Are These Enantiomers, Diastereomers or Identical Molecules ? (STEREOCHEMISTRY) 

how did you do?

I saw that too

Same , the last part is so lit!

You're so welcome!

Gotchu Ruohan!

Hey mark, you are doing something wrong. Starting with the molecule on the left, counting in a clock wise fashion, on carbon 1, the chlorine is going down, on carbon 5 the bromine is going up. Switch to the molecule on the right, REMEMBER when you do the flip, the carbon with the chlorine is now your carbon 1. So on carbon I see the chlorine going down. counting ANTI-CLOCKWISE this time since its a flip, the bromine on carbon five is going up. draw the cyclic structures for both and they are the same.

If you build the molecules for the first two, you will see that there is no way possible for those to be identical, unless you perform surgery on the molecule and move the atoms to inverted positions, which makes it a constitutional isomer, not identical. The only way to make those identical is to switch positions

I also am confused. I worked it out and got enantiomers

no as i thing, you are to be right because, you have an effort for reach your goal.

The way you have numbered the first two conformations is incorrect. It has to be the lowest number. For instance, you've counted 1-3 instead of 1-5. That's why people were confused. Thanks for the vid though.

Hey Mohit, that's a great question. Lets take a look at the one on the left first. Looking at the chiral carbon with the -CH3 having a wedge. The carbon has a (CH3), a Hydrogen. Now look, if I step 1 carbon away from each sides, I hit a CH2 which we cannot make any conclusion that they are different THINGS since they are both CH2'S. With that being said, we have to go another carbon out on both sides. When this happens, a CHLORINE atom is clearly present on one side, while i still have another CH2 on the other side. This is why the carbon is chiral because it has 4 DIFFERENT SUBSTIUENTS BONDED to it. It has a Hydrogen, A Ch3, a CH2CHCL, and a CH2CH2. This is also true for the other chiral center. Hope this clarifies everything.

Okay, that makes sense, now, suppose if we have para- Xylene (1,4-dimethylbenzene), then, by this rule this compound must not have any chiral centre, while if it were meta xylene it must have 2 chiral centres, right?

No, that is incorrect. Again, when we talk about chirality and an atom being chiral, 4 DIFFERENT THINGS has to be bonded to the atom itself. In the benzene ring, it is conjugated, meaning, we have double bonds. This means at any given time, I can only have three different things bonded to one of those carbons. In this case, none of them would have chiral centers. Always remember, 4 DIFFERENT THINGS MUST BE BONDED, NOT 3 like in this case or two or one. It must be FOUR. Good question again.

Oh sorry, i forgot that those carbon in ring are sp2 hybrid, so, the same question now turns to 1,4-dimethylcyclohexane must not have chiral carbons, whereas 1,3-dimethylcyclohexane must possess 2 chiral carbons. Is this true? Or am I again missing out on something?

Yes, this assumption is true.

gotcha!

Wait I think I got it now but please if my explanation is wrong please feel free to correct me. I think we said 1 kept same 1 changes, when “flipping” “inverting” it creates a stereoisomer because in such case there will always be a different 3D arrangement. Since (1 kept same 1 changes). So that’s what makes it a steroisomer Or i think I am confusing what a stereoisomer is with a diastereoisomer. Please help I think I am just digging a rabbit hole 😶

gotcha!

theyre enantiomers right

I gotchu 😉

@@KevanScience do you think you could do an example video on a big chiral compound like estrogen for identifying R/S? I had a quiz on one and it took me too long to work it out and I want to learn shortcuts to be more efficient identifying stereo centers and assigning R and S to each center.

@@daniellai7601 sure, look for that video in about 5 hours later tonight

@@KevanScience you’re the absolute best thank you! I’ll put my notifications on for your channel

No problem.

though the numbering is wrong, it doesn't create a change!