ACS Question: Stereochemistry and Chair Conformations #acs

Added: 2026-05-17

[00:00:01]draw out the configurations for each. So if I'm looking at this chyal center, I would I'm going to show the hydrogen that's also there. Assigning priority, I'm looking at this methyl, this CH2, and this CH. I want the one with the least amount of hydrogens. That's going to be the highest priority. So this is priority 1, 2, 3, and then four.

[00:00:30]drawing that arrow. I'm going towards the right, but it's not R because this is wedge. So that's S. I'll do the same thing for this chyro center. Drawing out the hydrogen that is dashed. That's helpful. I know that this again is going to be one because this is AC versus AC2.

[00:00:52]I want the one with the least amount of hydrogens. That's the higher priority.

[00:00:56]This is two. This is three. This is four.

[00:01:00]Drawing our curved arrow. This is going towards the left. That is what it's going to be.

[00:01:07]So, it's S. Do the same thing for these others.

[00:01:11]Drawing in that hydrogen. Again, this is priority group one, two, and three. Just like we've seen before, and four. This is connecting it 1 2 and three. It's going towards the right. This is dash.

[00:01:26]So, that's fine. And this is R. Now we'll do the next chyal center. Draw in the wedged hydrogen. This would have been carbon one, the priority group one.

[00:01:35]And this priority group 2, three and four. This is one and two and three connecting that. That's going towards the left. However, it's wedged. So that must be the opposite. It's not S, it's R. Because all of our configurations have changed. That must mean they're animer.

[00:01:56]D is our answer. Remember with diysterimer only one of the chyro centers changes its configuration.

[00:02:03]For an antimemurs all of the configurations must change.

[00:02:09]Another way that you could have seen this these are literally mirror images of each other. This really just flipped opposite sides. Like think of this as kind of just flipping over. So yes, those are anantimer. Will it always be that easy? No, it will not. And sometimes you might not be able to spot that automatically. So I at least wanted to give you something to be able to figure it out. I know that it does take a little bit more time, but if you wouldn't have spotted that these were mirror images, your next line of defense is figuring out the configurations.