Chapter 6, Problem 78P

Interpretation Introduction

Interpretation:

The stereoisomer required to obtain a $\text{meso}$ compound in presence of $B{r}_2$ should be determined.

Concept introduction:

Addition Reaction: It is defined as chemical reaction in which two given molecules combines and forms product. The types of addition reactions are electrophilic addition, nucleophilic addition, free radical additions and cycloadditions. Generally, compounds with carbon-hetero atom bonds favors addition reaction.

In addition reaction of alkenes when two substituents are placed on same side of $C=C$ then it is named as $syn$ addition if it is placed on opposite sides of $C=C$ it is defined as anti-addition.

Stereoisomers: Two compounds with same molecular formula but different in their orientation are considered as isomers.

The presence of atom with non-super impossible mirror image is defined as enantiomers which are given $\text{R and S}$ configuration based on the atoms bonded with them.

Meso compound: The compound with chiral carbon that also have plane of symmetry which actually makes the compound achiral that does not have an enantiomer (Non-superimposable mirror images).

R and S nomenclature: it is used to assign the molecule using CIP 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.