron” or “sawhorse ”
Newman projections:

12. Fisher Projection
It is a formula which represent tetrahedral
carbon atom and their substituent's in two
dimensions. The molecule is drawn in the
form of cross.
 The tetrahedral carbon is the plane of the
paper at the center of cross.
 Atoms connected to the tetrahedral carbon
by horizontal bonds are behind the plane of
the paper.
 Atoms connected to the tetrahedral carbon
by vertical bonds in front of the plane of the
paper.


13. Conti……

Fisher projection tell us the absolute
configuration then we get R and S
enantiomers.

14. Resolution
Pure enantiomers can be synthesizing
racemic mixture and then separating the
enantiomers Formed by a process
called resolution.
 Glyceraldehydes are separated by
chemical method in compound COOH
must be present in compound does not
contain COOH acid. first it changed into
carboxylic acid then react with
L-brucine.
