IN THE NAME OF ALLAH, THE MOST BENEFICENT

AND MERCIFUL

Enantiomers

Enantiomers

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

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

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

Optical Activity

The interaction with light is called optical activity and enantiomers are often called optical isomers.

Optical rotation is measured with the polarimeter.

Block diagram

When plane polarized light

Fall sample of

enantiomers

Rotate the light

Anti-clock wise

rotation(-)(l)

Clockwise dextrorotatry

(+)(d)

Racemic Mixture

It is a mixture of equal amount of (+) and (-) enantiomers of chiral compounds.

It shows no net rotation of plane polarized light.

Racemization

When one enantiomers equilibrates with its mirror image the process is called is recemization.

50% + 50%-

Representation:•“andiron” or “sawhorse ”

Newman projections:

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.

Conti……

Fisher projection tell us the absolute configuration then we get R and S enantiomers.

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.