Draw a three-dimensional structure for each compound, and star all asymmetric carbon atoms. Draw the mirror for each structure, and state whether you have drawn a pair of enantiomers or just the same molecule twice. Build molecular models of any of these examples that seem difficult to you
(a)
(b)

For each of the following chiral molecules, obtain the enantiomer (i) by drawing the nonsuperimposable mirror image and (ii) by switching the spatial orientation at each asymmetric center. Confirm (possibly using models) that the structures you drew for (i) and (ii) are the same.

(d)

For many centuries, the Chinese have used extracts from a group of herbs known as ephedra to treat asthma. A compound named ephedrine has been isolated from these herbs and found to be a potent dilator of air passages in the lungs.

a. How many stereoisomers does ephedrine have?

b. The stereoisomer shown here is the one that is pharmacologically active. What is the configuration of each of the asymmetric centers?

How many stereoisomers are possible for each of the following molecules?

(a)

How many stereoisomers are possible for each of the following molecules?

(c)

Draw the stereoisomers of the following amino acids. Indicate pairs of enantiomers and pairs of diastereomers.

a.

Which of the following pairs of compounds could be separated by recrystallization or distillation?

a. meso-tartaric acid and (±)-tartaric acid (HOOC—CHOH—CHOH—COOH)

Draw the enantiomer, if any, for each structure.

(e)

(f)

1-Bromo-2-methylcyclopentane has four pairs of diastereomers. Draw the four pairs.