Is the middle carbon chiral in this molecule?

[FROGGBUSTER]

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[vayntraubinator]

nope

 

[FROGGBUSTER]

nope

Okay that's what I thought. Can you check my reasoning please?

The definition of chirality is non-superimposable mirror images. Even though this molecule is not meso, one of the substituents off the middle carbon is R & one is S. This means the enantiomer would just simply be opposite. R turns into S, and S turns into R.

But this is the same molecule as before and super-imposable. Thus, the carbon is not chiral

Is this correct?

 

[BeatMCAT]

nope. there are only three diff things attached to the middle carbon in this molecule. there needs to be four for a molecule to be chiral

 

[exquisitemelody]

Okay that's what I thought. Can you check my reasoning please?

The definition of chirality is non-superimposable mirror images. Even though this molecule is not meso, one of the substituents off the middle carbon is R & one is S. This means the enantiomer would just simply be opposite. R turns into S, and S turns into R.

But this is the same molecule as before and super-imposable. Thus, the carbon is not chiral

Is this correct?

I'm not really understanding what you're saying but....

The definition of chirality is having 4 different substituents. Non-superimposable mirror images are enantiomers (not necessarily the definition of chirality). In terms of chirality, enantiomers have opposite chirality at every chiral carbon. (I believe that's what you're describing when you say R turns to S and S turns to R).

The reason why that carbon is not chiral is because it only has 3 different substituents - OH, H, and HCOOHBr.

 

[FROGGBUSTER]

I'm not really understanding what you're saying but....

The definition of chirality is having 4 different substituents. Non-superimposable mirror images are enantiomers (not necessarily the definition of chirality). In terms of chirality, enantiomers have opposite chirality at every chiral carbon. (I believe that's what you're describing when you say R turns to S and S turns to R).

The reason why that carbon is not chiral is because it only has 3 different substituents - OH, H, and HCOOHBr.

Hm, well I wasn't sure if those 2 substituents actually counted as the same thing since they have different stereochemistries around their chiral centers (one is R & the other is S). I actually don't think they should because if you had two structurally different isomers attached to the middle carbon, it wouldn't be considered the same.

 

[salim271]

The substituents are technically the same, but spatially they're different, and have different stereochemistries... the molecule doesnt have symmetry at the middle carbon, that isnt enough to make it chiral? I thought arrangements of atoms in space are enough to make things with the same molecular formula act as completely different molecules. Isnt that the basis of stereochemistry?

Confused 🙁 this is my worst organic subject.

 

[exquisitemelody]

OP, is the correct answer yes or no? (if it's chiral or not)

 

[Axon hillock]

OP, is the correct answer yes or no? (if it's chiral or not)

It's not chiral.

 

[MShopes]

Chiral molecules don't require the molecule to be an enantiomer while an enantiomer requires a molecule to be chiral....so chirality depends only on having 4 different molecules around the carbon....it doesn't have to do with R or S...but enantiomer require a chiral carbon as well as no symmetry (therefore no meso compound)...that is why enantiomers are mirror images of each other (i.e one is R and the other is S)

So, no this carbon is not chiral.

 

[FROGGBUSTER]

OP, is the correct answer yes or no? (if it's chiral or not)

i don't know, i made it up.

but it should be no.

 

[ih2183]

Hope this is clear: if this is your molecule, reflect it over a mirror plane, and see if the orientation of the image in space is superimposable to your molecule. Since the steriochemistry of the other centers may be R or S, this orientation is switched when mirrored on the plane. But don't let this fool you because the molecule can still be superimposable if you rotate it 180 degrees. It is in fact the same molecule.

Another way to look at this is rotation around the C-C bond such that you can fold the molecule in half horizontally and have symmetry.

 

[ih2183]