organic question!

[SpikeyMike83]

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Lets see if attaching this works. It should open in paint.

This came from the ACS Organic Chemistry Guide.

The answer should be B, but why???

 

[herpecin]

because all of the other molecules are meso compounds. any way you fold them in half, they are exactly the same on the other side...except for B, and only because the 2 OH groups are trans. If they were cis, it too would be a meso compound.

 

[SpikeyMike83]

what about D though? the substituents are trans there as well. I understand that A and C were meso, but I couldn't figure out why B over D.

 

[Natatiap]

The answer is B. Not only because some of the other answers are meso but they are achiral. there is no chiral center in the others because the OH is attatched to TWO -CH2 groups and therefore does not have four non-identical groups so it cannot be chiral.

 

[Manyak222]

is superposibility a word? If it is, put me down for 10 superposibilities..

 

[RockstarDMD]

what about D though? the substituents are trans there as well. I understand that A and C were meso, but I couldn't figure out why B over D.

Put B and D in chair conformations and compare the two this should answer your question. 👍

 

[jkh1886]

draw out the chair cyclohexane for D. then, you'll see why it's meso. it's teh ax/ax, or eq/eq conformation on opposite carbons, rather than on adjacent carbons.

 

[SpikeyMike83]

oh, duh!

thanks everyone. i think maybe my brain is just fried... oh well... back to the books. i've got 10 days