Why are these compounds not an enantiomer?

[dentalgirlyay]

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__CH3
H------Br
H------Br
__CH3

__CH3
Br------H
Br------H
__CH3

How are the two compounds not an enantiomer? If they do not give u meso compound as a choice. In the kaplan explanation it says that it is not an enantiomer because the two compounds are superimposable. but to me i feel like they are not superimposable and are mirror images of each other. 😕

 

[Andre3k]

They are superimposable, take one and flip it upside down and they are identical.

__CH3
H------Br
H------Br
__CH3

__CH3
H------Br
H------Br
__CH3
(upside down)

 

[dentalgirlyay]

So we can flip compounds? or does this only work w/ enantiomer?

 

[Isradoc1983]

these are meso compounds

 

[ucla2134]

__CH3
H------Br
H------Br
__CH3

__CH3
Br------H
Br------H
__CH3

How are the two compounds not an enantiomer? If they do not give u meso compound as a choice. In the kaplan explanation it says that it is not an enantiomer because the two compounds are superimposable. but to me i feel like they are not superimposable and are mirror images of each other. 😕

Yes, they are meso compound since there are line of symmetry there. If one of the 2 methyl was replaced by ethyl, for instance, then the line of symmetry disappear. At that point, YES--> you have an enantiomer.

 

[Versati1ity]

They are identical, not meso. You can flip fischer projections 180* to compare.