Question

For each pair, give the relationship between the two compounds. Making models will be helpful.
(a) (2R, 3S)-2, 3-dibromohexane and (2S, 3R)-2, 3-dibromohexane
(b) (2R, 3S)-2, 3-dibromohexane and (2R, 3R)-2, 3-dibromohexane

Answer 1

Answer:

(a) Enantiomers

(b) Diastereomers

Explanation:

In the first pair of molecules, we have an opposite configuration. That is, in the first molecule we have an R and S configuration and in the second an S and R configuration. Therefore we have a mirror image, if this is true, we will have a mirror image and we will have "enantiomers". (See figure 1)

In the second pair of molecules, we do not have a mirror image. Since the first molecule has an R, S configuration (the mirror image would be S, R). In the second molecule, we have an R, R configuration (the mirror image would be S, S). Therefore, the relationship between these molecules is "diastereoisomers". (See figure 2)