Chapter 5.7, Problem 27ATS

(a)

Interpretation Introduction

Interpretation:

The configuration for every chiral center in the given compounds has to be determined.

Concept introduction:

The stereoisomerism is the arrangement of atoms in molecules whose connectivity remains the same but their arrangement in different in each isomer.

Chiral centre: A chiral centre is defined as the tetrahedral carbon atom in an organic molecule that is connected to four non-identical groups/substituents. It is sometimes known as a stereo genic centre.

Chirality: The geometric property of molecules where the structure of the molecule and its mirror image are not superimposable is known as chirality. Chiral molecules are optically active and they can rotate the plane polarized light.

R and S nomenclature: it is used to assign the molecule using CIP (Cahn-Ingold-Prelog) rules.

The CIP rules are as follows:

Select the chiral carbon and assign the numbers according to the decreasing atomic mass of atoms attached to it.

If the numbering follows clockwise direction then the molecule is termed as R and if it follows anti-clockwise direction then molecule is termed as S.

(b)

Interpretation Introduction

Interpretation:

The realationship between compound 1 and compound 2 has to be determined.

Concept introduction:

The stereoisomerism is the arrangement of atoms in molecules whose connectivity remains the same but their arrangement in different in each isomer.

Chiral centre: A chiral centre is defined as the tetrahedral carbon atom in an organic molecule that is connected to four non-identical groups/substituents. It is sometimes known as a stereo genic centre.

Chirality: The geometric property of molecules where the structure of the molecule and its mirror image are not superimposable is known as chirality. Chiral molecules are optically active and they can rotate the plane polarized light.

Enantiomers: These are stereoisomers that are not superimposable mirror images of each other and the configurations at all stereo genic centers are exactly opposite.

Diastereomers: These are stereoisomers that are not enantiomers of one another. They have different physical properties so that they are viewed as different chemical substances.

(c)

Interpretation Introduction

Interpretation:

Using dashes and wedges bond line structures of compound 1 and 2 has to be drawn.

Concept introduction:

From the angle of observer the front carbon is proximal and second carbon is distal.

In wedge-dash line representation wedge is coming out of the plane and going behind the plane, the wedge and the dash of front carbon in Newman projection are pointing up and the wedge and the dash of back carbon in Newman projection are pointing down.