Chapter 4.16, Problem 63P

Interpretation Introduction

Interpretation:

The reason why the given compound A has two stereoisomers and compound B, C exist as single compound has to be explained.

Concept introduction:

Stereoisomers are isomers which have different spatial arrangement in spite of same bond connectivity. Stereoisomers are due to the presence of stereocenter.  Stereocenter may be an atom axis (bond) or plane from which interchanging of two groups leads to stereoisomers.

Asymmetric center is a stereocenter which arises to a compound if any atom is bonded to four different groups.

If one of the four groups attached to nitrogen is lone pair, then inversion of amine takes place. So stereoisomers will not exist.

The equation for finding Stereoisomers from number of asymmetric centers in compounds is $2^n$, in which ‘n’ is the number of asymmetric centers.