5. Chirality

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

(a)

A molecule of the type shown is discussed in greater detail in Section 6.5.1. Although it contains at least one atom with four different groups attached, why is it not a chiral molecule?

Which of the following compounds are meso?

(a)

For each compound, determine whether the molecule has an internal mirror plane of symmetry. If it does, draw the mirror plane on a three-dimensional drawing of the molecule. If the molecule does not have an internal mirror plane, determine whether the structure is chiral.

(a) methane

(b) cis-1,2-dibromocyclobutane

(c) trans-1,2-dibromocyclobutane

Which of the following has an achiral stereoisomer?

e. 1,3-dibromocyclobutane

f. 2,4-dibromopentane

Which of the following compounds are meso?

(c)

Which of the following has an achiral stereoisomer?

i. 1,2-dimethylcyclopentane

j, 1,2-dimethylcyclobutane

For each compound, determine whether the molecule has an internal mirror plane of symmetry. If it does, draw the mirror plane on a three-dimensional drawing of the molecule. If the molecule does not have an internal mirror plane, determine whether the structure is chiral.

(d) 1,2-dichloropropane

(e)

Which of the following compounds has a stereoisomer that is a meso compound?

e. 1,4-dichlorocyclohexane

f. 1,2-dichlorocyclobutane