Chapter 5, Problem 69P

Interpretation Introduction

(a)

Interpretation: The number of stereogenic centers in the given compound is to be predicted. The maximum number of possible stereoisomers is to be predicted.

Concept introduction: An atom bearing four different atoms or groups which produces stereoisomers on interchange of any two groups are stereogenic centers.

Interpretation Introduction

(b)

Interpretation: Both enantiomers of mandelic acid is to be drawn and stereogenic center is to be labeled as $R$ or $S$.

Concept introduction: The stereogenic centers with $R,S$ configuration are assigned according to Cahn-Ingold-Prelog rules. According to these rules, the substituents attached to stereogenic centers are given priority. On moving from higher priority to lower priority substituent in clockwise direction, the compound is assigned with $R$ configuration. On moving from higher priority to lower priority substituent in anticlockwise direction, the compound is assigned with $S$ configuration.

Interpretation Introduction

(c)

Interpretation: The $\left[\alpha \right]$ value for the given solution is to be calculated.

Concept introduction: Enantiomeric excess is the excess of major enantiomer over the minor enantiomer. Enantiomeric excess is equivalent to the optical purity. Enantiomeric excess is the fraction of observed rotation of the mixture to specific rotation of the pure enantiomer

Interpretation Introduction

(d)

Interpretation: Enantiomeric excess of the given solution is to be calculated. The percentage of each enantiomer present is to be calculated.

Concept introduction: Enantiomeric excess is the excess of major enantiomer over the minor enantiomer. Enantiomeric excess is equivalent to the optical purity. Enantiomeric excess is the fraction of observed rotation of the mixture to specific rotation of the pure enantiomer.