Kinetic and thermodynamic enolates | Alpha Carbon Chemistry | Organic chemistry | Khan Academy

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  • เผยแพร่เมื่อ 23 ธ.ค. 2024

ความคิดเห็น • 13

  • @MisterTechnologic
    @MisterTechnologic 6 ปีที่แล้ว +2

    In my advanced organic synthesis class we are being taught that because of ring strain, even in 6 carbon rings, the allylic strain in a CYCLIC enolate introduced between the carbonyl and a substituent at the 2-position will make the bond between their two carbons in the cycle unfavorable.

  • @Morfeucomvoce
    @Morfeucomvoce 5 ปีที่แล้ว +3

    Great video. I'm still wondering tho if instead of a methyl group in the right side, it was a isoethyl group.

  • @PoppiD93
    @PoppiD93 8 ปีที่แล้ว +2

    Thanks! Very well explained!

  • @flow4458
    @flow4458 3 ปีที่แล้ว +1

    THANK YOU! SO GOOD!

  • @mahtabbasiri5961
    @mahtabbasiri5961 6 ปีที่แล้ว +1

    Thanks,it was perfect

  • @valeriagallippi9634
    @valeriagallippi9634 7 ปีที่แล้ว +2

    In the thermodynaic enolate, why didn't you take a proton from the other alpha carbon with three hyrogens? Is it because of the same reason explained in the kinetic enolate example?

    • @milanmilunovic3856
      @milanmilunovic3856 7 ปีที่แล้ว

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  • @curiouschemist7184
    @curiouschemist7184 5 ปีที่แล้ว

    Take tert- butoxide...which is again bulky....but major product is from more hindered site..to form Michael addition.....ref( clayden)...??? Why

  • @محمدالحديثي-ل8ت
    @محمدالحديثي-ل8ت 6 ปีที่แล้ว +1

    In thermodynamic enolate can we use base ( OH instead of (H ??

    • @peybak
      @peybak 5 ปีที่แล้ว +2

      I think you mean NaOH which is also an unhindered base. My guess would be yes.

  • @gregorykarimian3813
    @gregorykarimian3813 4 ปีที่แล้ว +1

    You did not explain why low temp favors the less substituted enolate versus the less. so i'll do it for you. you see LDA is a bulky base, so if it were to take the proton at the bulkier position, the activation energy would be very high for that reaction for obvious reason. too much steric clash. so it takes the other one instead. what can reduce activation energy? heat. so if you raise the temperature, you will reduce the activation energy for the reaction for the proton at the bulkier position . now this means they will both have the same activation energy since you added energy in the form of heat. now the question is which proton does it take? well since they both have the same activation energy and the more substituted enolate is more stable, it will obviously form the more substituted product at high temps. thus it will take the proton at the bulkier position, affording the more stable product since activation energy is not an issue anymore. this is why if we want to isolate the less substituted enolate for whatever reason, we have to use LDA at LOW temps and not high. remember thermodynamic stability is useless unless you're reaction is kinetically favored. that is why we use catalysts in the lab, and enzymes in our bodies. i hope this helped.

    • @embro5695
      @embro5695 3 ปีที่แล้ว

      I understand that more substituted enolate is more stable as Zaitsev’s rule claims, however how to bring it together with the fact that less substituted carbanion is more stable?

  • @guramritaujla6930
    @guramritaujla6930 7 ปีที่แล้ว +1