Orgoman Question

[Ibraiz]

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Why is answer choice D has an enantiomer? Even though it has two chiral center. I was thinking for answer choice D is wrong b/c it would be a meso compound but the explanation states that it has only one enantiomer. Is it not a meso compound as it has a symmetry?

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[Cool Beans]

Note that in answer choice D the Br atoms are trans to each other and therefore there is no mirror plane of symmetry. They would have to be cis to have an internal mirror plane of symmetry. This compound is definitely chiral and has an enantiomer.

 

[Ibraiz]

I came across another problem and I just realized that. But I have another question. Is it possible for both the Br to be added cis or trans so it would become a meso compound?

 

[Vinden]

I came across another problem and I just realized that. But I have another question. Is it possible for both the Br to be added cis or trans so it would become a meso compound?

No, it's impossible. Addition of Br2 and an alken is an anti-addition.