5.3 Molecules with Multiple Chiral Centers | Enantiomers, Diastereomers, and Meso Compounds | OChem

Chad covers the possible relationships between the different stereoisomers that are possible in structures having multiple chiral centers. He starts by showing how to determine the number of possible stereoisomers based upon the number of chiral centers present. He then shows how to determine when two stereoisomers are enantiomers and when they are diastereomers.
He then introduces Meso compounds, compounds that are achiral even though they have chiral centers. He shows how an internal mirror plane (a sigma plane) is helpful in identifying achiral compounds and can be helpful in identifying Meso compounds as well. Chad concludes the lesson by showing how to identify Meso compounds even when they are drawn in rotational conformations that make it difficult to see the presence of sigma planes.
If you want all my study guides, quizzes, and practice exams, check out my premium course at www.chadsprep.com/organic-che...
00:00 Lesson Introduction
00:56 How to Determine the Number of Stereoisomers
03:44 Enantiomers and Diastereomers when there are Two Chiral Centers
11:05 Introduction to Meso Compounds
18:17 How to Identify Meso Compounds
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Пікірлер: 92

  • @marysharkoff2415
    @marysharkoff2415 Жыл бұрын

    This entire ochem series is so incredibly helpful. Thank you!

  • @ChadsPrep

    @ChadsPrep

    Жыл бұрын

    Glad to hear it's helping you out Mary!

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    @mountcarmel711625 күн бұрын

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  • @ChadsPrep

    @ChadsPrep

    24 күн бұрын

    Thank you

  • @tomasquintero4911
    @tomasquintero49113 жыл бұрын

    This video restored my hope in being able to understand stereochemistry. Thank you!

  • @ChadsPrep

    @ChadsPrep

    3 жыл бұрын

    You're very welcome Tomas! So much vocabulary in the chapter and then there are the ways we recognize the different isomeric relationships all of which can make it very complicated. Glad you found this helpful!

  • @kaushikumarihami1982
    @kaushikumarihami19822 жыл бұрын

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  • @oshinshukla8527
    @oshinshukla85273 жыл бұрын

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  • @ChadsPrep

    @ChadsPrep

    3 жыл бұрын

    Glad it was helpful, Oshin - thanks for your comment!

  • @Peegeewannabe
    @Peegeewannabe10 ай бұрын

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  • @ChadsPrep

    @ChadsPrep

    10 ай бұрын

    You are very welcome.

  • @jocelynekoudou5174
    @jocelynekoudou51742 жыл бұрын

    Another wonderful video! Seriously, thank you so much for all you do, you're actually making these concepts fun to learn!

  • @ChadsPrep

    @ChadsPrep

    2 жыл бұрын

    Glad to hear it, Jocelyn - Happy Studying!

  • @VerenaKing
    @VerenaKing2 жыл бұрын

    A perfect explanation! Thank you!

  • @ChadsPrep

    @ChadsPrep

    2 жыл бұрын

    You're welcome, Verena!

  • @SewueseVivian
    @SewueseVivian7 ай бұрын

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  • @ChadsPrep

    @ChadsPrep

    7 ай бұрын

    Glad to hear it - you're welcome and Thank You.

  • @idek652
    @idek6524 ай бұрын

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  • @ChadsPrep

    @ChadsPrep

    4 ай бұрын

    Thank you for such kind words - He does and hope the same for you!

  • @user-pj5bk7ds8u
    @user-pj5bk7ds8u3 ай бұрын

    Thank you for the explanation of "Meso" 👍 Enjoyable learning time 👍

  • @ChadsPrep

    @ChadsPrep

    3 ай бұрын

    You bet - glad it was!

  • @Jennifer-pi6ty
    @Jennifer-pi6ty3 ай бұрын

    Thank for taking the time do make this video!!! It helped so much😊

  • @ChadsPrep

    @ChadsPrep

    3 ай бұрын

    Very welcome!

  • @jessicaneamtu9053
    @jessicaneamtu90538 ай бұрын

    Thank you for such a good explanation!

  • @ChadsPrep

    @ChadsPrep

    8 ай бұрын

    You're welcome - Thanks!

  • @fereyal
    @fereyal9 ай бұрын

    I love these incredibly helpful videos... thank you so much Mr. Chad😁😁😍

  • @ChadsPrep

    @ChadsPrep

    9 ай бұрын

    You're welcome - Glad you do!

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    @ghazalmehrvarz50122 жыл бұрын

    I feel bad that I have missed your channel so far :( I coul've saved a ton of time and confidence.

  • @ChadsPrep

    @ChadsPrep

    2 жыл бұрын

    Glad you finally found us, Ghazal - hope it helps you now. Happy Studying!

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    @mahaalbreiki91988 ай бұрын

    Thank you so much!!!

  • @ChadsPrep

    @ChadsPrep

    8 ай бұрын

    You are most welcome.

  • @kassandracarrillo981
    @kassandracarrillo9814 ай бұрын

    Thank you Chad. I have been struggling by learning with just my professors lectures, and you have changed my life. You definitely accomplished your goal of making orgo chem enjoyable! it feels like a fun game now and just trying to understand its rules. Without you I wouldn't be where I am today. You are amazing!!! you inspire so many students to keep learning !

  • @ChadsPrep

    @ChadsPrep

    4 ай бұрын

    Glad the channel is helping!

  • @rebeccaobewu5980
    @rebeccaobewu5980 Жыл бұрын

    This was really helpful thanks 😊

  • @ChadsPrep

    @ChadsPrep

    Жыл бұрын

    Glad to hear it, Rebecca - you're welcome!

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    @_leonora_a64002 ай бұрын

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  • @ChadsPrep

    @ChadsPrep

    2 ай бұрын

    Glad you found us!

  • @suhaylakamarudheen704
    @suhaylakamarudheen70413 күн бұрын

    Hi Chad! Could you please explain why you flipped the molecule at 5:20 (the blue drawing)? Did you flip it, so we can see that they both have wedges (hence their enantiomers)? But the ones on the bottom are diasteriomers as they’re not superimposable images to the molecule? (Ie. they have one wedge and one dash) Thank you so much Chad. I’ve been watching your videos since I was in my first year of undergrad!!! My favourite channel on KZread!

  • @Bulayla1426
    @Bulayla1426Ай бұрын

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  • @ChadsPrep

    @ChadsPrep

    Ай бұрын

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    @karinaburgess39898 ай бұрын

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  • @ChadsPrep

    @ChadsPrep

    8 ай бұрын

    Great to hear - You're welcome x1000!

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    @moawiahalbasyoni6229 Жыл бұрын

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  • @ChadsPrep

    @ChadsPrep

    Жыл бұрын

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    @cfskotbk98238 ай бұрын

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  • @ChadsPrep

    @ChadsPrep

    8 ай бұрын

    Glad the channel is helping you!

  • @christophefreslon2488
    @christophefreslon24883 ай бұрын

    Thanks for this very eductionnal lesson...even if you speak really fast for a non-native speaker...but that's surely the testimony of your passion for chemistry :-) By the way, I like your tee-shirt, you can only be a good man with this 😀

  • @ChadsPrep

    @ChadsPrep

    3 ай бұрын

    Thank you for your kind words, and if my fast paced passion for chemistry gets too fast, slow down the playback speed under the settings. Happy Studying!

  • @Crazymachin3gun
    @Crazymachin3gun6 ай бұрын

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    @ChadsPrep

    6 ай бұрын

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    @catar5602 Жыл бұрын

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    @ChadsPrep

    Жыл бұрын

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    @MadunaTjeketsi Жыл бұрын

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  • @ChadsPrep

    @ChadsPrep

    Жыл бұрын

    Thank you.

  • @jibraankhan9667
    @jibraankhan96673 жыл бұрын

    Is blue structure of (2R,4S)-2-bromo-4-chloropentane identical to the structure with two hash bonds @ 5:40?

  • @bethanyharrison3310
    @bethanyharrison33108 ай бұрын

    Question for you sir: Imagine if we’d been looking at the mirror image (through the plane of the board) of the very last example (which was (2R,3S)-2-chloro-3-methylhexane just as a reminder). This would render the stereochemistry 2S and 3R. So my question is: do we now list these numerically or alphabetically in the name’s starting parenthetical? (I’m suspecting alphabetical since IUPAC loves the alphabet)

  • @MrYahya0101
    @MrYahya01012 жыл бұрын

    You said diastereomers are those that are not mirror images. Would that include the same molecule with a rotation around one of its bonds for example I think in cis trans diastereomers, there is only rotation and no inversion of configuration? What about the same molecule (no rotation, no inversion). Would that be its own diastereomer? Thank you.

  • @komalchahal9671
    @komalchahal96718 ай бұрын

    @15:12 isn’t the molecule on lower left side is R and S, when configurations are not matched?

  • @jaiagrawal9963
    @jaiagrawal9963 Жыл бұрын

    I have a doubt at 15:25 those two compounds are enantiomer even though they have a center of symmetry. Why?

  • @user-in6jz8ik6y
    @user-in6jz8ik6y5 ай бұрын

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  • @ChadsPrep

    @ChadsPrep

    5 ай бұрын

    Glad the channel is helping you.

  • @radicalpisces
    @radicalpisces8 ай бұрын

    why are the R AND R for bromine and S and S still enantiomers?

  • @user-uu2st6pj3l
    @user-uu2st6pj3l2 ай бұрын

    Goat

  • @ChadsPrep

    @ChadsPrep

    2 ай бұрын

    Thank you

  • @shim525
    @shim525 Жыл бұрын

    Sir, I have a question for meso compounds. Cis-1,4-dichlorocyclohexane is a meso or not? It has two stereocenters in the molecule with a plane of symmetry and its mirror image is superimposable, but it does not have any chiral centers in the molecule. In this case, is it a meso or not?

  • @reydeleon4091

    @reydeleon4091

    Жыл бұрын

    For your question, it would just be achiral and optically inactive. For a meso compound, there must be both the presence of chiral centers and a plane of symmetry. In this case, there are no chiral centers to begin with so it is just achiral. Hopefully this answer helps.

  • @MrYahya0101
    @MrYahya01012 жыл бұрын

    Hey Chad, I assume when rotating the molecule around to see if it has a plane of symmetry, one shouldn't rotate in a way that changes the configuration right? Like, rotating around a chiral carbon may change the configuration and thus the R:S ratio of 1:1? Or does rotating around a bond typically not affect the configuration?

  • @ChadsPrep

    @ChadsPrep

    2 жыл бұрын

    Great question Youssef and your intuition at the end was correct! If you're just simply rotating around a bond then it won't change the configuration. Nice!

  • @MrYahya0101

    @MrYahya0101

    2 жыл бұрын

    @@ChadsPrep Thank you!

  • @ChadsPrep

    @ChadsPrep

    2 жыл бұрын

    @@MrYahya0101 You're welcome!

  • @benjaminhogan3157
    @benjaminhogan31573 жыл бұрын

    ***love*** better than like

  • @ChadsPrep

    @ChadsPrep

    3 жыл бұрын

    Thanks for the comment, Benjamin!

  • @MisterJ34
    @MisterJ349 ай бұрын

    can you explain at 23:33 when you did R&S how you found that, its tripping me up a little, please and thank you

  • @ChadsPrep

    @ChadsPrep

    9 ай бұрын

    No problem - so at this point we are looking at the left carbon with Br attached we assign priority based on atomic number so Br = 1, the top carbon is number 2 (because it is closer to the next Br atom than the bottom carbon, bottom carbon = 3 and the H = 4 if you trace with your finger or connect with a pen going from 1 -> 2 - > 3 you are moving clockwise or make in a 'right' (R) turn. So its R, the other carbon makes a left turn = S. Hope that helps!

  • @ChadsPrep

    @ChadsPrep

    9 ай бұрын

    check this video if you need a refresher on assigning R and S kzread.info/dash/bejne/oG2hubiGYLbOhM4.html

  • @MisterJ34

    @MisterJ34

    9 ай бұрын

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  • @ChadsPrep

    @ChadsPrep

    9 ай бұрын

    @@MisterJ34 Excellent and Kudos!

  • @Kenzo_254
    @Kenzo_254 Жыл бұрын

    When you talk about calculating number of stereisomers do you mean number of enantiomers? Because you have got me mixed up.

  • @johnscheller2697
    @johnscheller26972 жыл бұрын

    goat

  • @ChadsPrep

    @ChadsPrep

    2 жыл бұрын

    Thx!

  • @MrYahya0101
    @MrYahya01012 жыл бұрын

    If you have 3 chiral centers could that still be a meso compound?

  • @ChadsPrep

    @ChadsPrep

    2 жыл бұрын

    Yes! It has to have at least 2 and the most common examples you're likely to see have 2 chiral centers but the key is that it has to have AT LEAST 2. Hope this helps!

  • @MrYahya0101

    @MrYahya0101

    2 жыл бұрын

    ​@@ChadsPrep But if it has 3 then R+S wouldn't be in same ratio, so it would be optically active no? I also wanted to ask you about the cyclohexane you drew. You drew cyclohexane and said that it has plane of symmetry so it has superimposable mirror image. When you draw the mirror image do we consider the configuration of stereocenters to be reversed, eventhough they are not chiral centers? For non-superimposable mirror images, you can just say that the chiral centers were reversed, but superimposable mirror images have no chiral centers, how would you identify them? Thanks.

  • @ChadsPrep

    @ChadsPrep

    2 жыл бұрын

    You're exactly right Youssef, meso compounds are only possible with an even number of chiral centers. But they can exist with an odd number of stereocenters. Consider 1,2,4-cyclopentanetriol. Carbon atoms 1 and 2 will be chiral centers. Carbon atom 4 will be a stereocenter but not a chiral center (you can't assign it R/S). If carbons 1 and 2 have opposite configurations (one R and one S) it will be a meso compound. My bad but hope this helps!

  • @ChadsPrep

    @ChadsPrep

    2 жыл бұрын

    When you draw a mirror image the configurations of stereocenters won't necessarily be reversed. I haven't seen this come up before but if I consider the cyclohexane example and other such similar examples the stereocenters aren't reversed in the mirror image. I really want to say that will always be true, but the use of the word ALWAYS is dangerous. But I'm leaning that direction. Hope this helps!

  • @MrYahya0101

    @MrYahya0101

    2 жыл бұрын

    @@ChadsPrep Thanks Chad! So some molecules will have plane of symmetry and still not be meso compounds (cyclohexane), and some will not have a plane of symmetry (like the one at 18:30) and still be meso compounds? I mean doesn't that just mean we shouldn't use "plane of symmetry" to identify meso compounds?

  • @namchansawang8329
    @namchansawang83292 жыл бұрын

    Would you say your left hand and right butt cheek would be trans? 😅

  • @ChadsPrep

    @ChadsPrep

    2 жыл бұрын

    😆 😆 😆

  • @ablordestepheneyram9937
    @ablordestepheneyram9937Ай бұрын

    Talks too fast😢

  • @ChadsPrep

    @ChadsPrep

    Ай бұрын

    I get that a lot - you can slow down the playback speed under settings. Happy Studying!

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