[G O D I V A]

Which of the following are conformational isomers? (number them 1,2,3,4 starting from the left)

Is it 3 and 4?

[Suprachiasmatic Nucleus]

Which of the following are conformational isomers? (number them 1,2,3,4 starting from the left)

Is it 3 and 4?

Hi, I believe it is #2 and #4, by rotating the sigma bonds.

#2 is: R,R.
#4 is: R,R.

#1 is: S,R
#3 is: S,S; therefore it SHOULD be 2,4 if I am correct.

[G O D I V A]

Which of the following are conformational isomers? (number them 1,2,3,4 starting from the left)

Is it 3 and 4?

Hi, I believe it is #2 and #4, by rotating the sigma bonds.

#2 is: R,R.
#4 is: R,R.

#1 is: S,R
#3 is: S,S; therefore it SHOULD be 2,4 if I am correct.

I get something different for 2 and 4



For 2 I get S, R not R, R

and for 4, how do you know which way to go from the bromine?

[Mitsunobo]

When assigning R and S, it would be easier if you position the hydrogen at the back, then assign priorities to the remaining substituents. I think you will agree with the previous poster if you do that.

[G O D I V A]

Hi, I believe it is #2 and #4, by rotating the sigma bonds.

When assigning R and S, it would be easier if you position the hydrogen at the back, then assign priorities to the remaining substituents. I think you will agree with the previous poster if you do that.

Alright thanks guys.  I have a related question to this.  I'm horrible at this 3d rotation thing in my head.

If you reacted (E)-2-butene with Br₂ which of those (1-4) would you get?  I was thinking 3 only because it would be anti addition right?  So the bromine have to be like 180 apart so that excludes 1,2 and 4