Mirror symmetry in Fischer Projection

[keikoblue2]

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Hi all,

For a molecule like this, where you have three chiral centers (on carbons 2,3,4) and the OH on those carbons point left, there would be mirror symmetry if you slash across carbon 3.
..........CH2OH
OH-----C-----H
OH-----C-----H
OH-----C-----H
..........CH2OH


What if the middle OH on carbon 3 was on the right, instead (shown below)? Would there still be mirror symmetry if you slash across carbon 3, because the OH on carbons 2 and 4 still mirrors each other?
..........CH2OH
OH-----C-----H
...H-----C-----OH
OH-----C-----H
..........CH2OH

So basically, if both these compounds have mirror symmetry, they're both meso, and are optically inactive? Thanks!

 

[FeinMS]

No COOH and CH2OH are not the same

 

[keikoblue2]

No COOH and CH2OH are not the same

Oops you're right, there was an extra reduction step. Let's say The groups on C1 and C5 are the same, would the two structures both have mirror symmetry, then? I edited it now, thanks!

 

[FeinMS]

It's okay. I remember my gen chem professor making the same mistake. Yup both will have mirror symmetry and are meso.