Orgo Question (Chad's quiz)

[hope_to_match]

My question is: about substituting Cl at C-2 and leading to 2 stereoisomers..Why are there 2 stereoisomers? I thought it's the same compound therefore the total products formed are only 3.

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[Glimmer1991]

Granted, it's been a long time since I've been in orgo, so I might be wrong... but wouldn't one be an R- compound and the other one be an S- compound? They're different.

 

[hope_to_match]

I understand that one is R and one is S

I guess I am confused because if we rotate the bond or flip the molecule they will be the same products..

 

[Magwar]

Substitution @ C1 forms an achiral center = 1 Product
Substitution @ C4 forms an achiral center = 1 Product

Substitution @ C2 forms a chiral center (C bonded to Cl, methyl group, 5C group, and H) = 2 Products -- the R and S enantiomer. No matter how you turn the molecules they are not superimposable. In the pictures at the bottom of the solution look at the groups about the chiral carbon and assign priorities. The one on the left is the S enantiomer, the one on the right is the R enantiomer.

 

[Glimmer1991]

You have Chad, right? I think it'd be a great idea to go and rewatch his videos about this--this is sort of one of those "key," basic concepts that they are sure to throw at you on the DAT. It's always good to have a little refresher!

 

[woodloga]

Do you have a model kit? I remember building a few structures helped me when I took the class. Once you build a molecule or two it'll click.

Good luck!

 

[Faux]

I understand that one is R and one is S

I guess I am confused because if we rotate the bond or flip the molecule they will be the same products..

It won't be the same product because theres no symmetry in this case once you add the Cl to carbon 2.

Draw both pictures, are you sure they are both the same products if one is a wedge and another is a dash?

 

[hope_to_match]

ohhhh i see it now! thanks for all of your replies!